CustomAttributeBuilder
Class
Definition
Helps build custom attributes.
[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)]
[System.Runtime.InteropServices.ComVisible(true)]
public class CustomAttributeBuilder : System.Runtime.InteropServices._CustomAttributeBuilder
- Inheritance
-
CustomAttributeBuilder
- Attributes
- Implements
Inherited Members
System.Object
Examples
The following code sample illustrates the use of CustomAttributeBuilder.
using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
// We will apply this custom attribute to our dynamic type.
public ref class ClassCreator: public Attribute
{
private:
String^ creator;
public:
property String^ Creator
{
String^ get()
{
return creator;
}
}
ClassCreator( String^ name )
{
this->creator = name;
}
};
// We will apply this dynamic attribute to our dynamic method.
public ref class DateLastUpdated: public Attribute
{
private:
String^ dateUpdated;
public:
property String^ DateUpdated
{
String^ get()
{
return dateUpdated;
}
}
DateLastUpdated( String^ theDate )
{
this->dateUpdated = theDate;
}
};
Type^ BuildTypeWithCustomAttributesOnMethod()
{
AppDomain^ currentDomain = Thread::GetDomain();
AssemblyName^ myAsmName = gcnew 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 );
array<Type^>^temp6 = {String::typeid};
array<Type^>^ctorParams = temp6;
ConstructorInfo^ classCtorInfo = ClassCreator::typeid->GetConstructor( ctorParams );
array<Object^>^temp0 = {"Joe Programmer"};
CustomAttributeBuilder^ myCABuilder = gcnew CustomAttributeBuilder( classCtorInfo,temp0 );
myTypeBuilder->SetCustomAttribute( myCABuilder );
// Now, let's build a method and add a custom attribute to it.
array<Type^>^temp1 = gcnew array<Type^>(0);
MethodBuilder^ myMethodBuilder = myTypeBuilder->DefineMethod( "HelloWorld", MethodAttributes::Public, nullptr, temp1 );
array<Type^>^temp7 = {String::typeid};
ctorParams = temp7;
classCtorInfo = DateLastUpdated::typeid->GetConstructor( ctorParams );
array<Object^>^temp2 = {DateTime::Now.ToString()};
CustomAttributeBuilder^ myCABuilder2 = gcnew CustomAttributeBuilder( classCtorInfo,temp2 );
myMethodBuilder->SetCustomAttribute( myCABuilder2 );
ILGenerator^ myIL = myMethodBuilder->GetILGenerator();
myIL->EmitWriteLine( "Hello, world!" );
myIL->Emit( OpCodes::Ret );
return myTypeBuilder->CreateType();
}
int main()
{
Type^ myType = BuildTypeWithCustomAttributesOnMethod();
Object^ myInstance = Activator::CreateInstance( myType );
array<Object^>^customAttrs = myType->GetCustomAttributes( true );
Console::WriteLine( "Custom Attributes for Type 'MyType':" );
Object^ attrVal = nullptr;
System::Collections::IEnumerator^ myEnum = customAttrs->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ customAttr = safe_cast<Object^>(myEnum->Current);
array<Object^>^temp3 = gcnew array<Object^>(0);
attrVal = ClassCreator::typeid->InvokeMember( "Creator", BindingFlags::GetProperty, nullptr, customAttr, temp3 );
Console::WriteLine( "-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal );
}
Console::WriteLine( "Custom Attributes for Method 'HelloWorld()' in 'MyType':" );
customAttrs = myType->GetMember( "HelloWorld" )[ 0 ]->GetCustomAttributes( true );
System::Collections::IEnumerator^ myEnum2 = customAttrs->GetEnumerator();
while ( myEnum2->MoveNext() )
{
Object^ customAttr = safe_cast<Object^>(myEnum2->Current);
array<Object^>^temp4 = gcnew array<Object^>(0);
attrVal = DateLastUpdated::typeid->InvokeMember( "DateUpdated", BindingFlags::GetProperty, nullptr, customAttr, temp4 );
Console::WriteLine( "-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal );
}
Console::WriteLine( "---" );
array<Object^>^temp5 = gcnew array<Object^>(0);
Console::WriteLine( myType->InvokeMember( "HelloWorld", BindingFlags::InvokeMethod, nullptr, myInstance, temp5 ) );
}
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[] { }));
}
}
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
Remarks
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.
Constructors
| CustomAttributeBuilder(ConstructorInfo, Object[]) |
Initializes an instance of the |
| CustomAttributeBuilder(ConstructorInfo, Object[], FieldInfo[], Object[]) |
Initializes an instance of the |
| CustomAttributeBuilder(ConstructorInfo, Object[], PropertyInfo[], Object[]) |
Initializes an instance of the |
| CustomAttributeBuilder(ConstructorInfo, Object[], PropertyInfo[], Object[], FieldInfo[], Object[]) |
Initializes an instance of the |
Explicit Interface Implementations
| _CustomAttributeBuilder.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) |
Maps a set of names to a corresponding set of dispatch identifiers. |
| _CustomAttributeBuilder.GetTypeInfo(UInt32, UInt32, IntPtr) |
Retrieves the type information for an object, which can then be used to get the type information for an interface. |
| _CustomAttributeBuilder.GetTypeInfoCount(UInt32) |
Retrieves the number of type information interfaces that an object provides (either 0 or 1). |
| _CustomAttributeBuilder.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) |
Provides access to properties and methods exposed by an object. |