如果我有一个封闭泛型类型一个MethodInfo的是有一个简单的方法来切换那些类型？ [英] If I have a MethodInfo on a closed generic Type is there an easy way to switch those types?

问题描述

让我们说，我有MethodInfo的东西像可空< INT> .HasValue 。
反正是有其转换为可空<串> .HasValue

Let's say that I have the methodInfo for something like Nullable<int>.HasValue. Is there anyway to convert it to Nullable<string>.HasValue?

我知道了定期泛型方法我可以做 methodInfo.GetGenericMethod（），但我没有看到一个办法做到这一点从方法的类型，没有做更多的思考开销。如果我已经有方法，为什么我要再次体现？

I know for a regular generic method I can do methodInfo.GetGenericMethod() but I don't see a way to do it for the type from the method, without doing more reflection overhead. If I already have the method why do I have to reflect again?

有趣的是这些方法都具有相同的 MetadataToken ，这使得它更令人印象深刻，不知怎的，Module.ResolveMember似乎右拉一出。

Interestingly enough the methods all have the same MetadataToken, which makes it more impressive that somehow Module.ResolveMember seems to pull the right one out.

有没有办法用 Module.ResolveMethod 来做到这一点？本质上，该方法和类型可以都具有通用的参数，以及我可能需要切换。由于MethodInfo的总是说，它的令牌是相同的令牌代表的MethodInfo是最开放的版本的方法。我只是需要好歹它转换为我喜欢的类型。

Is there any way to do this with the Module.ResolveMethod? Essentially, the method and type may both have generic parameters, and I may need to switch them. Since the MethodInfo always says its token is the same and the token represents the MethodInfo is the most open version of the method. I just need someway for it to be converted to my type.

编辑：
更多的挖掘，似乎这样的事情名单，LT ; T>。新增，列表< INT>。新增的元数据标记我从中获取实际生活我的模块中，而通用定义生活在不同的模块。

More digging, it appears that for something like List<T>.Add, List<int>.Add metadata token from which i retrieve is actually living in my module, while the generic definition lives in a different module.

我真的不希望，一旦我找回员有一次，因为它是非常难以解决被调用的确切同样的方法做反思。

I really don't want to do reflection once I retrieve the member once, as it's very difficult to resolve the exact same method being invoked.

好吧，也许我只是愚蠢，但到底为什么这是否不工作：

Okay maybe I'm just stupid, but why exactly does this not work::

var methodinfo = typeof(List<int>).GetMethod("Add");
var handle = methodinfo.MetaDataToken;
var methodinfo2 = methodinfo.Module.ResolveMethod(handle,new []{typeof(string)},null);

为什么methodInfo2说，这是添加（T），而不是添加（字符串）？

推荐答案

可以做一个符合 MethodBase.GetMethodFromHandle ，但为了使用这种方法，你就必须通过的typeof（名单<串>）而不仅仅是 typeof运算（字符串）。

You can do it in one line with MethodBase.GetMethodFromHandle but in order to use this method you'll have to pass typeof(List<string>) not just typeof(string).

var methodinfo = typeof(List<int>).GetMethod("Add");
var methodinfo2 = MethodBase.GetMethodFromHandle(methodinfo.MethodHandle,
                                                 typeof (List<string>).TypeHandle);

Console.WriteLine(methodinfo);
Console.WriteLine(methodinfo2);

这链路包括上面的示例，为什么 ResolveMethod 不起作用。

This link includes the above sample and an exlpanation of why ResolveMethod doesn't work.

的https://www.re-motion.org/blogs/mix/archive/2009/08/12/试图对解决同一个法-IN-A-封闭仿制type.aspx

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