CODEWITHSUNDEEP
c#ienumerablereflection.emitienumerator
zabulus
zabulus

Reputation: 2513

Dynamically generated class that implements IEnumerator<T> GetEnumerator() and IEnumerator IEnumerable.GetEnumerator()

I have a problem with Reflection.Emit. I want to have dynamically created class, that has simple implementation of ICollection. All methods I've defined fine, instead of next two: public IEnumerator GetEnumerator() & IEnumerator IEnumerable.GetEnumerator() Next code shows what I want to be in my dynamic class:

public class SomeClassThatIsIEnumerable<T> : IEnumerable<T>
{
    public IEnumerator<T> GetEnumerator()
    {...}

    IEnumerator IEnumerable.GetEnumerator()
    {...}

}

This one is output from the Reflector opened my dynamic assembly:

public class SomeClassThatIsIEnumerable<T> : IEnumerable<T>
    {
        public IEnumerator<T> GetEnumerator()
        {
           ...
        }

        IEnumerator GetEnumerator()
        {
           ...
        }
    }

I'm defining my class In such way:

TypeBuilder myType = module.DefineType("myType"...);
myType.AddInterfaceImplementation(typeof(IEnumerable));
myType.AddInterfaceImplementation(typeof(IEnumerable<T>));
myType.AddInterfaceImplementation(typeof(ICollection<T>));
myType.DefineMethodOverride(myDefineGetEnumerator(...),typeof(IEnumerable).GetMethod("GetEnumerator");
myType.DefineMethodOverride(myDefineGetGenericEnumerator(...),typeof(IEnumerable<T>).GetMethod("GetEnumerator);
//Definitions of other ICollection methods
//Define GetEnumerator is looks like this:
MethodBuilder method = myType.DefineMethod("GetEnumerator", MethodAttributes.Final | MethodAttributes.Virtual...)
ILGenerator il = method.GetILGenerator();
// adding opcodes

when I call myType.CreateType TypeLoadException throws with message GetEnumerator method doesn't have implementation. I'm suggesting on problem with IEnumerable.GetEnumerator method, because I had problems in writing it on C#, not even in IL :). Can anyone help me?

Upvotes: 6

Views: 1400

Answers (2)

zabulus
zabulus

Reputation: 2513

Answer is next define of the method

 MethodBuilder myMethod = myType.DefineMethod("System.Collections.IEnumerable.GetEnumerator",
                   MethodAttributes.Private | MethodAttributes.HideBySig |
                MethodAttributes.NewSlot | MethodAttributes.Virtual | 
                MethodAttributes.Final);

It was amazing to me that writing an interface name in the name of the method would be to establish a unique relation with the interface

Upvotes: 1

Paul Ruane
Paul Ruane

Reputation: 38590

It appears you should perhaps be using DefineMethod rather than DefineMethodOverride. There is an example of emitting an explicit interface implementation on MSDN. (I have not taken the time to try it however.)

Upvotes: 3

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