c# - 代码无法在 Compact Framework 中编译

Question

以下代码无法在 Compact Framework 2 ( VS2008 ) 上编译

public delegate TResult Func<out TResult>();
public delegate TResult Func<in T, out TResult>(T a);
public delegate TResult Func<in T1, in T2, out TResult>(T1 arg1, T2 arg2);
public delegate TResult Func<in T1, in T2, in T3, out TResult>(T1 arg1, T2 arg2, T3 arg3);
public delegate TResult Func<in T1, in T2, in T3, in T4, out TResult>(T1 arg1, T2 arg2, T3 arg3, T4 arg4);

我不确定代码作者的意图是什么，我需要知道如何解决这个问题。

附加信息：此代码来自LinqBridge的源代码

谢谢

Answer 1

该代码只是定义Func了 .NET 2.0 中尚未定义的各种委托，

尝试去掉inandout修饰符，因为 .NET 2.0 也不支持它们：

public delegate TResult Func<TResult>();
public delegate TResult Func<T, TResult>(T a);
public delegate TResult Func<T1, T2, TResult>(T1 arg1, T2 arg2);
public delegate TResult Func<T1, T2, T3, TResult>(T1 arg1, T2 arg2, T3 arg3);
public delegate TResult Func<T1, T2, T3, T4, TResult>(T1 arg1, T2 arg2, T3 arg3, T4 arg4);