CustomAttributeBuilder Class

Helps build custom attributes.

System.Object
  System.Reflection.Emit.CustomAttributeBuilder

Namespace:  System.Reflection.Emit
Assembly:  mscorlib (in mscorlib.dll)

[ComVisibleAttribute(true)]
[ClassInterfaceAttribute(ClassInterfaceType.None)]
[HostProtectionAttribute(SecurityAction.LinkDemand, MayLeakOnAbort = true)]
public class CustomAttributeBuilder : _CustomAttributeBuilder

The CustomAttributeBuilder type exposes the following members.

  NameDescription
Public methodCustomAttributeBuilder(ConstructorInfo, Object[])Initializes an instance of the CustomAttributeBuilder class given the constructor for the custom attribute and the arguments to the constructor.
Public methodCustomAttributeBuilder(ConstructorInfo, Object[], FieldInfo[], Object[])Initializes an instance of the CustomAttributeBuilder class given the constructor for the custom attribute, the arguments to the constructor, and a set of named field/value pairs.
Public methodCustomAttributeBuilder(ConstructorInfo, Object[], PropertyInfo[], Object[])Initializes an instance of the CustomAttributeBuilder class given the constructor for the custom attribute, the arguments to the constructor, and a set of named property or value pairs.
Public methodCustomAttributeBuilder(ConstructorInfo, Object[], PropertyInfo[], Object[], FieldInfo[], Object[])Initializes an instance of the CustomAttributeBuilder class given the constructor for the custom attribute, the arguments to the constructor, a set of named property or value pairs, and a set of named field or value pairs.
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  NameDescription
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Explicit interface implemetationPrivate method_CustomAttributeBuilder.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers.
Explicit interface implemetationPrivate method_CustomAttributeBuilder.GetTypeInfoRetrieves the type information for an object, which can then be used to get the type information for an interface.
Explicit interface implemetationPrivate method_CustomAttributeBuilder.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1).
Explicit interface implemetationPrivate method_CustomAttributeBuilder.InvokeProvides access to properties and methods exposed by an object.
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Use the CustomAttributeBuilder object returned by the constructor to describe the custom attribute. Associate the CustomAttribute with a builder instance by calling the SetCustomAttribute method on that builder instance. For example, create a CustomAttributeBuilder to describe an instance of AssemblyCultureAttribute by supplying the constructor of AssemblyCultureAttribute and its argument. Then call SetCustomAttribute on an AssemblyBuilder to establish the association.

NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: MayLeakOnAbort. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

The following code sample illustrates the use of 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[] { }));
						   
	
   }

}



.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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