FieldBuilder 类
定义并表示字段。无法继承此类。
**命名空间:**System.Reflection.Emit
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
<ClassInterfaceAttribute(ClassInterfaceType.None)> _
<ComVisibleAttribute(True)> _
Public NotInheritable Class FieldBuilder
Inherits FieldInfo
Implements _FieldBuilder
用法
Dim instance As FieldBuilder
[ClassInterfaceAttribute(ClassInterfaceType.None)]
[ComVisibleAttribute(true)]
public sealed class FieldBuilder : FieldInfo, _FieldBuilder
[ClassInterfaceAttribute(ClassInterfaceType::None)]
[ComVisibleAttribute(true)]
public ref class FieldBuilder sealed : public FieldInfo, _FieldBuilder
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */
/** @attribute ComVisibleAttribute(true) */
public final class FieldBuilder extends FieldInfo implements _FieldBuilder
ClassInterfaceAttribute(ClassInterfaceType.None)
ComVisibleAttribute(true)
public final class FieldBuilder extends FieldInfo implements _FieldBuilder
备注
提示
应用于此类的 HostProtectionAttribute 属性 (Attribute) 具有以下 Resources 属性 (Property) 值：MayLeakOnAbort。HostProtectionAttribute 不影响桌面应用程序（这些应用程序通常通过双击图标、键入命令或在浏览器中输入 URL 来启动）。有关更多信息，请参见 HostProtectionAttribute 类或 SQL Server 编程和宿主保护属性。
通过调用 DefineField、DefineInitializedData 或 DefineUninitializedData 来获取 FieldBuilder 的实例。
示例
下面的代码阐释了如何使用 FieldBuilder。
Imports System
Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit
Imports System.Security.Permissions
Public Class FieldBuilder_Sample
Private Shared Function CreateType(currentDomain As AppDomain) As Type
' Create an assembly.
Dim myAssemblyName As New AssemblyName()
myAssemblyName.Name = "DynamicAssembly"
Dim myAssembly As AssemblyBuilder = currentDomain.DefineDynamicAssembly(myAssemblyName, _
AssemblyBuilderAccess.Run)
' Create a dynamic module in Dynamic Assembly.
Dim myModuleBuilder As ModuleBuilder = myAssembly.DefineDynamicModule("MyModule")
' Define a public class named "MyClass" in the assembly.
Dim myTypeBuilder As TypeBuilder = myModuleBuilder.DefineType("MyClass", _
TypeAttributes.Public)
' Define a private String field named "MyField" in the type.
Dim myFieldBuilder As FieldBuilder = myTypeBuilder.DefineField("MyField", _
GetType(String), FieldAttributes.Private Or FieldAttributes.Static)
' Create the constructor.
Dim constructorArgs As Type() = {GetType(String)}
Dim constructor As ConstructorBuilder = _
myTypeBuilder.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, myFieldBuilder)
constructorIL.Emit(OpCodes.Ret)
' Create the MyMethod method.
Dim myMethodBuilder As MethodBuilder = myTypeBuilder.DefineMethod("MyMethod", _
MethodAttributes.Public, GetType(String), Nothing)
Dim methodIL As ILGenerator = myMethodBuilder.GetILGenerator()
methodIL.Emit(OpCodes.Ldarg_0)
methodIL.Emit(OpCodes.Ldfld, myFieldBuilder)
methodIL.Emit(OpCodes.Ret)
Console.WriteLine("Name :" + myFieldBuilder.Name)
Console.WriteLine("DeclaringType :" + myFieldBuilder.DeclaringType.ToString())
Console.WriteLine("Type :" + myFieldBuilder.FieldType.ToString())
Console.WriteLine("Token :" + myFieldBuilder.GetToken().Token.ToString())
Return myTypeBuilder.CreateType()
End Function 'CreateType
<PermissionSetAttribute(SecurityAction.Demand, Name:="FullTrust")> _
Public Shared Sub Main()
Try
Dim myType As Type = CreateType(Thread.GetDomain())
' Create an instance of the "HelloWorld" class.
Dim helloWorld As Object = Activator.CreateInstance(myType, New Object() {"HelloWorld"})
' Invoke the "MyMethod" method of the "MyClass" class.
Dim myObject As Object = myType.InvokeMember("MyMethod", _
BindingFlags.InvokeMethod, Nothing, helloWorld, Nothing)
Console.WriteLine("MyClass.MyMethod returned: " & Microsoft.VisualBasic.Chr(34) & myObject & Microsoft.VisualBasic.Chr(34) )
Catch e as Exception
Console.WriteLine("Exception Caught "+e.Message)
End Try
End Sub 'Main
End Class 'FieldBuilder_Sample
using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
using System.Security.Permissions;
public class FieldBuilder_Sample
{
private static Type CreateType(AppDomain currentDomain)
{
// Create an assembly.
AssemblyName myAssemblyName = new AssemblyName();
myAssemblyName.Name = "DynamicAssembly";
AssemblyBuilder myAssembly =
currentDomain.DefineDynamicAssembly(myAssemblyName,AssemblyBuilderAccess.Run);
// Create a dynamic module in Dynamic Assembly.
ModuleBuilder myModuleBuilder=myAssembly.DefineDynamicModule("MyModule");
// Define a public class named "MyClass" in the assembly.
TypeBuilder myTypeBuilder= myModuleBuilder.DefineType("MyClass",TypeAttributes.Public);
// Define a private String field named "MyField" in the type.
FieldBuilder myFieldBuilder= myTypeBuilder.DefineField("MyField",
typeof(string),FieldAttributes.Private|FieldAttributes.Static);
// Create the constructor.
Type[] constructorArgs = { typeof(String) };
ConstructorBuilder constructor = myTypeBuilder.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, myFieldBuilder);
constructorIL.Emit(OpCodes.Ret);
// Create the MyMethod method.
MethodBuilder myMethodBuilder= myTypeBuilder.DefineMethod("MyMethod",
MethodAttributes.Public,typeof(String),null);
ILGenerator methodIL = myMethodBuilder.GetILGenerator();
methodIL.Emit(OpCodes.Ldarg_0);
methodIL.Emit(OpCodes.Ldfld, myFieldBuilder);
methodIL.Emit(OpCodes.Ret);
Console.WriteLine("Name :"+myFieldBuilder.Name);
Console.WriteLine("DeclaringType :"+myFieldBuilder.DeclaringType);
Console.WriteLine("Type :"+myFieldBuilder.FieldType);
Console.WriteLine("Token :"+myFieldBuilder.GetToken().Token);
return myTypeBuilder.CreateType();
}
[PermissionSetAttribute(SecurityAction.Demand, Name="FullTrust")]
public static void Main()
{
try
{
Type myType = CreateType(Thread.GetDomain());
// Create an instance of the "HelloWorld" class.
Object helloWorld = Activator.CreateInstance(myType, new Object[] { "HelloWorld" });
// Invoke the "MyMethod" method of the "MyClass" class.
Object myObject = myType.InvokeMember("MyMethod",
BindingFlags.InvokeMethod, null, helloWorld, null);
Console.WriteLine("MyClass.MyMethod returned: \"" + myObject + "\"");
}
catch( Exception e)
{
Console.WriteLine("Exception Caught "+e.Message);
}
}
}
using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ CreateType( AppDomain^ currentDomain )
{
// Create an assembly.
AssemblyName^ myAssemblyName = gcnew AssemblyName;
myAssemblyName->Name = "DynamicAssembly";
AssemblyBuilder^ myAssembly = currentDomain->DefineDynamicAssembly( myAssemblyName, AssemblyBuilderAccess::Run );
// Create a dynamic module in Dynamic Assembly.
ModuleBuilder^ myModuleBuilder = myAssembly->DefineDynamicModule( "MyModule" );
// Define a public class named S"MyClass" in the assembly.
TypeBuilder^ myTypeBuilder = myModuleBuilder->DefineType( "MyClass", TypeAttributes::Public );
// Define a private String field named S"MyField" in the type.
FieldBuilder^ myFieldBuilder = myTypeBuilder->DefineField( "MyField", String::typeid, static_cast<FieldAttributes>(FieldAttributes::Private | FieldAttributes::Static) );
// Create the constructor.
array<Type^>^constructorArgs = {String::typeid};
ConstructorBuilder^ constructor = myTypeBuilder->DefineConstructor( MethodAttributes::Public, CallingConventions::Standard, constructorArgs );
ILGenerator^ constructorIL = constructor->GetILGenerator();
constructorIL->Emit( OpCodes::Ldarg_0 );
ConstructorInfo^ superConstructor = Object::typeid->GetConstructor( gcnew array<Type^>(0) );
constructorIL->Emit( OpCodes::Call, superConstructor );
constructorIL->Emit( OpCodes::Ldarg_0 );
constructorIL->Emit( OpCodes::Ldarg_1 );
constructorIL->Emit( OpCodes::Stfld, myFieldBuilder );
constructorIL->Emit( OpCodes::Ret );
// Create the MyMethod method.
MethodBuilder^ myMethodBuilder = myTypeBuilder->DefineMethod( "MyMethod", MethodAttributes::Public, String::typeid, nullptr );
ILGenerator^ methodIL = myMethodBuilder->GetILGenerator();
methodIL->Emit( OpCodes::Ldarg_0 );
methodIL->Emit( OpCodes::Ldfld, myFieldBuilder );
methodIL->Emit( OpCodes::Ret );
Console::WriteLine( "Name : {0}", myFieldBuilder->Name );
Console::WriteLine( "DeclaringType : {0}", myFieldBuilder->DeclaringType );
Console::WriteLine( "Type : {0}", myFieldBuilder->FieldType );
Console::WriteLine( "Token : {0}", myFieldBuilder->GetToken().Token );
return myTypeBuilder->CreateType();
}
int main()
{
try
{
Type^ myType = CreateType( Thread::GetDomain() );
// Create an instance of the S"HelloWorld" class.
array<Object^>^type = {"HelloWorld"};
Object^ helloWorld = Activator::CreateInstance( myType, type );
// Invoke the S"MyMethod" method of the S"MyClass" class.
Object^ myObject = myType->InvokeMember( "MyMethod", BindingFlags::InvokeMethod, nullptr, helloWorld, nullptr );
Console::WriteLine( "MyClass::MyMethod returned: \"{0}\"", myObject );
}
catch ( Exception^ e )
{
Console::WriteLine( "Exception Caught {0}", e->Message );
}
}
继承层次结构
System.Object
System.Reflection.MemberInfo
System.Reflection.FieldInfo
System.Reflection.Emit.FieldBuilder
线程安全
此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。
平台
Windows 98、Windows 2000 SP4、Windows Millennium Edition、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0