FieldBuilder Class
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.
Defines and represents a field. This class cannot be inherited.
public ref class FieldBuilder sealed : System::Reflection::FieldInfo
public ref class FieldBuilder abstract : System::Reflection::FieldInfo
public ref class FieldBuilder sealed : System::Reflection::FieldInfo, System::Runtime::InteropServices::_FieldBuilder
public sealed class FieldBuilder : System.Reflection.FieldInfo
public abstract class FieldBuilder : System.Reflection.FieldInfo
[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)]
public sealed class FieldBuilder : System.Reflection.FieldInfo, System.Runtime.InteropServices._FieldBuilder
[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)]
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class FieldBuilder : System.Reflection.FieldInfo, System.Runtime.InteropServices._FieldBuilder
type FieldBuilder = class
inherit FieldInfo
[<System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)>]
type FieldBuilder = class
inherit FieldInfo
interface _FieldBuilder
[<System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type FieldBuilder = class
inherit FieldInfo
interface _FieldBuilder
Public NotInheritable Class FieldBuilder
Inherits FieldInfo
Public MustInherit Class FieldBuilder
Inherits FieldInfo
Public NotInheritable Class FieldBuilder
Inherits FieldInfo
Implements _FieldBuilder
- Inheritance
- Attributes
- Implements
Examples
The following example illustrates the use of the FieldBuilder
class.
using System;
using System.Reflection;
using System.Reflection.Emit;
public class FieldBuilder_Sample
{
private static Type? CreateType()
{
// Create an assembly.
AssemblyName assemName = new AssemblyName();
assemName.Name = "DynamicAssembly";
AssemblyBuilder assemBuilder =
AssemblyBuilder.DefineDynamicAssembly(assemName, AssemblyBuilderAccess.Run);
// Create a dynamic module in Dynamic Assembly.
ModuleBuilder modBuilder = assemBuilder.DefineDynamicModule("DynamicModule");
// Define a public class named "DynamicClass" in the assembly.
TypeBuilder typBuilder = modBuilder.DefineType("DynamicClass", TypeAttributes.Public);
// Define a private String field named "DynamicField" in the type.
FieldBuilder fldBuilder = typBuilder.DefineField("DynamicField",
typeof(string), FieldAttributes.Private | FieldAttributes.Static);
// Create the constructor.
Type[] constructorArgs = { typeof(String) };
ConstructorBuilder constructor = typBuilder.DefineConstructor(
MethodAttributes.Public, CallingConventions.Standard, constructorArgs);
ILGenerator constructorIL = constructor.GetILGenerator();
constructorIL.Emit(OpCodes.Ldarg_0);
ConstructorInfo? superConstructor = typeof(Object).GetConstructor(new Type[0]);
constructorIL.Emit(OpCodes.Call, superConstructor!);
constructorIL.Emit(OpCodes.Ldarg_0);
constructorIL.Emit(OpCodes.Ldarg_1);
constructorIL.Emit(OpCodes.Stfld, fldBuilder);
constructorIL.Emit(OpCodes.Ret);
// Create the DynamicMethod method.
MethodBuilder methBuilder = typBuilder.DefineMethod("DynamicMethod",
MethodAttributes.Public, typeof(String), null);
ILGenerator methodIL = methBuilder.GetILGenerator();
methodIL.Emit(OpCodes.Ldarg_0);
methodIL.Emit(OpCodes.Ldfld, fldBuilder);
methodIL.Emit(OpCodes.Ret);
Console.WriteLine($"Name : {fldBuilder.Name}");
Console.WriteLine($"DeclaringType : {fldBuilder.DeclaringType}");
Console.WriteLine($"Type : {fldBuilder.FieldType}");
return typBuilder.CreateType();
}
public static void Main()
{
Type? dynType = CreateType();
try
{
if (dynType is not null)
{
// Create an instance of the "HelloWorld" class.
Object? helloWorld = Activator.CreateInstance(dynType, new Object[] { "HelloWorld" });
// Invoke the "DynamicMethod" method of the "DynamicClass" class.
Object? obj = dynType.InvokeMember("DynamicMethod",
BindingFlags.InvokeMethod, null, helloWorld, null);
Console.WriteLine($"DynamicClass.DynamicMethod returned: \"{obj}\"");
}
}
catch (MethodAccessException e)
{
Console.WriteLine($"{e.GetType().Name}: {e.Message}");
}
}
}
Imports System.Reflection
Imports System.Reflection.Emit
Public Module FieldBuilder_Sample
Private Function CreateType() As Type
' Create an assembly.
Dim assemName As New AssemblyName()
assemName.Name = "DynamicAssembly"
Dim assemBuilder As AssemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemName,
AssemblyBuilderAccess.Run)
' Create a dynamic module in Dynamic Assembly.
Dim modBuilder As ModuleBuilder = assemBuilder.DefineDynamicModule("DynamicModule")
' Define a public class named "DynamicClass" in the assembly.
Dim typBuilder As TypeBuilder = modBuilder.DefineType("DynamicClass",
TypeAttributes.Public)
' Define a private String field named "DynamicField" in the type.
Dim fldBuilder As FieldBuilder = typBuilder.DefineField("DynamicField",
GetType(String), FieldAttributes.Private Or FieldAttributes.Static)
' Create the constructor.
Dim constructorArgs As Type() = {GetType(String)}
Dim constructor As ConstructorBuilder =
typBuilder.DefineConstructor(MethodAttributes.Public,
CallingConventions.Standard, constructorArgs)
Dim constructorIL As ILGenerator = constructor.GetILGenerator()
constructorIL.Emit(OpCodes.Ldarg_0)
Dim superConstructor As ConstructorInfo = GetType(Object).GetConstructor(New Type() {})
constructorIL.Emit(OpCodes.Call, superConstructor)
constructorIL.Emit(OpCodes.Ldarg_0)
constructorIL.Emit(OpCodes.Ldarg_1)
constructorIL.Emit(OpCodes.Stfld, fldBuilder)
constructorIL.Emit(OpCodes.Ret)
' Create the DynamicMethod method.
Dim methBuilder As MethodBuilder = typBuilder.DefineMethod("DynamicMethod",
MethodAttributes.Public, GetType(String), Nothing)
Dim methodIL As ILGenerator = methBuilder.GetILGenerator()
methodIL.Emit(OpCodes.Ldarg_0)
methodIL.Emit(OpCodes.Ldfld, fldBuilder)
methodIL.Emit(OpCodes.Ret)
Console.WriteLine($"Name : {fldBuilder.Name}")
Console.WriteLine($"DeclaringType : {fldBuilder.DeclaringType}")
Console.WriteLine($"Type : {fldBuilder.FieldType}")
Return typBuilder.CreateType()
End Function
Public Sub Main()
Dim dynType As Type = CreateType()
Try
' Create an instance of the "HelloWorld" class.
Dim helloWorld As Object = Activator.CreateInstance(dynType, New Object() {"HelloWorld"})
' Invoke the "DynamicMethod" method of the "DynamicClass" class.
Dim obj As Object = dynType.InvokeMember("DynamicMethod",
BindingFlags.InvokeMethod, Nothing, helloWorld, Nothing)
Console.WriteLine($"DynamicClass.DynamicMethod returned: ""{obj}""")
Catch e As MethodAccessException
Console.WriteLine($"{e.GetType().Name}: {e.Message}")
End Try
End Sub
End Module
Remarks
Get an instance of FieldBuilder
by calling DefineField, DefineInitializedData, or DefineUninitializedData.
Note
The SetValue method is currently not supported. As a workaround, retrieve the FieldInfo by reflecting on the finished type and call SetValue to set the value of the field.
Constructors
FieldBuilder() |
Initializes a new instance of the FieldBuilder class. |
Properties
Attributes |
Indicates the attributes of this field. This property is read-only. |
CustomAttributes |
Gets a collection that contains this member's custom attributes. (Inherited from MemberInfo) |
DeclaringType |
Indicates a reference to the Type object for the type that declares this field. This property is read-only. |
FieldHandle |
Indicates the internal metadata handle for this field. This property is read-only. |
FieldHandle |
Gets a |
FieldType |
Indicates the Type object that represents the type of this field. This property is read-only. |
IsAssembly |
Gets a value indicating whether the potential visibility of this field is described by Assembly; that is, the field is visible at most to other types in the same assembly, and is not visible to derived types outside the assembly. (Inherited from FieldInfo) |
IsCollectible |
Gets a value that indicates whether this MemberInfo object is part of an assembly held in a collectible AssemblyLoadContext. (Inherited from MemberInfo) |
IsFamily |
Gets a value indicating whether the visibility of this field is described by Family; that is, the field is visible only within its class and derived classes. (Inherited from FieldInfo) |
IsFamilyAndAssembly |
Gets a value indicating whether the visibility of this field is described by FamANDAssem; that is, the field can be accessed from derived classes, but only if they are in the same assembly. (Inherited from FieldInfo) |
IsFamilyOrAssembly |
Gets a value indicating whether the potential visibility of this field is described by FamORAssem; that is, the field can be accessed by derived classes wherever they are, and by classes in the same assembly. (Inherited from FieldInfo) |
IsInitOnly |
Gets a value indicating whether the field can only be set in the body of the constructor. (Inherited from FieldInfo) |
IsLiteral |
Gets a value indicating whether the value is written at compile time and cannot be changed. (Inherited from FieldInfo) |
IsNotSerialized |
Obsolete.
Gets a value indicating whether this field has the |
IsPinvokeImpl |
Gets a value indicating whether the corresponding |
IsPrivate |
Gets a value indicating whether the field is private. (Inherited from FieldInfo) |
IsPublic |
Gets a value indicating whether the field is public. (Inherited from FieldInfo) |
IsSecurityCritical |
Gets a value that indicates whether the current field is security-critical or security-safe-critical at the current trust level. (Inherited from FieldInfo) |
IsSecuritySafeCritical |
Gets a value that indicates whether the current field is security-safe-critical at the current trust level. (Inherited from FieldInfo) |
IsSecurityTransparent |
Gets a value that indicates whether the current field is transparent at the current trust level. (Inherited from FieldInfo) |
IsSpecialName |
Gets a value indicating whether the corresponding |
IsStatic |
Gets a value indicating whether the field is static. (Inherited from FieldInfo) |
MemberType |
Gets a MemberTypes value indicating that this member is a field. (Inherited from FieldInfo) |
MetadataToken |
Gets a token that identifies the current dynamic module in metadata. |
MetadataToken |
Gets a value that identifies a metadata element. (Inherited from MemberInfo) |
Module |
Gets the module in which the type that contains this field is being defined. |
Module |
Gets the module in which the type that declares the member represented by the current MemberInfo is defined. (Inherited from MemberInfo) |
Name |
Indicates the name of this field. This property is read-only. |
ReflectedType |
Indicates the reference to the Type object from which this object was obtained. This property is read-only. |
ReflectedType |
Gets the class object that was used to obtain this instance of |
Methods
Equals(Object) |
Returns a value that indicates whether this instance is equal to a specified object. (Inherited from FieldInfo) |
GetCustomAttributes(Boolean) |
Returns all the custom attributes defined for this field. |
GetCustomAttributes(Boolean) |
When overridden in a derived class, returns an array of all custom attributes applied to this member. (Inherited from MemberInfo) |
GetCustomAttributes(Type, Boolean) |
Returns all the custom attributes defined for this field identified by the given type. |
GetCustomAttributes(Type, Boolean) |
When overridden in a derived class, returns an array of custom attributes applied to this member and identified by Type. (Inherited from MemberInfo) |
GetCustomAttributesData() |
Returns a list of CustomAttributeData objects representing data about the attributes that have been applied to the target member. (Inherited from MemberInfo) |
GetHashCode() |
Returns the hash code for this instance. (Inherited from FieldInfo) |
GetModifiedFieldType() |
Gets the modified type of this field object. (Inherited from FieldInfo) |
GetOptionalCustomModifiers() |
Gets an array of types that identify the optional custom modifiers of the field. (Inherited from FieldInfo) |
GetRawConstantValue() |
Returns a literal value associated with the field by a compiler. (Inherited from FieldInfo) |
GetRequiredCustomModifiers() |
Gets an array of types that identify the required custom modifiers of the property. (Inherited from FieldInfo) |
GetToken() |
Returns the token representing this field. |
GetType() |
Discovers the attributes of a class field and provides access to field metadata. (Inherited from FieldInfo) |
GetValue(Object) |
Retrieves the value of the field supported by the given object. |
GetValueDirect(TypedReference) |
Returns the value of a field supported by a given object. (Inherited from FieldInfo) |
HasSameMetadataDefinitionAs(MemberInfo) | (Inherited from MemberInfo) |
IsDefined(Type, Boolean) |
Indicates whether an attribute having the specified type is defined on a field. |
IsDefined(Type, Boolean) |
When overridden in a derived class, indicates whether one or more attributes of the specified type or of its derived types is applied to this member. (Inherited from MemberInfo) |
MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
SetConstant(Object) |
Sets the default value of this field. |
SetConstantCore(Object) |
When overridden in a derived class, sets the default value of this field. |
SetCustomAttribute(ConstructorInfo, Byte[]) |
Sets a custom attribute using a specified custom attribute blob. |
SetCustomAttribute(CustomAttributeBuilder) |
Sets a custom attribute using a custom attribute builder. |
SetCustomAttributeCore(ConstructorInfo, ReadOnlySpan<Byte>) |
When overridden in a derived class, sets a custom attribute on this assembly. |
SetMarshal(UnmanagedMarshal) |
Obsolete.
Describes the native marshaling of the field. |
SetOffset(Int32) |
Specifies the field layout. |
SetOffsetCore(Int32) |
When overridden in a derived class, specifies the field layout. |
SetValue(Object, Object) |
Sets the value of the field supported by the given object. (Inherited from FieldInfo) |
SetValue(Object, Object, BindingFlags, Binder, CultureInfo) |
Sets the value of the field supported by the given object. |
SetValue(Object, Object, BindingFlags, Binder, CultureInfo) |
When overridden in a derived class, sets the value of the field supported by the given object. (Inherited from FieldInfo) |
SetValueDirect(TypedReference, Object) |
Sets the value of the field supported by the given object. (Inherited from FieldInfo) |
ToString() |
Returns a string that represents the current object. (Inherited from Object) |
Explicit Interface Implementations
_FieldBuilder.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) |
Maps a set of names to a corresponding set of dispatch identifiers. |
_FieldBuilder.GetTypeInfo(UInt32, UInt32, IntPtr) |
Retrieves the type information for an object, which can then be used to get the type information for an interface. |
_FieldBuilder.GetTypeInfoCount(UInt32) |
Retrieves the number of type information interfaces that an object provides (either 0 or 1). |
_FieldBuilder.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) |
Provides access to properties and methods exposed by an object. |
_FieldInfo.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) |
Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from FieldInfo) |
_FieldInfo.GetType() |
Gets a Type object representing the FieldInfo type. (Inherited from FieldInfo) |
_FieldInfo.GetTypeInfo(UInt32, UInt32, IntPtr) |
Retrieves the type information for an object, which can then be used to get the type information for an interface. (Inherited from FieldInfo) |
_FieldInfo.GetTypeInfoCount(UInt32) |
Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from FieldInfo) |
_FieldInfo.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) |
Provides access to properties and methods exposed by an object. (Inherited from FieldInfo) |
_MemberInfo.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) |
Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from MemberInfo) |
_MemberInfo.GetType() |
Gets a Type object representing the MemberInfo class. (Inherited from MemberInfo) |
_MemberInfo.GetTypeInfo(UInt32, UInt32, IntPtr) |
Retrieves the type information for an object, which can then be used to get the type information for an interface. (Inherited from MemberInfo) |
_MemberInfo.GetTypeInfoCount(UInt32) |
Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from MemberInfo) |
_MemberInfo.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) |
Provides access to properties and methods exposed by an object. (Inherited from MemberInfo) |
ICustomAttributeProvider.GetCustomAttributes(Boolean) |
Returns an array of all of the custom attributes defined on this member, excluding named attributes, or an empty array if there are no custom attributes. (Inherited from MemberInfo) |
ICustomAttributeProvider.GetCustomAttributes(Type, Boolean) |
Returns an array of custom attributes defined on this member, identified by type, or an empty array if there are no custom attributes of that type. (Inherited from MemberInfo) |
ICustomAttributeProvider.IsDefined(Type, Boolean) |
Indicates whether one or more instance of |
Extension Methods
GetCustomAttribute(MemberInfo, Type) |
Retrieves a custom attribute of a specified type that is applied to a specified member. |
GetCustomAttribute(MemberInfo, Type, Boolean) |
Retrieves a custom attribute of a specified type that is applied to a specified member, and optionally inspects the ancestors of that member. |
GetCustomAttribute<T>(MemberInfo) |
Retrieves a custom attribute of a specified type that is applied to a specified member. |
GetCustomAttribute<T>(MemberInfo, Boolean) |
Retrieves a custom attribute of a specified type that is applied to a specified member, and optionally inspects the ancestors of that member. |
GetCustomAttributes(MemberInfo) |
Retrieves a collection of custom attributes that are applied to a specified member. |
GetCustomAttributes(MemberInfo, Boolean) |
Retrieves a collection of custom attributes that are applied to a specified member, and optionally inspects the ancestors of that member. |
GetCustomAttributes(MemberInfo, Type) |
Retrieves a collection of custom attributes of a specified type that are applied to a specified member. |
GetCustomAttributes(MemberInfo, Type, Boolean) |
Retrieves a collection of custom attributes of a specified type that are applied to a specified member, and optionally inspects the ancestors of that member. |
GetCustomAttributes<T>(MemberInfo) |
Retrieves a collection of custom attributes of a specified type that are applied to a specified member. |
GetCustomAttributes<T>(MemberInfo, Boolean) |
Retrieves a collection of custom attributes of a specified type that are applied to a specified member, and optionally inspects the ancestors of that member. |
IsDefined(MemberInfo, Type) |
Indicates whether custom attributes of a specified type are applied to a specified member. |
IsDefined(MemberInfo, Type, Boolean) |
Indicates whether custom attributes of a specified type are applied to a specified member, and, optionally, applied to its ancestors. |
GetMetadataToken(MemberInfo) |
Gets a metadata token for the given member, if available. |
HasMetadataToken(MemberInfo) |
Returns a value that indicates whether a metadata token is available for the specified member. |