将IEnumerable转换为IEnumerable T用反射 [英] Casting an IEnumerable to IEnumerable<T> with reflection

问题描述

因此，我需要调用第三方方法，该方法具有这样的签名

So, I need to call a third party method, that has a signature like this

ThirdPartyMethod<T>(IEnumerable<T> items)

我的问题是我在编译时不知道对象的类型.

My problem is I don't know the type of my object at compile time.

在编译时我有这个

IEnumerable myObject;
Type typeOfEnumerableIHave;

Sooo ..反射可以以某种方式帮助我吗?

Sooo..can reflection help me out here somehow?

为简单起见，假装我有一个像这样的方法

for simplicity sake, pretend I have a method like this

void DoWork(IEnumerable items, Type type)
{
   //In here I have to call ThirdPartyMethod<T>(IEnumerable<T> items);
}

推荐答案

由于具有IEnumerable myObject;和像ThirdPartyMethod<T>(IEnumerable<T> items)这样的签名，因此可以使用Cast():

Since you have IEnumerable myObject; and signature like ThirdPartyMethod<T>(IEnumerable<T> items) you are able to use Cast():

ThirdPartyMethod(myObject.Cast<T>())

如果在编译时不知道T类型，则应在运行时提供它.

If you don't know the T type at the compile time you should provide it at runtime.

考虑您的第三方库如下

public static class External
{
    public static void ThirdPartyMethod<T>(IEnumerable<T> items)
    {
        Console.WriteLine(typeof(T).Name);
    }
}

如果您关注

Type theType = typeof(int); 
IEnumerable myObject = new object[0];

您可以在运行时获取通用方法ThirdPartyMethod和Cast

you can get generic methods ThirdPartyMethod and Cast at the runtime

var targetMethod = typeof(External).GetMethod("ThirdPartyMethod", BindingFlags.Static | BindingFlags.Public);
var targetGenericMethod = targetMethod.MakeGenericMethod(new Type[] { theType });

var castMethod = typeof(Enumerable).GetMethod("Cast", BindingFlags.Static | BindingFlags.Public);
var caxtGenericMethod = castMethod.MakeGenericMethod(new Type[] { theType });

最后，您调用方法:

targetGenericMethod.Invoke(null, new object[] { caxtGenericMethod.Invoke(null, new object[] { myObject }) });

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