如何使用私有类型调用方法<T>(Func <Action <T >>操作)

Question

我希望代码剪切说明我的问题.我需要Invoke的CallEvent方法就像它在out-comment线中一样.我到没有访问ThirdParty或AnotherThirdParty类.
就我而言:

public class ThirdParty
{
    private struct MsgType
    { }

    private static void AnotherFunc(MsgType msg)
    { }
}

public class AnotherThirdParty
{
    public static void CallEvent<T>(Func<int, Action<T>> action, T arg)
    { }
}

public class MyClass
{
    public static void Main()
    {
        Type MsgType = typeof(ThirdParty).GetNestedType(
            "MsgType", BindingFlags.Instance | BindingFlags.NonPublic);
        object msg = Activator.CreateInstance(MsgType);

        MethodInfo CallEvent = typeof(AnotherThirdParty).GetMethod("CallEvent");
        CallEvent = CallEvent.MakeGenericMethod(MsgType);

        MethodInfo AnotherFunc = typeof(ThirdParty).GetMethod(
            "AnotherFunc", BindingFlags.Static | BindingFlags.NonPublic);

        CallEvent.Invoke(null, new object[] {???, msg});
        //CallEvent<MsgType>((int x) => new Action<MsgType>(AnotherFunc), msg);
        // I can't get my head around how to solve this (Action<msgtype>)
    }
}

我也尝试过:

CallEvent.Invoke(null, new object[]
    {
        new Func<int, Action<object>>((int x) =>
            new Action<object>((object y) =>
                AnotherFunc.Invoke(null, new object[] { y }))),
        msg
    });

我得到以下例外:

System.ArgumentException:类型为'System.Func2 [System.Int32,System.Action1 [System.Object]]'的对象无法转换为类型'System.Func2 [System.Int32,System.Action1 [ThirdParty + MsgType]].

我该怎么办？

Answer 1

public class ThirdParty
{
    private struct MsgType { }
    private static void AnotherFunc(MsgType msg)
    {
        // Inserted to demonstrate getting here
        Console.WriteLine($"HEY: {msg}");
    }
}

public class AnotherThirdParty
{
    public static void CallEvent<T>(Func<int, Action<T>> action, T arg)
    {
        // Inserted to demonstrate calling the func and then
        // the action
        action(12)(arg);
    }
}

public static void Main()
{
    var msgTypeType = 
        typeof(ThirdParty).GetNestedType("MsgType", BindingFlags.NonPublic);

    // This is the message type we're passing (presumably you'll do more with it)
    var ourMsgTypeArg = Activator.CreateInstance(msgTypeType);

    // Get the reference to the CallEvent method
    var callEventMethod =
        typeof(AnotherThirdParty).GetMethod("CallEvent", BindingFlags.Public | BindingFlags.Static)
        .MakeGenericMethod(msgTypeType);

    // Get the reference to the AnotherFunc method
    var anotherFunc =
        typeof(ThirdParty).GetMethod("AnotherFunc", BindingFlags.NonPublic | BindingFlags.Static);

    // Build the func to pass along to CallEvent
    var func = CreateFunc(msgTypeType, anotherFunc);

    // Call the CallEvent<MsgType> method.
    callEventMethod.Invoke(null, new object[] {
        func,
        ourMsgTypeArg
    });
}

private static Delegate CreateFunc(Type msgType, MethodInfo anotherFunc)
{
    // The func takes an int
    var intArg = Expression.Parameter(typeof(int));

    // The action takes a msgType
    var msgTypeArg = Expression.Parameter(msgType);

    // Represent the call out to "AnotherFunc"
    var call = Expression.Call(null, anotherFunc, msgTypeArg);

    // Build the action to just make the call to "AnotherFunc"
    var action = Expression.Lambda(call, msgTypeArg);

    // Build the func to just return the action
    var func = Expression.Lambda(action, intArg);

    // Compile the chain and send it out
    return func.Compile();
}

此代码按您的要求运行并打印以下内容:

HEY: UserQuery+ThirdParty+MsgType