使用C#OpCodes发出返回对象的方法 [英] Using C# OpCodes to emit method that returns an object

问题描述

我正在创建一个动态类型，该类型具有一种我想返回一个对象的方法.我不明白如何实现这一目标.这是我到目前为止的内容:

I am creating a dynamic type which has a method that I'd like to return an object. I am failing to understand how to achieve this. Here's what I have so far:

// .. stuff to create type builder



MethodBuilder builder =
                typeBuilder.DefineMethod(
                    method.Name,
                    MethodAttributes.Virtual | MethodAttributes.Public,
                    method.CallingConvention,
                    method.ReturnType,
                    typeArray1);
            builder.InitLocals = true;
ILGenerator gen = builder.GetILGenerator();
Object myObjectIdLikeToReturn = someMethodCall();
//gen.??(??????????) // here's where I'm lost
gen.Emit(OpCodes.Ldloc_0);
gen.Emit(OpCodes.Ret);

我相信，如果我正确地读取了msdn，我需要在堆栈上获取myObjectIdLikeToReturn的引用-但是我还没有走运.谁能指出我正确的方向?

I believe, if I am reading the msdn correct, I need to get the reference of myObjectIdLikeToReturn on the stack--however I've not had luck. Can anyone point me in the right direction?

使其更加清晰.我正在尝试在IL中编写等效项:

To make it more clear. I'm attempting to write the equivalent in IL:

public virtual Object MyNewMethod() {
   return myObjectIdLikeToReturn;
}

推荐答案

您有这行:

Object myObjectIdLikeToReturn = someMethodCall();

您说您希望将对myObjectIdLikeToReturn的引用获取到堆栈中".但这是不可能的.我认为您混淆了这些事情发生的时间. IL生成代码类似于 compiling (编译)-一切都需要静态地了解.而myObjectIdLikeToReturn是在生成代码时碰巧存在的变量，但对实际生成的类没有任何意义.您不能接受"对任意运行时对象的引用，这种想法根本没有任何意义.

You say you "want to get the reference to myObjectIdLikeToReturn onto the stack." But that is impossible. I think you are confusing the timing of when these things are happening. The IL generation code is analogous to compiling -- everything needs to be known statically. Whereas myObjectIdLikeToReturn is a variable that happens to exist while you are generating the code, but would not have any meaning to the class that is actually generated. You can't "bake in" a reference to some arbitrary runtime object, the idea simply doesn't make any sense.

您唯一的解决方案是以某种方式使您的IL执行对someMethodCall的调用.但是，如果不了解该方法的用途以及它与生成的类型的关系，就很难详细说明如何实现该方法.

Your only solution is to somehow make your IL perform the invocation to someMethodCall. But without knowing more about where that method lives and its connection to your generated type, it's hard to elaborate on precisely how you'll accomplish that.

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