Type.GetField Method
Important
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Gets a specific field of the current Type.
GetField(String) |
Searches for the public field with the specified name. |
GetField(String, BindingFlags) |
Searches for the specified field, using the specified binding constraints. |
- Source:
- Type.cs
- Source:
- Type.cs
- Source:
- Type.cs
Searches for the public field with the specified name.
public:
System::Reflection::FieldInfo ^ GetField(System::String ^ name);
public:
virtual System::Reflection::FieldInfo ^ GetField(System::String ^ name);
public System.Reflection.FieldInfo? GetField (string name);
public System.Reflection.FieldInfo GetField (string name);
member this.GetField : string -> System.Reflection.FieldInfo
abstract member GetField : string -> System.Reflection.FieldInfo
override this.GetField : string -> System.Reflection.FieldInfo
Public Function GetField (name As String) As FieldInfo
Parameters
- name
- String
The string containing the name of the data field to get.
Returns
An object representing the public field with the specified name, if found; otherwise, null
.
Implements
Exceptions
name
is null
.
This Type object is a TypeBuilder whose CreateType() method has not yet been called.
Examples
The following example gets the Type
object for the specified class, obtains the FieldInfo object for the field, and displays the value of the field.
using namespace System;
using namespace System::Reflection;
using namespace System::Security;
public ref class MyFieldClassA
{
public:
String^ field;
MyFieldClassA()
{
field = "A Field";
}
property String^ Field
{
String^ get()
{
return field;
}
void set( String^ value )
{
if ( field != value )
{
field = value;
}
}
}
};
public ref class MyFieldClassB
{
public:
String^ field;
MyFieldClassB()
{
field = "B Field";
}
property String^ Field
{
String^ get()
{
return field;
}
void set( String^ value )
{
if ( field != value )
{
field = value;
}
}
}
};
int main()
{
try
{
MyFieldClassB^ myFieldObjectB = gcnew MyFieldClassB;
MyFieldClassA^ myFieldObjectA = gcnew MyFieldClassA;
Type^ myTypeA = Type::GetType( "MyFieldClassA" );
FieldInfo^ myFieldInfo = myTypeA->GetField( "field" );
Type^ myTypeB = Type::GetType( "MyFieldClassB" );
FieldInfo^ myFieldInfo1 = myTypeB->GetField( "field", static_cast<BindingFlags>(BindingFlags::Public | BindingFlags::Instance) );
Console::WriteLine( "The value of the field is : {0} ", myFieldInfo->GetValue( myFieldObjectA ) );
Console::WriteLine( "The value of the field is : {0} ", myFieldInfo1->GetValue( myFieldObjectB ) );
}
catch ( SecurityException^ e )
{
Console::WriteLine( "Exception Raised!" );
Console::WriteLine( "Message : {0}", e->Message );
}
catch ( ArgumentNullException^ e )
{
Console::WriteLine( "Exception Raised!" );
Console::WriteLine( "Message : {0}", e->Message );
}
catch ( Exception^ e )
{
Console::WriteLine( "Exception Raised!" );
Console::WriteLine( "Message : {0}", e->Message );
}
}
using System;
using System.Reflection;
public class MyFieldClassA
{
public string Field = "A Field";
}
public class MyFieldClassB
{
private string field = "B Field";
public string Field
{
get
{
return field;
}
set
{
if (field!=value)
{
field=value;
}
}
}
}
public class MyFieldInfoClass
{
public static void Main()
{
MyFieldClassB myFieldObjectB = new MyFieldClassB();
MyFieldClassA myFieldObjectA = new MyFieldClassA();
Type myTypeA = typeof(MyFieldClassA);
FieldInfo myFieldInfo = myTypeA.GetField("Field");
Type myTypeB = typeof(MyFieldClassB);
FieldInfo myFieldInfo1 = myTypeB.GetField("field",
BindingFlags.NonPublic | BindingFlags.Instance);
Console.WriteLine("The value of the public field is: '{0}'",
myFieldInfo.GetValue(myFieldObjectA));
Console.WriteLine("The value of the private field is: '{0}'",
myFieldInfo1.GetValue(myFieldObjectB));
}
}
open System.Reflection
type MyFieldClassA =
val public Field: string
new () = { Field = "A Field"}
type MyFieldClassB() =
let field = "B Field"
member _.Field
with get () = field
let myFieldObjectB = MyFieldClassB()
let myFieldObjectA = MyFieldClassA()
let myTypeA = typeof<MyFieldClassA>
let myFieldInfo = myTypeA.GetField "Field"
let myTypeB = typeof<MyFieldClassB>
let myFieldInfo1 = myTypeB.GetField("field", BindingFlags.NonPublic ||| BindingFlags.Instance)
printfn $"The value of the public field is: '{myFieldInfo.GetValue myFieldObjectA}'"
printfn $"The value of the private field is: '{myFieldInfo1.GetValue myFieldObjectB}'"
Imports System.Reflection
Public Class MyFieldClassA
Public Field As String = "A Field"
End Class
Public Class MyFieldClassB
Private myField As String = "B Field"
Public Property Field() As String
Get
Return myField
End Get
Set(ByVal Value As String)
If myField <> value Then
myField = value
End If
End Set
End Property
End Class
Public Class MyFieldInfoClass
Public Shared Sub Main()
Dim myFieldObjectB As New MyFieldClassB()
Dim myFieldObjectA As New MyFieldClassA()
Dim myTypeA As Type = GetType(MyFieldClassA)
Dim myFieldInfo As FieldInfo = myTypeA.GetField("Field")
Dim myTypeB As Type = GetType(MyFieldClassB)
Dim myFieldInfo1 As FieldInfo = myTypeB.GetField("myField", _
BindingFlags.NonPublic Or BindingFlags.Instance)
Console.WriteLine("The value of the public field is: '{0}'", _
myFieldInfo.GetValue(myFieldObjectA))
Console.WriteLine("The value of the private field is: '{0}'", _
myFieldInfo1.GetValue(myFieldObjectB))
End Sub
End Class
Remarks
The search for name
is case-sensitive. The search includes public static and public instance fields.
If the current Type represents a constructed generic type, this method returns the FieldInfo with the type parameters replaced by the appropriate type arguments.
If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the fields of the class constraint.
See also
Applies to
.NET 9 e outras versões
Produto | Versões |
---|---|
.NET | Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 2.0, 2.1 |
- Source:
- Type.cs
- Source:
- Type.cs
- Source:
- Type.cs
Searches for the specified field, using the specified binding constraints.
public:
abstract System::Reflection::FieldInfo ^ GetField(System::String ^ name, System::Reflection::BindingFlags bindingAttr);
public abstract System.Reflection.FieldInfo? GetField (string name, System.Reflection.BindingFlags bindingAttr);
public abstract System.Reflection.FieldInfo GetField (string name, System.Reflection.BindingFlags bindingAttr);
abstract member GetField : string * System.Reflection.BindingFlags -> System.Reflection.FieldInfo
Public MustOverride Function GetField (name As String, bindingAttr As BindingFlags) As FieldInfo
Parameters
- name
- String
The string containing the name of the data field to get.
- bindingAttr
- BindingFlags
A bitwise combination of the enumeration values that specify how the search is conducted.
-or-
Default to return null
.
Returns
An object representing the field that matches the specified requirements, if found; otherwise, null
.
Implements
Exceptions
name
is null
.
Examples
The following example gets the Type
object for the specified class, obtains the FieldInfo object for the field that matches the specified binding flags, and displays the value of the field.
using namespace System;
using namespace System::Reflection;
using namespace System::Security;
public ref class MyFieldClassA
{
public:
String^ field;
MyFieldClassA()
{
field = "A Field";
}
property String^ Field
{
String^ get()
{
return field;
}
void set( String^ value )
{
if ( field != value )
{
field = value;
}
}
}
};
public ref class MyFieldClassB
{
public:
String^ field;
MyFieldClassB()
{
field = "B Field";
}
property String^ Field
{
String^ get()
{
return field;
}
void set( String^ value )
{
if ( field != value )
{
field = value;
}
}
}
};
int main()
{
try
{
MyFieldClassB^ myFieldObjectB = gcnew MyFieldClassB;
MyFieldClassA^ myFieldObjectA = gcnew MyFieldClassA;
Type^ myTypeA = Type::GetType( "MyFieldClassA" );
FieldInfo^ myFieldInfo = myTypeA->GetField( "field" );
Type^ myTypeB = Type::GetType( "MyFieldClassB" );
FieldInfo^ myFieldInfo1 = myTypeB->GetField( "field", static_cast<BindingFlags>(BindingFlags::Public | BindingFlags::Instance) );
Console::WriteLine( "The value of the field is : {0} ", myFieldInfo->GetValue( myFieldObjectA ) );
Console::WriteLine( "The value of the field is : {0} ", myFieldInfo1->GetValue( myFieldObjectB ) );
}
catch ( SecurityException^ e )
{
Console::WriteLine( "Exception Raised!" );
Console::WriteLine( "Message : {0}", e->Message );
}
catch ( ArgumentNullException^ e )
{
Console::WriteLine( "Exception Raised!" );
Console::WriteLine( "Message : {0}", e->Message );
}
catch ( Exception^ e )
{
Console::WriteLine( "Exception Raised!" );
Console::WriteLine( "Message : {0}", e->Message );
}
}
using System;
using System.Reflection;
public class MyFieldClassA
{
public string Field = "A Field";
}
public class MyFieldClassB
{
private string field = "B Field";
public string Field
{
get
{
return field;
}
set
{
if (field!=value)
{
field=value;
}
}
}
}
public class MyFieldInfoClass
{
public static void Main()
{
MyFieldClassB myFieldObjectB = new MyFieldClassB();
MyFieldClassA myFieldObjectA = new MyFieldClassA();
Type myTypeA = typeof(MyFieldClassA);
FieldInfo myFieldInfo = myTypeA.GetField("Field");
Type myTypeB = typeof(MyFieldClassB);
FieldInfo myFieldInfo1 = myTypeB.GetField("field",
BindingFlags.NonPublic | BindingFlags.Instance);
Console.WriteLine("The value of the public field is: '{0}'",
myFieldInfo.GetValue(myFieldObjectA));
Console.WriteLine("The value of the private field is: '{0}'",
myFieldInfo1.GetValue(myFieldObjectB));
}
}
open System.Reflection
type MyFieldClassA =
val public Field: string
new () = { Field = "A Field"}
type MyFieldClassB() =
let field = "B Field"
member _.Field
with get () = field
let myFieldObjectB = MyFieldClassB()
let myFieldObjectA = MyFieldClassA()
let myTypeA = typeof<MyFieldClassA>
let myFieldInfo = myTypeA.GetField "Field"
let myTypeB = typeof<MyFieldClassB>
let myFieldInfo1 = myTypeB.GetField("field", BindingFlags.NonPublic ||| BindingFlags.Instance)
printfn $"The value of the public field is: '{myFieldInfo.GetValue myFieldObjectA}'"
printfn $"The value of the private field is: '{myFieldInfo1.GetValue myFieldObjectB}'"
Imports System.Reflection
Public Class MyFieldClassA
Public Field As String = "A Field"
End Class
Public Class MyFieldClassB
Private myField As String = "B Field"
Public Property Field() As String
Get
Return myField
End Get
Set(ByVal Value As String)
If myField <> value Then
myField = value
End If
End Set
End Property
End Class
Public Class MyFieldInfoClass
Public Shared Sub Main()
Dim myFieldObjectB As New MyFieldClassB()
Dim myFieldObjectA As New MyFieldClassA()
Dim myTypeA As Type = GetType(MyFieldClassA)
Dim myFieldInfo As FieldInfo = myTypeA.GetField("Field")
Dim myTypeB As Type = GetType(MyFieldClassB)
Dim myFieldInfo1 As FieldInfo = myTypeB.GetField("myField", _
BindingFlags.NonPublic Or BindingFlags.Instance)
Console.WriteLine("The value of the public field is: '{0}'", _
myFieldInfo.GetValue(myFieldObjectA))
Console.WriteLine("The value of the private field is: '{0}'", _
myFieldInfo1.GetValue(myFieldObjectB))
End Sub
End Class
Remarks
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.
The following BindingFlags filter flags can be used to define which fields to include in the search:
You must specify either
BindingFlags.Instance
orBindingFlags.Static
in order to get a return.Specify
BindingFlags.Public
to include public fields in the search.Specify
BindingFlags.NonPublic
to include non-public fields (that is, private, internal, and protected fields) in the search.Specify
BindingFlags.FlattenHierarchy
to includepublic
andprotected
static members up the hierarchy;private
static members in inherited classes are not included.
The following BindingFlags modifier flags can be used to change how the search works:
BindingFlags.IgnoreCase
to ignore the case ofname
.BindingFlags.DeclaredOnly
to search only the fields declared on the Type, not fields that were simply inherited.
See System.Reflection.BindingFlags for more information.
If the current Type represents a constructed generic type, this method returns the FieldInfo with the type parameters replaced by the appropriate type arguments.
If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the fields of the class constraint.
See also
Applies to
.NET 9 e outras versões
Produto | Versões |
---|---|
.NET | Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 2.0, 2.1 |
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