CustomAttributeBuilder Class
Assembly: mscorlib (in mscorlib.dll)
'Declaration <ComVisibleAttribute(True)> _ <ClassInterfaceAttribute(ClassInterfaceType.None)> _ Public Class CustomAttributeBuilder Implements _CustomAttributeBuilder 'Usage Dim instance As CustomAttributeBuilder
/** @attribute ComVisibleAttribute(true) */ /** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */ public class CustomAttributeBuilder implements _CustomAttributeBuilder
ComVisibleAttribute(true) ClassInterfaceAttribute(ClassInterfaceType.None) public class CustomAttributeBuilder implements _CustomAttributeBuilder
Note |
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| The HostProtectionAttribute attribute applied to this class 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. |
Use the CustomAttributeBuilder object returned by the constructor to describe the custom attribute. Associate the CustomAttribute to 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.
The following code sample illustrates the use of CustomAttributeBuilder.
Imports System Imports System.Threading Imports System.Reflection Imports System.Reflection.Emit _ ' We will apply this custom attribute to our dynamic type. Public Class ClassCreator Inherits Attribute Private creator As String Public ReadOnly Property GetCreator() As String Get Return creator End Get End Property Public Sub New(name As String) Me.creator = name End Sub 'New End Class 'ClassCreator _ ' We will apply this dynamic attribute to our dynamic method. Public Class DateLastUpdated Inherits Attribute Private dateUpdated As String Public ReadOnly Property GetDateUpdated() As String Get Return dateUpdated End Get End Property Public Sub New(theDate As String) Me.dateUpdated = theDate End Sub 'New End Class 'DateLastUpdated _ Class MethodBuilderCustomAttributesDemo Public Shared Function BuildTypeWithCustomAttributesOnMethod() As Type Dim currentDomain As AppDomain = Thread.GetDomain() Dim myAsmName As New AssemblyName() myAsmName.Name = "MyAssembly" Dim myAsmBuilder As AssemblyBuilder = currentDomain.DefineDynamicAssembly(myAsmName, _ AssemblyBuilderAccess.Run) Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyModule") ' First, we'll build a type with a custom attribute attached. Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("MyType", _ TypeAttributes.Public) Dim ctorParams() As Type = {GetType(String)} Dim classCtorInfo As ConstructorInfo = GetType(ClassCreator).GetConstructor(ctorParams) Dim myCABuilder As New CustomAttributeBuilder(classCtorInfo, _ New Object() {"Joe Programmer"}) myTypeBuilder.SetCustomAttribute(myCABuilder) ' Now, let's build a method and add a custom attribute to it. Dim myMethodBuilder As MethodBuilder = myTypeBuilder.DefineMethod("HelloWorld", _ MethodAttributes.Public, Nothing, New Type() {}) ctorParams = New Type() {GetType(String)} classCtorInfo = GetType(DateLastUpdated).GetConstructor(ctorParams) Dim myCABuilder2 As New CustomAttributeBuilder(classCtorInfo, _ New Object() {DateTime.Now.ToString()}) myMethodBuilder.SetCustomAttribute(myCABuilder2) Dim myIL As ILGenerator = myMethodBuilder.GetILGenerator() myIL.EmitWriteLine("Hello, world!") myIL.Emit(OpCodes.Ret) Return myTypeBuilder.CreateType() End Function 'BuildTypeWithCustomAttributesOnMethod Public Shared Sub Main() Dim myType As Type = BuildTypeWithCustomAttributesOnMethod() Dim myInstance As Object = Activator.CreateInstance(myType) Dim customAttrs As Object() = myType.GetCustomAttributes(True) Console.WriteLine("Custom Attributes for Type 'MyType':") Dim attrVal As Object = Nothing Dim customAttr As Object For Each customAttr In customAttrs attrVal = GetType(ClassCreator).InvokeMember("GetCreator", _ BindingFlags.GetProperty, _ Nothing, customAttr, New Object() {}) Console.WriteLine("-- Attribute: [{0} = ""{1}""]", customAttr, attrVal) Next customAttr Console.WriteLine("Custom Attributes for Method 'HelloWorld()' in 'MyType':") customAttrs = myType.GetMember("HelloWorld")(0).GetCustomAttributes(True) For Each customAttr In customAttrs attrVal = GetType(DateLastUpdated).InvokeMember("GetDateUpdated", _ BindingFlags.GetProperty, _ Nothing, customAttr, New Object() {}) Console.WriteLine("-- Attribute: [{0} = ""{1}""]", customAttr, attrVal) Next customAttr Console.WriteLine("---") Console.WriteLine(myType.InvokeMember("HelloWorld", BindingFlags.InvokeMethod, _ Nothing, myInstance, New Object() {})) End Sub 'Main End Class 'MethodBuilderCustomAttributesDemo
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
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
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
Note