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CustomAttributeBuilder 类

帮助生成自定义属性。

命名空间: System.Reflection.Emit
程序集: mscorlib(在 mscorlib.dll 中)

[ComVisibleAttribute(true)] 
[ClassInterfaceAttribute(ClassInterfaceType.None)] 
public class CustomAttributeBuilder : _CustomAttributeBuilder
/** @attribute ComVisibleAttribute(true) */ 
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */ 
public class CustomAttributeBuilder implements _CustomAttributeBuilder
ComVisibleAttribute(true) 
ClassInterfaceAttribute(ClassInterfaceType.None) 
public class CustomAttributeBuilder implements _CustomAttributeBuilder
不适用。

说明注意:

应用于此类的 HostProtectionAttribute 属性 (Attribute) 具有以下 Resources 属性 (Property) 值:MayLeakOnAbortHostProtectionAttribute 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

使用由构造函数返回的 CustomAttributeBuilder 对象来描述自定义属性。通过调用某个生成器实例上的 SetCustomAttribute 方法将 CustomAttribute 与该生成器实例相关联。例如,通过提供 AssemblyCultureAttribute 的构造函数及其参数,创建 CustomAttributeBuilder 以描述 AssemblyCultureAttribute 的实例。然后调用 AssemblyBuilder 上的 SetCustomAttribute 以建立关联。

下面的代码阐释了如何使用 CustomAttributeBuilder


using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;


// We will apply this custom attribute to our dynamic type.
public class ClassCreator: Attribute

{
   private string creator;
   public string Creator 
   {
	get
	{
	   return creator;
	}
   }	

   public ClassCreator(string name)
   {
      this.creator = name;
   }

}

// We will apply this dynamic attribute to our dynamic method.
public class DateLastUpdated: Attribute

{
   private string dateUpdated;
   public string DateUpdated
   {
   	get
	{
	   return dateUpdated;
	}
   }

   public DateLastUpdated(string theDate)
   {
	this.dateUpdated = theDate;
   } 

}

class MethodBuilderCustomAttributesDemo

{

   public static Type BuildTypeWithCustomAttributesOnMethod()
   {
	
	AppDomain currentDomain = Thread.GetDomain();
	
	AssemblyName myAsmName = new AssemblyName();
	myAsmName.Name = "MyAssembly";

	AssemblyBuilder myAsmBuilder = currentDomain.DefineDynamicAssembly(
				       myAsmName, AssemblyBuilderAccess.Run);

	ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule("MyModule");

	// First, we'll build a type with a custom attribute attached.

	TypeBuilder myTypeBuilder = myModBuilder.DefineType("MyType",
						TypeAttributes.Public);
	
	Type[] ctorParams = new Type[] { typeof(string) };
	ConstructorInfo classCtorInfo = typeof(ClassCreator).GetConstructor(ctorParams);

	CustomAttributeBuilder myCABuilder = new CustomAttributeBuilder(
						classCtorInfo,
						new object[] { "Joe Programmer" });

	myTypeBuilder.SetCustomAttribute(myCABuilder);

	// Now, let's build a method and add a custom attribute to it.

	MethodBuilder myMethodBuilder = myTypeBuilder.DefineMethod("HelloWorld",
					MethodAttributes.Public,
					null,
					new Type[] { });

	ctorParams = new Type[] { typeof(string) };
	classCtorInfo = typeof(DateLastUpdated).GetConstructor(ctorParams);

	CustomAttributeBuilder myCABuilder2 = new CustomAttributeBuilder(
						classCtorInfo,
						new object[] { DateTime.Now.ToString() });

	myMethodBuilder.SetCustomAttribute(myCABuilder2);

	ILGenerator myIL = myMethodBuilder.GetILGenerator();

	myIL.EmitWriteLine("Hello, world!");
	myIL.Emit(OpCodes.Ret);

	return myTypeBuilder.CreateType();
	
   }

   public static void Main() 
   {

	Type myType = BuildTypeWithCustomAttributesOnMethod();

	object myInstance = Activator.CreateInstance(myType);

	object[] customAttrs = myType.GetCustomAttributes(true);

	Console.WriteLine("Custom Attributes for Type 'MyType':");

	object attrVal = null;

	foreach (object customAttr in customAttrs) 
   	{
	   attrVal = typeof(ClassCreator).InvokeMember("Creator", 
					  BindingFlags.GetProperty,
					  null, customAttr, new object[] { });
	   Console.WriteLine("-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal);
        }

	Console.WriteLine("Custom Attributes for Method 'HelloWorld()' in 'MyType':");

	customAttrs = myType.GetMember("HelloWorld")[0].GetCustomAttributes(true);	

	foreach (object customAttr in customAttrs) 
   	{
	   attrVal = typeof(DateLastUpdated).InvokeMember("DateUpdated", 
					  BindingFlags.GetProperty,
					  null, customAttr, new object[] { });
	   Console.WriteLine("-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal);
        }

	Console.WriteLine("---");

	Console.WriteLine(myType.InvokeMember("HelloWorld",
			  BindingFlags.InvokeMethod,
			  null, myInstance, new object[] { }));
						   
	
   }

}


import System.*;
import System.Threading.*;
import System.Reflection.*;
import System.Reflection.Emit.*;

// We will apply this custom attribute to our dynamic type.
public class ClassCreator extends Attribute
{
    private String creator;

    /** @property 
     */
    public String get_Creator()
    {
        return creator ;
    } //get_Creator

    public ClassCreator(String name) 
    {
        this.creator = name;
    } //ClassCreator
} //ClassCreator

// We will apply this dynamic attribute to our dynamic method.
public class DateLastUpdated extends Attribute
{
    private String dateUpdated;
    /** @property 
     */
    public String get_DateUpdated()
    {
        return dateUpdated ;
    } //get_DateUpdated

    public DateLastUpdated(String theDate) 
    {
        this.dateUpdated = theDate;
    } //DateLastUpdated
} //DateLastUpdated

class MethodBuilderCustomAttributesDemo
{
    public static Type BuildTypeWithCustomAttributesOnMethod() 
    {
        AppDomain currentDomain = System.Threading.Thread.GetDomain();
        AssemblyName myAsmName = new AssemblyName();
        myAsmName.set_Name("MyAssembly");
        AssemblyBuilder myAsmBuilder = currentDomain.DefineDynamicAssembly(
            myAsmName, AssemblyBuilderAccess.Run);
        ModuleBuilder myModBuilder =
            myAsmBuilder.DefineDynamicModule("MyModule");
        // First, we'll build a type with a custom attribute attached.
        TypeBuilder myTypeBuilder = myModBuilder.DefineType(
            "MyType", TypeAttributes.Public);
        Type ctorParams[] = new Type[]{String.class.ToType()};
        ConstructorInfo classCtorInfo = 
            ClassCreator.class.ToType().GetConstructor(ctorParams);
        CustomAttributeBuilder myCABuilder =  
            new CustomAttributeBuilder(classCtorInfo,
            new Object[]{"Joe Programmer"});
        myTypeBuilder.SetCustomAttribute(myCABuilder);

        // Now, let's build a method and add a custom attribute to it.
        MethodBuilder myMethodBuilder = myTypeBuilder.DefineMethod(
            "HelloWorld", MethodAttributes.Public, null, new Type[]{});
        ctorParams = new Type[]{String.class.ToType()};
        classCtorInfo =
            DateLastUpdated.class.ToType().GetConstructor(ctorParams);
        CustomAttributeBuilder myCABuilder2 = new CustomAttributeBuilder(
            classCtorInfo, new Object[]{DateTime.get_Now().ToString()});
        myMethodBuilder.SetCustomAttribute(myCABuilder2);
        ILGenerator myIL = myMethodBuilder.GetILGenerator();
        myIL.EmitWriteLine("Hello, world!");
        myIL.Emit(OpCodes.Ret);      
        return myTypeBuilder.CreateType() ;
    } //BuildTypeWithCustomAttributesOnMethod

    public static void main(String[] args)
    {
        Type myType = BuildTypeWithCustomAttributesOnMethod();      
        Object myInstance = Activator.CreateInstance(myType);      
        Object customAttrs[] = myType.GetCustomAttributes(true);      
        Console.WriteLine("Custom Attributes for Type 'MyType':");      
        Object attrVal = null;
        for (int iCtr=0; iCtr < customAttrs.length; iCtr++) {
            Object customAttr = customAttrs[iCtr];
            attrVal = ClassCreator.class.ToType().InvokeMember
                ("Creator", BindingFlags.GetProperty, null, customAttr,
                new Object[] {});
            Console.WriteLine(
                "-- Attribute: [{0} = \"{1}\"]", customAttr,attrVal);
        }      
        Console.WriteLine(
            "Custom Attributes for Method 'HelloWorld()' in 'MyType':");      
        customAttrs =
            myType.GetMember("HelloWorld")[0].GetCustomAttributes(true);
        for(int iCtr = 0; iCtr < customAttrs.length; iCtr++) {
            Object customAttr = customAttrs[iCtr];
            attrVal = DateLastUpdated.class.ToType().InvokeMember(
                "DateUpdated", BindingFlags.GetProperty, null, 
                customAttr, new Object[] {});
            Console.WriteLine(
                "-- Attribute: [{0} = \"{1}\"]",customAttr, attrVal);
        }      
        Console.WriteLine("---");      
        Console.WriteLine(myType.InvokeMember(
            "HelloWorld", BindingFlags.InvokeMethod, null, 
            myInstance, new Object[] {}));
    } //main
} //MethodBuilderCustomAttributesDemo

System.Object
  System.Reflection.Emit.CustomAttributeBuilder

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。

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

Windows Vista、Microsoft Windows XP SP2 和 Windows Server 2003 SP1 支持 Microsoft .NET Framework 3.0。

.NET Framework

受以下版本支持:3.0、2.0、1.1、1.0

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