Type.GetType Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets a Type object that represents the specified type.
Overloads
GetType() |
Gets the current Type. |
GetType(String) |
Gets the Type with the specified name, performing a case-sensitive search. |
GetType(String, Boolean) |
Gets the Type with the specified name, performing a case-sensitive search and specifying whether to throw an exception if the type is not found. |
GetType(String, Boolean, Boolean) |
Gets the Type with the specified name, specifying whether to throw an exception if the type is not found and whether to perform a case-sensitive search. |
GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>) |
Gets the type with the specified name, optionally providing custom methods to resolve the assembly and the type. |
GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean) |
Gets the type with the specified name, specifying whether to throw an exception if the type is not found, and optionally providing custom methods to resolve the assembly and the type. |
GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean, Boolean) |
Gets the type with the specified name, specifying whether to perform a case-sensitive search and whether to throw an exception if the type is not found, and optionally providing custom methods to resolve the assembly and the type. |
GetType()
Gets the current Type.
public:
Type ^ GetType();
public:
virtual Type ^ GetType();
public Type GetType ();
override this.GetType : unit -> Type
Public Function GetType () As Type
Returns
The current Type.
Implements
Exceptions
A class initializer is invoked and throws an exception.
See also
Applies to
GetType(String)
Gets the Type with the specified name, performing a case-sensitive search.
public:
static Type ^ GetType(System::String ^ typeName);
public static Type GetType (string typeName);
public static Type? GetType (string typeName);
static member GetType : string -> Type
Public Shared Function GetType (typeName As String) As Type
Parameters
- typeName
- String
The assembly-qualified name of the type to get. See AssemblyQualifiedName. If the type is in the currently executing assembly or in mscorlib.dll/System.Private.CoreLib.dll, it is sufficient to supply the type name qualified by its namespace.
Returns
The type with the specified name, if found; otherwise, null
.
Exceptions
typeName
is null
.
A class initializer is invoked and throws an exception.
typeName
represents a generic type that has a pointer type, a ByRef
type, or Void as one of its type arguments.
-or-
typeName
represents a generic type that has an incorrect number of type arguments.
-or-
typeName
represents a generic type, and one of its type arguments does not satisfy the constraints for the corresponding type parameter.
typeName
represents an array of TypedReference.
The assembly or one of its dependencies was found, but could not be loaded.
Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, IOException, instead.
The assembly or one of its dependencies is not valid.
-or-
Version 2.0 or later of the common language runtime is currently loaded, and the assembly was compiled with a later version.
Examples
The following example retrieves the type of System.Int32
and uses that type object to display the FullName property of System.Int32
.
using namespace System;
int main()
{
try {
// Get the type of a specified class.
Type^ myType1 = Type::GetType( "System.Int32" );
Console::WriteLine( "The full name is {0}.\n", myType1->FullName );
}
catch ( TypeLoadException^ e ) {
Console::WriteLine("{0}: Unable to load type System.Int32",
e->GetType()->Name);
}
try {
// Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
Type^ myType2 = Type::GetType( "NoneSuch", true );
Console::WriteLine( "The full name is {0}.", myType2->FullName );
}
catch ( TypeLoadException^ e ) {
Console::WriteLine("{0}: Unable to load type NoneSuch",
e->GetType()->Name);
}
}
// The example displays the following output:
// The full name is System.Int32.
//
// TypeLoadException: Unable to load type NoneSuch
using System;
class Example
{
public static void Main()
{
try {
// Get the type of a specified class.
Type myType1 = Type.GetType("System.Int32");
Console.WriteLine("The full name is {0}.\n", myType1.FullName);
}
catch (TypeLoadException e)
{
Console.WriteLine("{0}: Unable to load type System.Int32", e.GetType().Name);
}
try {
// Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
Type myType2 = Type.GetType("NoneSuch", true);
Console.WriteLine("The full name is {0}.", myType2.FullName);
}
catch(TypeLoadException e) {
Console.WriteLine("{0}: Unable to load type NoneSuch", e.GetType().Name);
}
}
}
// The example displays the following output:
// The full name is System.Int32.
//
// TypeLoadException: Unable to load type NoneSuch
open System
try
// Get the type of a specified class.
let myType1 = Type.GetType "System.Int32"
printfn $"The full name is {myType1.FullName}.\n"
with :? TypeLoadException as e ->
printfn $"{e.GetType().Name}: Unable to load type System.Int32"
try
// Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
let myType2 = Type.GetType("NoneSuch", true)
printfn $"The full name is {myType2.FullName}."
with :? TypeLoadException as e ->
printfn $"{e.GetType().Name}: Unable to load type NoneSuch"
// The example displays the following output:
// The full name is System.Int32.
//
// TypeLoadException: Unable to load type NoneSuch
Class Example
Public Shared Sub Main()
Try
' Get the type of the specified class.
Dim myType1 As Type = Type.GetType("System.Int32")
Console.WriteLine("The full name is {0}.", myType1.FullName)
Catch e As TypeLoadException
Console.WriteLine("{0}: Unable to load type System.Int32",
e.GetType().Name)
End Try
Console.WriteLine()
Try
' Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
Dim myType2 As Type = Type.GetType("NoneSuch", True)
Console.WriteLine("The full name is {0}.", myType2.FullName)
Catch e As TypeLoadException
Console.WriteLine("{0}: Unable to load type NoneSuch", e.GetType().Name)
End Try
End Sub
End Class
' The example displays the following output:
' The full name is System.Int32.
'
' TypeLoadException: Unable to load type NoneSuch
Remarks
You can use the GetType method to obtain a Type object for a type in another assembly if you know its assembly-qualified name, which can be obtained from AssemblyQualifiedName. GetType causes loading of the assembly specified in typeName
. You can also load an assembly using the Assembly.Load method, and then use the Assembly.GetType or Assembly.GetTypes method to get Type objects. If a type is in an assembly known to your program at compile time, it is more efficient to use typeof
in C# or the GetType
operator in Visual Basic.
Note
If typeName
cannot be found, the call to the GetType(String) method returns null
. It does not throw an exception. To control whether an exception is thrown, call an overload of the GetType method that has a throwOnError
parameter.
GetType only works on assemblies loaded from disk. If you call GetType to look up a type defined in a dynamic assembly defined using the System.Reflection.Emit services, you might get inconsistent behavior. The behavior depends on whether the dynamic assembly is persistent, that is, created using the RunAndSave
or Save
access modes of the System.Reflection.Emit.AssemblyBuilderAccess enumeration. If the dynamic assembly is persistent and has been written to disk before GetType
is called, the loader finds the saved assembly on disk, loads that assembly, and retrieves the type from that assembly. If the assembly has not been saved to disk when GetType
is called, the method returns null
. GetType
does not understand transient dynamic assemblies; therefore, calling GetType
to retrieve a type in a transient dynamic assembly returns null
.
To use GetType
on a dynamic module, subscribe to the AppDomain.AssemblyResolve event and call GetType
before saving. Otherwise, you will get two copies of the assembly in memory.
The following table shows what members of a base class are returned by the Get
methods when reflecting on a type.
Member Type | Static | Non-Static |
---|---|---|
Constructor | No | No |
Field | No | Yes. A field is always hide-by-name-and-signature. |
Event | Not applicable | The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Method | No | Yes. A method (both virtual and non-virtual) can be hide-by-name or hide-by-name-and-signature. |
Nested Type | No | No |
Property | Not applicable | The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Hide-by-name-and-signature considers all of the parts of the signature, including custom modifiers, return types, parameter types, sentinels, and unmanaged calling conventions. This is a binary comparison.
For reflection, properties and events are hide-by-name-and-signature. If you have a property with both a get and a set accessor in the base class, but the derived class has only a get accessor, the derived class property hides the base class property, and you will not be able to access the setter on the base class.
Custom attributes are not part of the common type system.
Arrays or COM types are not searched for unless they have already been loaded into the table of available classes.
typeName
can be the type name qualified by its namespace or an assembly-qualified name that includes an assembly name specification. See AssemblyQualifiedName.
If typeName
includes the namespace but not the assembly name, this method searches only the calling object's assembly and mscorlib.dll/System.Private.CoreLib.dll, in that order. If typeName is fully qualified with the partial or complete assembly name, this method searches in the specified assembly. If the assembly has a strong name, a complete assembly name is required.
The AssemblyQualifiedName property returns a fully qualified type name including nested types, the assembly name, and generic type arguments. All compilers that support the common language runtime will emit the simple name of a nested class, and reflection constructs a mangled name when queried, in accordance with the following conventions.
Note
In the .NET Framework version 2.0, processor architecture is added to assembly identity, and can be specified as part of assembly name strings. For example, "ProcessorArchitecture=msil". However, it is not included in the string returned by the AssemblyQualifiedName property, for compatibility reasons. You can also load types by creating an AssemblyName object and passing it to an appropriate overload of the Load method. You can then use the Assembly.GetType method to load types from the assembly. See also AssemblyName.ProcessorArchitecture.
Delimiter | Meaning |
---|---|
Backslash (\) | Escape character. |
Backtick (`) | Precedes one or more digits representing the number of type parameters, located at the end of the name of a generic type. |
Brackets ([]) | Enclose a generic type argument list, for a constructed generic type; within a type argument list, enclose an assembly-qualified type. |
Comma (,) | Precedes the Assembly name. |
Period (.) | Denotes namespace identifiers. |
Plus sign (+) | Precedes a nested class. |
For example, the fully qualified name for a class might look like this:
TopNamespace.SubNameSpace.ContainingClass+NestedClass,MyAssembly
If the namespace were TopNamespace.Sub+Namespace, then the string would have to precede the plus sign (+) with an escape character (\) to prevent it from being interpreted as a nesting separator. Reflection emits this string as follows:
TopNamespace.Sub\+Namespace.ContainingClass+NestedClass,MyAssembly
A "++" becomes "\+\+", and a "\" becomes "\\".
This qualified name can be persisted and later used to load the Type. To search for and load a Type, use GetType either with the type name only or with the assembly qualified type name. GetType with the type name only will look for the Type in the caller's assembly and then in the System assembly. GetType with the assembly qualified type name will look for the Type in any assembly.
Type names may include trailing characters that denote additional information about the type, such as whether the type is a reference type, a pointer type or an array type. To retrieve the type name without these trailing characters, use t.GetElementType().ToString()
, where t
is the type.
Spaces are relevant in all type name components except the assembly name. In the assembly name, spaces before the ',' separator are relevant, but spaces after the ',' separator are ignored.
The name of a generic type ends with a backtick (`) followed by digits representing the number of generic type arguments. The purpose of this name mangling is to allow compilers to support generic types with the same name but with different numbers of type parameters, occurring in the same scope. For example, reflection returns the mangled names Tuple`1
and Tuple`2
from the generic methods Tuple(Of T)
and Tuple(Of T0, T1)
in Visual Basic, or Tuple<T>
and Tuple<T0, T1>
in Visual C#.
For generic types, the type argument list is enclosed in brackets, and the type arguments are separated by commas. For example, a generic Dictionary<TKey,TValue> has two type parameters. A Dictionary<TKey,TValue> of MyType
with keys of type String might be represented as follows:
System.Collections.Generic.Dictionary`2[System.String,MyType]
To specify an assembly-qualified type within a type argument list, enclose the assembly-qualified type within brackets. Otherwise, the commas that separate the parts of the assembly-qualified name are interpreted as delimiting additional type arguments. For example, a Dictionary<TKey,TValue> of MyType
fromMyAssembly.dll, with keys of type String, might be specified as follows:
Type.GetType("System.Collections.Generic.Dictionary`2[System.String,[MyType,MyAssembly]]")
Note
An assembly-qualified type can be enclosed in brackets only when it appears within a type parameter list. The rules for searching assemblies for qualified and unqualified types in type parameter lists are the same as the rules for qualified and unqualified nongeneric types.
Nullable types are a special case of generic types. For example, a nullable Int32 is represented by the string "System.Nullable`1[System.Int32]".
Note
In C#, C++, and Visual Basic you can also get nullable types using type operators. For example, the nullable Boolean type is returned by typeof(Nullable<bool>)
in C#, by Nullable<Boolean>::typeid
in C++, and by GetType(Nullable(Of Boolean))
in Visual Basic.
The following table shows the syntax you use with GetType
for various types.
To Get | Use |
---|---|
A nullable Int32 | Type.GetType("System.Nullable`1[System.Int32]") |
An unmanaged pointer to MyType |
Type.GetType("MyType*") |
An unmanaged pointer to a pointer to MyType |
Type.GetType("MyType**") |
A managed pointer or reference to MyType |
Type.GetType("MyType&") . Note that unlike pointers, references are limited to one level. |
A parent class and a nested class | Type.GetType("MyParentClass+MyNestedClass") |
A one-dimensional array with a lower bound of 0 | Type.GetType("MyType[]") |
A one-dimensional array with an unknown lower bound | Type.GetType("MyType[*]") |
An n-dimensional array | A comma (,) inside the brackets a total of n-1 times. For example, System.Object[,,] represents a three-dimensional Object array. |
An array of one-dimensional arrays | Type.GetType("MyType[][]") |
A rectangular two-dimensional array with unknown lower bounds | Type.GetType("MyType[,]") |
A generic type with one type argument | Type.GetType("MyGenericType`1[MyType]") |
A generic type with two type arguments | Type.GetType("MyGenericType`2[MyType,AnotherType]") |
A generic type with two assembly-qualified type arguments | Type.GetType("MyGenericType`2[[MyType,MyAssembly],[AnotherType,AnotherAssembly]]") |
An assembly-qualified generic type with an assembly-qualified type argument | Type.GetType("MyGenericType`1[[MyType,MyAssembly]],MyGenericTypeAssembly") |
A generic type whose type argument is a generic type with two type arguments | Type.GetType("MyGenericType`1[AnotherGenericType`2[MyType,AnotherType]]") |
See also
- String
- TypeLoadException
- AssemblyQualifiedName
- GetAssembly(Type)
- GetType(String)
- AssemblyName
- Specifying Fully Qualified Type Names
Applies to
GetType(String, Boolean)
Gets the Type with the specified name, performing a case-sensitive search and specifying whether to throw an exception if the type is not found.
public:
static Type ^ GetType(System::String ^ typeName, bool throwOnError);
public static Type GetType (string typeName, bool throwOnError);
public static Type? GetType (string typeName, bool throwOnError);
static member GetType : string * bool -> Type
Public Shared Function GetType (typeName As String, throwOnError As Boolean) As Type
Parameters
- typeName
- String
The assembly-qualified name of the type to get. See AssemblyQualifiedName. If the type is in the currently executing assembly or in mscorlib.dll/System.Private.CoreLib.dll, it is sufficient to supply the type name qualified by its namespace.
- throwOnError
- Boolean
true
to throw an exception if the type cannot be found; false
to return null
. Specifying false
also suppresses some other exception conditions, but not all of them. See the Exceptions section.
Returns
The type with the specified name. If the type is not found, the throwOnError
parameter specifies whether null
is returned or an exception is thrown. In some cases, an exception is thrown regardless of the value of throwOnError
. See the Exceptions section.
Exceptions
typeName
is null
.
A class initializer is invoked and throws an exception.
throwOnError
is true
and the type is not found.
-or-
throwOnError
is true
and typeName
contains invalid characters, such as an embedded tab.
-or-
throwOnError
is true
and typeName
is an empty string.
-or-
throwOnError
is true
and typeName
represents an array type with an invalid size.
-or-
typeName
represents an array of TypedReference.
throwOnError
is true
and typeName
contains invalid syntax. For example, "MyType[,*,]".
-or-
typeName
represents a generic type that has a pointer type, a ByRef
type, or Void as one of its type arguments.
-or-
typeName
represents a generic type that has an incorrect number of type arguments.
-or-
typeName
represents a generic type, and one of its type arguments does not satisfy the constraints for the corresponding type parameter.
throwOnError
is true
and the assembly or one of its dependencies was not found.
The assembly or one of its dependencies was found, but could not be loaded.
Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, IOException, instead.
The assembly or one of its dependencies is not valid.
-or-
Version 2.0 or later of the common language runtime is currently loaded, and the assembly was compiled with a later version.
Examples
The following example retrieves the type of System.Int32
and uses that type object to display the FullName property of System.Int32
. If a type object refers to an assembly that does not exist, this example throws an exception.
using namespace System;
int main()
{
try {
// Get the type of a specified class.
Type^ myType1 = Type::GetType( "System.Int32" );
Console::WriteLine( "The full name is {0}.\n", myType1->FullName );
}
catch ( TypeLoadException^ e ) {
Console::WriteLine("{0}: Unable to load type System.Int32",
e->GetType()->Name);
}
try {
// Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
Type^ myType2 = Type::GetType( "NoneSuch", true );
Console::WriteLine( "The full name is {0}.", myType2->FullName );
}
catch ( TypeLoadException^ e ) {
Console::WriteLine("{0}: Unable to load type NoneSuch",
e->GetType()->Name);
}
}
// The example displays the following output:
// The full name is System.Int32.
//
// TypeLoadException: Unable to load type NoneSuch
using System;
class Example
{
public static void Main()
{
try {
// Get the type of a specified class.
Type myType1 = Type.GetType("System.Int32");
Console.WriteLine("The full name is {0}.\n", myType1.FullName);
}
catch (TypeLoadException e)
{
Console.WriteLine("{0}: Unable to load type System.Int32", e.GetType().Name);
}
try {
// Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
Type myType2 = Type.GetType("NoneSuch", true);
Console.WriteLine("The full name is {0}.", myType2.FullName);
}
catch(TypeLoadException e) {
Console.WriteLine("{0}: Unable to load type NoneSuch", e.GetType().Name);
}
}
}
// The example displays the following output:
// The full name is System.Int32.
//
// TypeLoadException: Unable to load type NoneSuch
open System
try
// Get the type of a specified class.
let myType1 = Type.GetType "System.Int32"
printfn $"The full name is {myType1.FullName}.\n"
with :? TypeLoadException as e ->
printfn $"{e.GetType().Name}: Unable to load type System.Int32"
try
// Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
let myType2 = Type.GetType("NoneSuch", true)
printfn $"The full name is {myType2.FullName}."
with :? TypeLoadException as e ->
printfn $"{e.GetType().Name}: Unable to load type NoneSuch"
// The example displays the following output:
// The full name is System.Int32.
//
// TypeLoadException: Unable to load type NoneSuch
Class Example
Public Shared Sub Main()
Try
' Get the type of the specified class.
Dim myType1 As Type = Type.GetType("System.Int32")
Console.WriteLine("The full name is {0}.", myType1.FullName)
Catch e As TypeLoadException
Console.WriteLine("{0}: Unable to load type System.Int32",
e.GetType().Name)
End Try
Console.WriteLine()
Try
' Since NoneSuch does not exist in this assembly, GetType throws a TypeLoadException.
Dim myType2 As Type = Type.GetType("NoneSuch", True)
Console.WriteLine("The full name is {0}.", myType2.FullName)
Catch e As TypeLoadException
Console.WriteLine("{0}: Unable to load type NoneSuch", e.GetType().Name)
End Try
End Sub
End Class
' The example displays the following output:
' The full name is System.Int32.
'
' TypeLoadException: Unable to load type NoneSuch
Remarks
You can use the GetType method to obtain a Type object for a type in another assembly if you know its assembly-qualified name, which can be obtained from AssemblyQualifiedName. GetType causes loading of the assembly specified in typeName
. You can also load an assembly using the Assembly.Load method, and then use the Assembly.GetType or Assembly.GetTypes method to get Type objects. If a type is in an assembly known to your program at compile time, it is more efficient to use typeof
in C# or the GetType
operator in Visual Basic.
GetType
only works on assemblies loaded from disk. If you call GetType
to look up a type defined in a dynamic assembly defined using the System.Reflection.Emit services, you might get inconsistent behavior. The behavior depends on whether the dynamic assembly is persistent, that is, created using the RunAndSave
or Save
access modes of the System.Reflection.Emit.AssemblyBuilderAccess enumeration. If the dynamic assembly is persistent and has been written to disk before GetType
is called, the loader finds the saved assembly on disk, loads that assembly, and retrieves the type from that assembly. If the assembly has not been saved to disk when GetType
is called, the method returns null
. GetType
does not understand transient dynamic assemblies; therefore, calling GetType
to retrieve a type in a transient dynamic assembly returns null
.
To use GetType
on a dynamic module, subscribe to the AppDomain.AssemblyResolve event and call GetType
before saving. Otherwise, you will get two copies of the assembly in memory.
The throwOnError
parameter specifies what happens when the type is not found, and also suppresses certain other exception conditions, as described in the Exceptions section. Some exceptions are thrown regardless of the value of throwOnError
. For example, if the type is found but cannot be loaded, a TypeLoadException is thrown even if throwOnError
is false
.
The following table shows what members of a base class are returned by the Get
methods when reflecting on a type.
Member Type | Static | Non-Static |
---|---|---|
Constructor | No | No |
Field | No | Yes. A field is always hide-by-name-and-signature. |
Event | Not applicable | The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Method | No | Yes. A method (both virtual and non-virtual) can be hide-by-name or hide-by-name-and-signature. |
Nested Type | No | No |
Property | Not applicable | The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Hide-by-name-and-signature considers all of the parts of the signature, including custom modifiers, return types, parameter types, sentinels, and unmanaged calling conventions. This is a binary comparison.
For reflection, properties and events are hide-by-name-and-signature. If you have a property with both a get and a set accessor in the base class, but the derived class has only a get accessor, the derived class property hides the base class property, and you will not be able to access the setter on the base class.
Custom attributes are not part of the common type system.
Arrays or COM types are not searched for unless they have already been loaded into the table of available classes.
typeName
can be the type name qualified by its namespace or an assembly-qualified name that includes an assembly name specification. See AssemblyQualifiedName.
If typeName
includes the namespace but not the assembly name, this method searches only the calling object's assembly and mscorlib.dll/System.Private.CoreLib.dll, in that order. If typeName is fully qualified with the partial or complete assembly name, this method searches in the specified assembly. If the assembly has a strong name, a complete assembly name is required.
The AssemblyQualifiedName property returns a fully qualified type name including nested types, the assembly name, and generic arguments. All compilers that support the common language runtime will emit the simple name of a nested class, and reflection constructs a mangled name when queried, in accordance with the following conventions.
Note
In the .NET Framework version 2.0, processor architecture is added to assembly identity, and can be specified as part of assembly name strings. For example, "ProcessorArchitecture=msil". However, it is not included in the string returned by the AssemblyQualifiedName property, for compatibility reasons. You can also load types by creating an AssemblyName object and passing it to an appropriate overload of the Load method. You can then use the Assembly.GetType method to load types from the assembly. See also AssemblyName.ProcessorArchitecture.
Delimiter | Meaning |
---|---|
Backslash (\) | Escape character. |
Backtick (`) | Precedes one or more digits representing the number of type parameters, located at the end of the name of a generic type. |
Brackets ([]) | Enclose a generic type argument list, for a constructed generic type; within a type argument list, enclose an assembly-qualified type. |
Comma (,) | Precedes the Assembly name. |
Period (.) | Denotes namespace identifiers. |
Plus sign (+) | Precedes a nested class. |
For example, the fully qualified name for a class might look like this:
TopNamespace.SubNameSpace.ContainingClass+NestedClass,MyAssembly
If the namespace were TopNamespace.Sub+Namespace, then the string would have to precede the plus sign (+) with an escape character (\) to prevent it from being interpreted as a nesting separator. Reflection emits this string as follows:
TopNamespace.Sub\+Namespace.ContainingClass+NestedClass,MyAssembly
A "++" becomes "\+\+", and a "\" becomes "\\".
This qualified name can be persisted and later used to load the Type. To search for and load a Type, use GetType either with the type name only or with the assembly qualified type name. GetType with the type name only will look for the Type in the caller's assembly and then in the System assembly. GetType with the assembly qualified type name will look for the Type in any assembly.
Type names may include trailing characters that denote additional information about the type, such as whether the type is a reference type, a pointer type or an array type. To retrieve the type name without these trailing characters, use t.GetElementType().ToString()
, where t
is the type.
Spaces are relevant in all type name components except the assembly name. In the assembly name, spaces before the ',' separator are relevant, but spaces after the ',' separator are ignored.
The name of a generic type ends with a backtick (`) followed by digits representing the number of generic type arguments. The purpose of this name mangling is to allow compilers to support generic types with the same name but with different numbers of type parameters, occurring in the same scope. For example, reflection returns the mangled names Tuple`1
and Tuple`2
from the generic methods Tuple(Of T)
and Tuple(Of T0, T1)
in Visual Basic, or Tuple<T>
and Tuple<T0, T1>
in Visual C#.
For generic types, the type argument list is enclosed in brackets, and the type arguments are separated by commas. For example, a generic Dictionary<TKey,TValue> has two type parameters. A Dictionary<TKey,TValue> of MyType
with keys of type String might be represented as follows:
System.Collections.Generic.Dictionary`2[System.String,MyType]
To specify an assembly-qualified type within a type argument list, enclose the assembly-qualified type within brackets. Otherwise, the commas that separate the parts of the assembly-qualified name are interpreted as delimiting additional type arguments. For example, a Dictionary<TKey,TValue> of MyType
from MyAssembly.dll, with keys of type String, might be specified as follows:
Type.GetType("System.Collections.Generic.Dictionary`2[System.String,[MyType,MyAssembly]]")
Note
An assembly-qualified type can be enclosed in brackets only when it appears within a type parameter list. The rules for searching assemblies for qualified and unqualified types in type parameter lists are the same as the rules for qualified and unqualified nongeneric types.
Nullable types are a special case of generic types. For example, a nullable Int32 is represented by the string "System.Nullable`1[System.Int32]".
Note
In C#, C++, and Visual Basic you can also get nullable types using type operators. For example, the nullable Boolean type is returned by typeof(Nullable<bool>)
in C#, by Nullable<Boolean>::typeid
in C++, and by GetType(Nullable(Of Boolean))
in Visual Basic.
The following table shows the syntax you use with GetType
for various types.
To Get | Use |
---|---|
A nullable Int32 | Type.GetType("System.Nullable`1[System.Int32]") |
An unmanaged pointer to MyType |
Type.GetType("MyType*") |
An unmanaged pointer to a pointer to MyType |
Type.GetType("MyType**") |
A managed pointer or reference to MyType |
Type.GetType("MyType&") . Note that unlike pointers, references are limited to one level. |
A parent class and a nested class | Type.GetType("MyParentClass+MyNestedClass") |
A one-dimensional array with a lower bound of 0 | Type.GetType("MyArray[]") |
A one-dimensional array with an unknown lower bound | Type.GetType("MyArray[*]") |
An n-dimensional array | A comma (,) inside the brackets a total of n-1 times. For example, System.Object[,,] represents a three-dimensional Object array. |
A two-dimensional array's array | Type.GetType("MyArray[][]") |
A rectangular two-dimensional array with unknown lower bounds | Type.GetType("MyArray[,]") |
A generic type with one type argument | Type.GetType("MyGenericType`1[MyType]") |
A generic type with two type arguments | Type.GetType("MyGenericType`2[MyType,AnotherType]") |
A generic type with two assembly-qualified type arguments | Type.GetType("MyGenericType`2[[MyType,MyAssembly],[AnotherType,AnotherAssembly]]") |
An assembly-qualified generic type with an assembly-qualified type argument | Type.GetType("MyGenericType`1[[MyType,MyAssembly]],MyGenericTypeAssembly") |
A generic type whose type argument is a generic type with two type arguments | Type.GetType("MyGenericType`1[AnotherGenericType`2[MyType,AnotherType]]") |
See also
- String
- TypeLoadException
- AssemblyQualifiedName
- GetAssembly(Type)
- GetType(String)
- AssemblyName
- Specifying Fully Qualified Type Names
Applies to
GetType(String, Boolean, Boolean)
Gets the Type with the specified name, specifying whether to throw an exception if the type is not found and whether to perform a case-sensitive search.
public:
static Type ^ GetType(System::String ^ typeName, bool throwOnError, bool ignoreCase);
public static Type GetType (string typeName, bool throwOnError, bool ignoreCase);
public static Type? GetType (string typeName, bool throwOnError, bool ignoreCase);
static member GetType : string * bool * bool -> Type
Public Shared Function GetType (typeName As String, throwOnError As Boolean, ignoreCase As Boolean) As Type
Parameters
- typeName
- String
The assembly-qualified name of the type to get. See AssemblyQualifiedName. If the type is in the currently executing assembly or in mscorlib.dll/System.Private.CoreLib.dll, it is sufficient to supply the type name qualified by its namespace.
- throwOnError
- Boolean
true
to throw an exception if the type cannot be found; false
to return null
. Specifying false
also suppresses some other exception conditions, but not all of them. See the Exceptions section.
- ignoreCase
- Boolean
true
to perform a case-insensitive search for typeName
, false
to perform a case-sensitive search for typeName
.
Returns
The type with the specified name. If the type is not found, the throwOnError
parameter specifies whether null
is returned or an exception is thrown. In some cases, an exception is thrown regardless of the value of throwOnError
. See the Exceptions section.
Exceptions
typeName
is null
.
A class initializer is invoked and throws an exception.
throwOnError
is true
and the type is not found.
-or-
throwOnError
is true
and typeName
contains invalid characters, such as an embedded tab.
-or-
throwOnError
is true
and typeName
is an empty string.
-or-
throwOnError
is true
and typeName
represents an array type with an invalid size.
-or-
typeName
represents an array of TypedReference.
throwOnError
is true
and typeName
contains invalid syntax. For example, "MyType[,*,]".
-or-
typeName
represents a generic type that has a pointer type, a ByRef
type, or Void as one of its type arguments.
-or-
typeName
represents a generic type that has an incorrect number of type arguments.
-or-
typeName
represents a generic type, and one of its type arguments does not satisfy the constraints for the corresponding type parameter.
throwOnError
is true
and the assembly or one of its dependencies was not found.
The assembly or one of its dependencies was found, but could not be loaded.
The assembly or one of its dependencies is not valid.
-or-
Version 2.0 or later of the common language runtime is currently loaded, and the assembly was compiled with a later version.
Remarks
You can use the GetType method to obtain a Type object for a type in another assembly if you know its assembly-qualified name, which can be obtained from AssemblyQualifiedName. GetType causes loading of the assembly specified in typeName
. You can also load an assembly using the Assembly.Load method, and then use the Assembly.GetType or Assembly.GetTypes method to get Type objects. If a type is in an assembly known to your program at compile time, it is more efficient to use typeof
in C# or the GetType
operator in Visual Basic.
GetType
only works on assemblies loaded from disk. If you call GetType
to look up a type defined in a dynamic assembly defined using the System.Reflection.Emit services, you might get inconsistent behavior. The behavior depends on whether the dynamic assembly is persistent, that is, created using the RunAndSave
or Save
access modes of the System.Reflection.Emit.AssemblyBuilderAccess enumeration. If the dynamic assembly is persistent and has been written to disk before GetType
is called, the loader finds the saved assembly on disk, loads that assembly, and retrieves the type from that assembly. If the assembly has not been saved to disk when GetType
is called, the method returns null
. GetType
does not understand transient dynamic assemblies; therefore, calling GetType
to retrieve a type in a transient dynamic assembly returns null
.
To use GetType
on a dynamic module, subscribe to the AppDomain.AssemblyResolve event and call GetType
before saving. Otherwise, you will get two copies of the assembly in memory.
The throwOnError
parameter specifies what happens when the type is not found, and also suppresses certain other exception conditions, as described in the Exceptions section. Some exceptions are thrown regardless of the value of throwOnError
. For example, if the type is found but cannot be loaded, a TypeLoadException is thrown even if throwOnError
is false
.
The following table shows what members of a base class are returned by the Get
methods when reflecting on a type.
Member Type | Static | Non-Static |
---|---|---|
Constructor | No | No |
Field | No | Yes. A field is always hide-by-name-and-signature. |
Event | Not applicable | The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Method | No | Yes. A method (both virtual and non-virtual) can be hide-by-name or hide-by-name-and-signature. |
Nested Type | No | No |
Property | Not applicable | The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Hide-by-name-and-signature considers all of the parts of the signature, including custom modifiers, return types, parameter types, sentinels, and unmanaged calling conventions. This is a binary comparison.
For reflection, properties and events are hide-by-name-and-signature. If you have a property with both a get and a set accessor in the base class, but the derived class has only a get accessor, the derived class property hides the base class property, and you will not be able to access the setter on the base class.
Custom attributes are not part of the common type system.
Arrays or COM types are not searched for unless they have already been loaded into the table of available classes.
typeName
can be the type name qualified by its namespace or an assembly-qualified name that includes an assembly name specification. See AssemblyQualifiedName.
If typeName
includes the namespace but not the assembly name, this method searches only the calling object's assembly and mscorlib.dll/System.Private.CoreLib.dll, in that order. If typeName is fully qualified with the partial or complete assembly name, this method searches in the specified assembly. If the assembly has a strong name, a complete assembly name is required.
The AssemblyQualifiedName property returns a fully qualified type name including nested types, the assembly name, and type arguments. All compilers that support the common language runtime will emit the simple name of a nested class, and reflection constructs a mangled name when queried, in accordance with the following conventions.
Note
In the .NET Framework version 2.0, processor architecture is added to assembly identity, and can be specified as part of assembly name strings. For example, "ProcessorArchitecture=msil". However, it is not included in the string returned by the AssemblyQualifiedName property, for compatibility reasons. You can also load types by creating an AssemblyName object and passing it to an appropriate overload of the Load method. You can then use the Assembly.GetType method to load types from the assembly. See also AssemblyName.ProcessorArchitecture.
Delimiter | Meaning |
---|---|
Backslash (\) | Escape character. |
Backtick (`) | Precedes one or more digits representing the number of type parameters, located at the end of the name of a generic type. |
Brackets ([]) | Enclose a generic type argument list, for a constructed generic type; within a type argument list, enclose an assembly-qualified type. |
Comma (,) | Precedes the Assembly name. |
Period (.) | Denotes namespace identifiers. |
Plus sign (+) | Precedes a nested class. |
For example, the fully qualified name for a class might look like this:
TopNamespace.SubNameSpace.ContainingClass+NestedClass,MyAssembly
If the namespace were TopNamespace.Sub+Namespace, then the string would have to precede the plus sign (+) with an escape character (\) to prevent it from being interpreted as a nesting separator. Reflection emits this string as follows:
TopNamespace.Sub\+Namespace.ContainingClass+NestedClass,MyAssembly
A "++" becomes "\+\+", and a "\" becomes "\\".
This qualified name can be persisted and later used to load the Type. To search for and load a Type, use GetType either with the type name only or with the assembly qualified type name. GetType with the type name only will look for the Type in the caller's assembly and then in the System assembly. GetType with the assembly qualified type name will look for the Type in any assembly.
Type names may include trailing characters that denote additional information about the type, such as whether the type is a reference type, a pointer type or an array type. To retrieve the type name without these trailing characters, use t.GetElementType().ToString()
, where t
is the type.
Spaces are relevant in all type name components except the assembly name. In the assembly name, spaces before the ',' separator are relevant, but spaces after the ',' separator are ignored.
The name of a generic type ends with a backtick (`) followed by digits representing the number of generic type arguments. The purpose of this name mangling is to allow compilers to support generic types with the same name but with different numbers of type parameters, occurring in the same scope. For example, reflection returns the mangled names Tuple`1
and Tuple`2
from the generic methods Tuple(Of T)
and Tuple(Of T0, T1)
in Visual Basic, or Tuple<T>
and Tuple<T0, T1>
in Visual C#.
For generic types, the type argument list is enclosed in brackets, and the type arguments are separated by commas. For example, a generic Dictionary<TKey,TValue> has two type parameters. A Dictionary<TKey,TValue> of MyType
with keys of type String might be represented as follows:
System.Collections.Generic.Dictionary`2[System.String,MyType]
To specify an assembly-qualified type within a type argument list, enclose the assembly-qualified type within brackets. Otherwise, the commas that separate the parts of the assembly-qualified name are interpreted as delimiting additional type arguments. For example, a Dictionary<TKey,TValue> of MyType
from MyAssembly.dll, with keys of type String, might be specified as follows:
Type.GetType("System.Collections.Generic.Dictionary`2[System.String,[MyType,MyAssembly]]")
Note
An assembly-qualified type can be enclosed in brackets only when it appears within a type parameter list. The rules for searching assemblies for qualified and unqualified types in type parameter lists are the same as the rules for qualified and unqualified nongeneric types.
Nullable types are a special case of generic types. For example, a nullable Int32 is represented by the string "System.Nullable`1[System.Int32]".
Note
In C#, C++, and Visual Basic you can also get nullable types using type operators. For example, the nullable Boolean type is returned by typeof(Nullable<bool>)
in C#, by Nullable<Boolean>::typeid
in C++, and by GetType(Nullable(Of Boolean))
in Visual Basic.
The following table shows the syntax you use with GetType
for various types.
To Get | Use |
---|---|
A nullable Int32 | Type.GetType("System.Nullable`1[System.Int32]") |
An unmanaged pointer to MyType |
Type.GetType("MyType*") |
An unmanaged pointer to a pointer to MyType |
Type.GetType("MyType**") |
A managed pointer or reference to MyType |
Type.GetType("MyType&") . Note that unlike pointers, references are limited to one level. |
A parent class and a nested class | Type.GetType("MyParentClass+MyNestedClass") |
A one-dimensional array with a lower bound of 0 | Type.GetType("MyArray[]") |
A one-dimensional array with an unknown lower bound | Type.GetType("MyArray[*]") |
An n-dimensional array | A comma (,) inside the brackets a total of n-1 times. For example, System.Object[,,] represents a three-dimensional Object array. |
A two-dimensional array's array | Type.GetType("MyArray[][]") |
A rectangular two-dimensional array with unknown lower bounds | Type.GetType("MyArray[,]") |
A generic type with one type argument | Type.GetType("MyGenericType`1[MyType]") |
A generic type with two type arguments | Type.GetType("MyGenericType`2[MyType,AnotherType]") |
A generic type with two assembly-qualified type arguments | Type.GetType("MyGenericType`2[[MyType,MyAssembly],[AnotherType,AnotherAssembly]]") |
An assembly-qualified generic type with an assembly-qualified type argument | Type.GetType("MyGenericType`1[[MyType,MyAssembly]],MyGenericTypeAssembly") |
A generic type whose type argument is a generic type with two type arguments | Type.GetType("MyGenericType`1[AnotherGenericType`2[MyType,AnotherType]]") |
See also
- String
- TypeLoadException
- AssemblyQualifiedName
- GetAssembly(Type)
- GetType(String)
- AssemblyName
- Specifying Fully Qualified Type Names
Applies to
GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>)
Gets the type with the specified name, optionally providing custom methods to resolve the assembly and the type.
public:
static Type ^ GetType(System::String ^ typeName, Func<System::Reflection::AssemblyName ^, System::Reflection::Assembly ^> ^ assemblyResolver, Func<System::Reflection::Assembly ^, System::String ^, bool, Type ^> ^ typeResolver);
public static Type? GetType (string typeName, Func<System.Reflection.AssemblyName,System.Reflection.Assembly?>? assemblyResolver, Func<System.Reflection.Assembly?,string,bool,Type?>? typeResolver);
public static Type GetType (string typeName, Func<System.Reflection.AssemblyName,System.Reflection.Assembly> assemblyResolver, Func<System.Reflection.Assembly,string,bool,Type> typeResolver);
static member GetType : string * Func<System.Reflection.AssemblyName, System.Reflection.Assembly> * Func<System.Reflection.Assembly, string, bool, Type> -> Type
Public Shared Function GetType (typeName As String, assemblyResolver As Func(Of AssemblyName, Assembly), typeResolver As Func(Of Assembly, String, Boolean, Type)) As Type
Parameters
- typeName
- String
The name of the type to get. If the typeResolver
parameter is provided, the type name can be any string that typeResolver
is capable of resolving. If the assemblyResolver
parameter is provided or if standard type resolution is used, typeName
must be an assembly-qualified name (see AssemblyQualifiedName), unless the type is in the currently executing assembly or in mscorlib.dll/System.Private.CoreLib.dll, in which case it is sufficient to supply the type name qualified by its namespace.
- assemblyResolver
- Func<AssemblyName,Assembly>
A method that locates and returns the assembly that is specified in typeName
. The assembly name is passed to assemblyResolver
as an AssemblyName object. If typeName
does not contain the name of an assembly, assemblyResolver
is not called. If assemblyResolver
is not supplied, standard assembly resolution is performed.
Caution Do not pass methods from unknown or untrusted callers. Doing so could result in elevation of privilege for malicious code. Use only methods that you provide or that you are familiar with.
A method that locates and returns the type that is specified by typeName
from the assembly that is returned by assemblyResolver
or by standard assembly resolution. If no assembly is provided, the typeResolver
method can provide one. The method also takes a parameter that specifies whether to perform a case-insensitive search; false
is passed to that parameter.
Caution Do not pass methods from unknown or untrusted callers.
Returns
The type with the specified name, or null
if the type is not found.
Exceptions
typeName
is null
.
A class initializer is invoked and throws an exception.
An error occurs when typeName
is parsed into a type name and an assembly name (for example, when the simple type name includes an unescaped special character).
-or-
typeName
represents a generic type that has a pointer type, a ByRef
type, or Void as one of its type arguments.
-or-
typeName
represents a generic type that has an incorrect number of type arguments.
-or-
typeName
represents a generic type, and one of its type arguments does not satisfy the constraints for the corresponding type parameter.
typeName
represents an array of TypedReference.
The assembly or one of its dependencies was found, but could not be loaded.
-or-
typeName
contains an invalid assembly name.
-or-
typeName
is a valid assembly name without a type name.
The assembly or one of its dependencies is not valid.
-or-
The assembly was compiled with a later version of the common language runtime than the version that is currently loaded.
Remarks
Usage scenarios for this method and details about the assemblyResolver
and typeResolver
parameters can be found in the GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean, Boolean) method overload.
Note
If typeName
cannot be found, the call to the GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>) method returns null
. It does not throw an exception. To control whether an exception is thrown, call an overload of the GetType method that has a throwOnError
parameter.
Calling this method overload is the same as calling the GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean, Boolean) method overload and specifying false
for the throwOnError
and ignoreCase
parameters.
Applies to
GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean)
Gets the type with the specified name, specifying whether to throw an exception if the type is not found, and optionally providing custom methods to resolve the assembly and the type.
public:
static Type ^ GetType(System::String ^ typeName, Func<System::Reflection::AssemblyName ^, System::Reflection::Assembly ^> ^ assemblyResolver, Func<System::Reflection::Assembly ^, System::String ^, bool, Type ^> ^ typeResolver, bool throwOnError);
public static Type? GetType (string typeName, Func<System.Reflection.AssemblyName,System.Reflection.Assembly?>? assemblyResolver, Func<System.Reflection.Assembly?,string,bool,Type?>? typeResolver, bool throwOnError);
public static Type GetType (string typeName, Func<System.Reflection.AssemblyName,System.Reflection.Assembly> assemblyResolver, Func<System.Reflection.Assembly,string,bool,Type> typeResolver, bool throwOnError);
static member GetType : string * Func<System.Reflection.AssemblyName, System.Reflection.Assembly> * Func<System.Reflection.Assembly, string, bool, Type> * bool -> Type
Public Shared Function GetType (typeName As String, assemblyResolver As Func(Of AssemblyName, Assembly), typeResolver As Func(Of Assembly, String, Boolean, Type), throwOnError As Boolean) As Type
Parameters
- typeName
- String
The name of the type to get. If the typeResolver
parameter is provided, the type name can be any string that typeResolver
is capable of resolving. If the assemblyResolver
parameter is provided or if standard type resolution is used, typeName
must be an assembly-qualified name (see AssemblyQualifiedName), unless the type is in the currently executing assembly or in mscorlib.dll/System.Private.CoreLib.dll, in which case it is sufficient to supply the type name qualified by its namespace.
- assemblyResolver
- Func<AssemblyName,Assembly>
A method that locates and returns the assembly that is specified in typeName
. The assembly name is passed to assemblyResolver
as an AssemblyName object. If typeName
does not contain the name of an assembly, assemblyResolver
is not called. If assemblyResolver
is not supplied, standard assembly resolution is performed.
Caution Do not pass methods from unknown or untrusted callers. Doing so could result in elevation of privilege for malicious code. Use only methods that you provide or that you are familiar with.
A method that locates and returns the type that is specified by typeName
from the assembly that is returned by assemblyResolver
or by standard assembly resolution. If no assembly is provided, the method can provide one. The method also takes a parameter that specifies whether to perform a case-insensitive search; false
is passed to that parameter.
Caution Do not pass methods from unknown or untrusted callers.
- throwOnError
- Boolean
true
to throw an exception if the type cannot be found; false
to return null
. Specifying false
also suppresses some other exception conditions, but not all of them. See the Exceptions section.
Returns
The type with the specified name. If the type is not found, the throwOnError
parameter specifies whether null
is returned or an exception is thrown. In some cases, an exception is thrown regardless of the value of throwOnError
. See the Exceptions section.
Exceptions
typeName
is null
.
A class initializer is invoked and throws an exception.
throwOnError
is true
and the type is not found.
-or-
throwOnError
is true
and typeName
contains invalid characters, such as an embedded tab.
-or-
throwOnError
is true
and typeName
is an empty string.
-or-
throwOnError
is true
and typeName
represents an array type with an invalid size.
-or-
typeName
represents an array of TypedReference.
An error occurs when typeName
is parsed into a type name and an assembly name (for example, when the simple type name includes an unescaped special character).
-or-
throwOnError
is true
and typeName
contains invalid syntax (for example, "MyType[,*,]").
-or-
typeName
represents a generic type that has a pointer type, a ByRef
type, or Void as one of its type arguments.
-or-
typeName
represents a generic type that has an incorrect number of type arguments.
-or-
typeName
represents a generic type, and one of its type arguments does not satisfy the constraints for the corresponding type parameter.
throwOnError
is true
and the assembly or one of its dependencies was not found.
-or-
typeName
contains an invalid assembly name.
-or-
typeName
is a valid assembly name without a type name.
The assembly or one of its dependencies was found, but could not be loaded.
The assembly or one of its dependencies is not valid.
-or-
The assembly was compiled with a later version of the common language runtime than the version that is currently loaded.
Remarks
Usage scenarios for this method and details about the assemblyResolver
and typeResolver
parameters can be found in the GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean, Boolean) method overload.
Calling this method overload is the same as calling the GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean, Boolean) method overload and specifying false
for the ignoreCase
parameter.
Applies to
GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean, Boolean)
Gets the type with the specified name, specifying whether to perform a case-sensitive search and whether to throw an exception if the type is not found, and optionally providing custom methods to resolve the assembly and the type.
public:
static Type ^ GetType(System::String ^ typeName, Func<System::Reflection::AssemblyName ^, System::Reflection::Assembly ^> ^ assemblyResolver, Func<System::Reflection::Assembly ^, System::String ^, bool, Type ^> ^ typeResolver, bool throwOnError, bool ignoreCase);
public static Type? GetType (string typeName, Func<System.Reflection.AssemblyName,System.Reflection.Assembly?>? assemblyResolver, Func<System.Reflection.Assembly?,string,bool,Type?>? typeResolver, bool throwOnError, bool ignoreCase);
public static Type GetType (string typeName, Func<System.Reflection.AssemblyName,System.Reflection.Assembly> assemblyResolver, Func<System.Reflection.Assembly,string,bool,Type> typeResolver, bool throwOnError, bool ignoreCase);
static member GetType : string * Func<System.Reflection.AssemblyName, System.Reflection.Assembly> * Func<System.Reflection.Assembly, string, bool, Type> * bool * bool -> Type
Public Shared Function GetType (typeName As String, assemblyResolver As Func(Of AssemblyName, Assembly), typeResolver As Func(Of Assembly, String, Boolean, Type), throwOnError As Boolean, ignoreCase As Boolean) As Type
Parameters
- typeName
- String
The name of the type to get. If the typeResolver
parameter is provided, the type name can be any string that typeResolver
is capable of resolving. If the assemblyResolver
parameter is provided or if standard type resolution is used, typeName
must be an assembly-qualified name (see AssemblyQualifiedName), unless the type is in the currently executing assembly or in mscorlib.dll/System.Private.CoreLib.dll, in which case it is sufficient to supply the type name qualified by its namespace.
- assemblyResolver
- Func<AssemblyName,Assembly>
A method that locates and returns the assembly that is specified in typeName
. The assembly name is passed to assemblyResolver
as an AssemblyName object. If typeName
does not contain the name of an assembly, assemblyResolver
is not called. If assemblyResolver
is not supplied, standard assembly resolution is performed.
Caution Do not pass methods from unknown or untrusted callers. Doing so could result in elevation of privilege for malicious code. Use only methods that you provide or that you are familiar with.
A method that locates and returns the type that is specified by typeName
from the assembly that is returned by assemblyResolver
or by standard assembly resolution. If no assembly is provided, the method can provide one. The method also takes a parameter that specifies whether to perform a case-insensitive search; the value of ignoreCase
is passed to that parameter.
Caution Do not pass methods from unknown or untrusted callers.
- throwOnError
- Boolean
true
to throw an exception if the type cannot be found; false
to return null
. Specifying false
also suppresses some other exception conditions, but not all of them. See the Exceptions section.
- ignoreCase
- Boolean
true
to perform a case-insensitive search for typeName
, false
to perform a case-sensitive search for typeName
.
Returns
The type with the specified name. If the type is not found, the throwOnError
parameter specifies whether null
is returned or an exception is thrown. In some cases, an exception is thrown regardless of the value of throwOnError
. See the Exceptions section.
Exceptions
typeName
is null
.
A class initializer is invoked and throws an exception.
throwOnError
is true
and the type is not found.
-or-
throwOnError
is true
and typeName
contains invalid characters, such as an embedded tab.
-or-
throwOnError
is true
and typeName
is an empty string.
-or-
throwOnError
is true
and typeName
represents an array type with an invalid size.
-or-
typeName
represents an array of TypedReference.
An error occurs when typeName
is parsed into a type name and an assembly name (for example, when the simple type name includes an unescaped special character).
-or-
throwOnError
is true
and typeName
contains invalid syntax (for example, "MyType[,*,]").
-or-
typeName
represents a generic type that has a pointer type, a ByRef
type, or Void as one of its type arguments.
-or-
typeName
represents a generic type that has an incorrect number of type arguments.
-or-
typeName
represents a generic type, and one of its type arguments does not satisfy the constraints for the corresponding type parameter.
throwOnError
is true
and the assembly or one of its dependencies was not found.
The assembly or one of its dependencies was found, but could not be loaded.
-or-
typeName
contains an invalid assembly name.
-or-
typeName
is a valid assembly name without a type name.
The assembly or one of its dependencies is not valid.
-or-
The assembly was compiled with a later version of the common language runtime than the version that is currently loaded.
Remarks
Use this method overload and its associated overloads (GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>) and GetType(String, Func<AssemblyName,Assembly>, Func<Assembly,String,Boolean,Type>, Boolean)) to replace the default implementation of the GetType method with more flexible implementations. By providing your own methods that resolve type names and the names of the assemblies that contain them, you can do the following:
Control which version of an assembly a type is loaded from.
Provide another place to look for a type name that does not include an assembly name.
Load assemblies using partial assembly names.
Return subclasses of System.Type that are not created by the common language runtime (CLR).
For example, in version-tolerant serialization this method enables you to search for a "best fit" assembly by using a partial name. Other overloads of the GetType method require an assembly-qualified type name, which includes the version number.
Alternate implementations of the type system may need to return subclasses of System.Type that are not created by the CLR; all types that are returned by other overloads of the GetType method are runtime types.
Usage Notes
This method overload and its associated overloads parse typeName
into the name of a type and the name of an assembly, and then resolve the names. Resolution of the assembly name occurs before resolution of the type name, because a type name must be resolved in the context of an assembly.
Note
If you are unfamiliar with the concept of assembly-qualified type names, see the AssemblyQualifiedName property.
If typeName
is not an assembly-qualified name, assembly resolution is skipped. Unqualified type names can be resolved in the context of mscorlib.dll/System.Private.CoreLib.dll or the currently executing assembly, or you can optionally provide an assembly in the typeResolver
parameter. The effects of including or omitting the assembly name for different kinds of name resolution are displayed as a table in the Mixed Name Resolution section.
General usage notes:
Do not pass methods to
assemblyResolver
ortypeResolver
if they come from unknown or untrusted callers. Use only methods that you provide or that you are familiar with.Caution
Using methods from unknown or untrusted callers could result in elevation of privilege for malicious code.
If you omit the
assemblyResolver
and/ortypeResolver
parameters, the value of thethrowOnError
parameter is passed to the methods that perform the default resolution.If
throwOnError
istrue
, this method throws a TypeLoadException whentypeResolver
returnsnull
, and a FileNotFoundException whenassemblyResolver
returnsnull
.This method does not catch exceptions thrown by
assemblyResolver
andtypeResolver
. You are responsible for any exceptions that are thrown by the resolver methods.
Resolving Assemblies
The assemblyResolver
method receives an AssemblyName object, which is produced by parsing the string assembly name that is included in typeName
. If typeName
does not contain an assembly name, assemblyResolver
is not called and null
is passed to typeResolver
.
If assemblyResolver
is not supplied, standard assembly probing is used to locate the assembly. If assemblyResolver
is provided, the GetType method does not do standard probing; in that case you must ensure that your assemblyResolver
can handle all the assemblies you pass to it.
The assemblyResolver
method should return null
if the assembly cannot be resolved. If assemblyResolver
returns null
, typeResolver
is not called and no further processing occurs; additionally, if throwOnError
is true
, a FileNotFoundException is thrown.
If the AssemblyName that is passed to assemblyResolver
is a partial name, one or more of its parts are null
. For example, if it has no version, the Version property is null
. If the Version property, the CultureInfo property, and the GetPublicKeyToken method all return null
, then only the simple name of the assembly was supplied. The assemblyResolver
method can use or ignore all parts of the assembly name.
The effects of different assembly resolution options are displayed as a table in the Mixed Name Resolution section, for simple and assembly-qualified type names.
Resolving Types
If typeName
does not specify an assembly name, typeResolver
is always called. If typeName
specifies an assembly name, typeResolver
is called only when the assembly name is successfully resolved. If assemblyResolver
or standard assembly probing returns null
, typeResolver
is not called.
The typeResolver
method receives three arguments:
The assembly to search or
null
iftypeName
does not contain an assembly name.The simple name of the type. In the case of a nested type, this is the outermost containing type. In the case of a generic type, this is the simple name of the generic type.
A Boolean value that is
true
if the case of type names is to be ignored.
The implementation determines the way these arguments are used. The typeResolver
method should return null
if it cannot resolve the type. If typeResolver
returns null
and throwOnError
is true
, this overload of GetType throws a TypeLoadException.
The effects of different type resolution options are displayed as a table in the Mixed Name Resolution section, for simple and assembly-qualified type names.
Resolving Nested Types
If typeName
is a nested type, only the name of the outermost containing type is passed to typeResolver
. When typeResolver
returns this type, the GetNestedType method is called recursively until the innermost nested type has been resolved.
Resolving Generic Types
The GetType is called recursively to resolve generic types: First to resolve the generic type itself, and then to resolve its type arguments. If a type argument is generic, GetType is called recursively to resolve its type arguments, and so on.
The combination of assemblyResolver
and typeResolver
that you provide must be capable of resolving all levels of this recursion. For example, suppose you supply an assemblyResolver
that controls the loading of MyAssembly
. Suppose you want to resolve the generic type Dictionary<string, MyType>
(Dictionary(Of String, MyType)
in Visual Basic). You might pass the following generic type name:
"System.Collections.Generic.Dictionary`2[System.String,[MyNamespace.MyType, MyAssembly]]"
Notice that MyType
is the only assembly-qualified type argument. The names of the Dictionary<TKey,TValue> and String classes are not assembly-qualified. Your typeResolver
must be able handle either an assembly or null
, because it will receive null
for Dictionary<TKey,TValue> and String. It can handle that case by calling an overload of the GetType method that takes a string, because both of the unqualified type names are in mscorlib.dll/System.Private.CoreLib.dll:
Type t = Type.GetType(test,
(aName) => aName.Name == "MyAssembly" ?
Assembly.LoadFrom(@".\MyPath\v5.0\MyAssembly.dll") : null,
(assem, name, ignore) => assem == null ?
Type.GetType(name, false, ignore) :
assem.GetType(name, false, ignore)
);
let t =
Type.GetType(test,
(fun aName ->
if aName.Name = "MyAssembly" then
Assembly.LoadFrom @".\MyPath\v5.0\MyAssembly.dll"
else null),
fun assem name ignr ->
if assem = null then
Type.GetType(name, false, ignr)
else
assem.GetType(name, false, ignr))
The assemblyResolver
method is not called for the dictionary type and the string type, because those type names are not assembly-qualified.
Now suppose that instead of System.String
, the first generic argument type is YourType
, from YourAssembly
:
"System.Collections.Generic.Dictionary`2[[YourNamespace.YourType, YourAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null], [MyNamespace.MyType, MyAssembly]]"
Because this assembly is neither mscorlib.dll/System.Private.CoreLib.dll nor the currently executing assembly, you cannot resolve YourType
without an assembly-qualified name. Because your assemblyResolve
will be called recursively, it must be able to handle this case. Instead of returning null
for assemblies other than MyAssembly
, it now performs an assembly load using the supplied AssemblyName object.
Type t2 = Type.GetType(test,
(aName) => aName.Name == "MyAssembly" ?
Assembly.LoadFrom(@".\MyPath\v5.0\MyAssembly.dll") :
Assembly.Load(aName),
(assem, name, ignore) => assem == null ?
Type.GetType(name, false, ignore) :
assem.GetType(name, false, ignore), true
);
let t2 =
Type.GetType(test,
(fun aName ->
if aName.Name = "MyAssembly" then
Assembly.LoadFrom @".\MyPath\v5.0\MyAssembly.dll"
else Assembly.Load aName),
(fun assem name ignr ->
if assem = null then
Type.GetType(name, false, ignr)
else
assem.GetType(name, false, ignr)), true)
Back to Usage Notes.
Resolving Type Names with Special Characters
Certain characters have special meanings in assembly-qualified names. If a simple type name contains these characters, the characters cause parsing errors when the simple name is part of an assembly-qualified name. To avoid the parsing errors, you must escape the special characters with a backslash before you can pass the assembly-qualified name to the GetType method. For example, if a type is named Strange]Type
, the escape character must be added ahead of the square bracket as follows: Strange\]Type
.
Note
Names with such special characters cannot be created in Visual Basic or C#, but can be created by using Microsoft intermediate language (MSIL) or by emitting dynamic assemblies.
The following table shows the special characters for type names.
Character | Meaning |
---|---|
, (comma) |
Delimiter for assembly-qualified names. |
[] (square brackets) |
As a suffix pair, indicates an array type; as a delimiter pair, encloses generic argument lists and assembly-qualified names. |
& (ampersand) |
As a suffix, indicates that a type is a reference type. |
* (asterisk) |
As a suffix, indicates that a type is a pointer type. |
+ (plus) |
Delimiter for nested types. |
\ (backslash) |
Escape character. |
Properties such as AssemblyQualifiedName return correctly escaped strings. You must pass correctly escaped strings to the GetType method. In turn, the GetType method passes correctly escaped names to typeResolver
and to the default type resolution methods. If you need to compare a name to an unescaped name in typeResolver
, you must remove the escape characters.
Back to Usage Notes.
Mixed Name Resolution
The following table summarizes the interactions between assemblyResolver
, typeResolver
, and default name resolution, for all combinations of type name and assembly name in typeName
:
Contents of type name | Assembly resolver method | Type resolver method | Result |
---|---|---|---|
type, assembly | null | null | Equivalent to calling the Type.GetType(String, Boolean, Boolean) method overload. |
type, assembly | provided | null | assemblyResolver returns the assembly or returns null if it cannot resolve the assembly. If the assembly is resolved, the Assembly.GetType(String, Boolean, Boolean) method overload is used to load the type from the assembly; otherwise, there is no attempt to resolve the type. |
type, assembly | null | provided | Equivalent to converting the assembly name to an AssemblyName object and calling the Assembly.Load(AssemblyName) method overload to get the assembly. If the assembly is resolved, it is passed to typeResolver ; otherwise, typeResolver is not called and there is no further attempt to resolve the type. |
type, assembly | provided | provided | assemblyResolver returns the assembly or returns null if it cannot resolve the assembly. If the assembly is resolved, it is passed to typeResolver ; otherwise, typeResolver is not called and there is no further attempt to resolve the type. |
type | null, provided | null | Equivalent to calling the Type.GetType(String, Boolean, Boolean) method overload. Because the assembly name is not provided, only mscorlib.dll/System.Private.CoreLib.dll and the currently executing assembly are searched. If assemblyResolver is provided, it is ignored. |
type | null, provided | provided | typeResolver is called, and null is passed for the assembly. typeResolver can provide a type from any assembly, including assemblies it loads for the purpose. If assemblyResolver is provided, it is ignored. |
assembly | null, provided | null, provided | A FileLoadException is thrown, because the assembly name is parsed as if it were an assembly-qualified type name. This results in an invalid assembly name. |
Back to: Usage Notes, Resolving Assemblies, Resolving Types.