代表一个动作<参考 T1，T2> [英] Delegate for an Action&lt; ref T1, T2&gt;

问题描述

我正在尝试创建一个采用 ref 参数的静态方法的委托.请不要问我为什么要做这样的 cockamamie 事情.这都是学习 .Net、C# 和反射如何工作以及如何优化它的一部分.

I'm trying to create a delegate of a static method which takes a ref argument. Please don't ask why I'm doing such a cockamamie thing. It's all part of learning how .Net, C#, and reflection work and how to optimize it.

我的代码是:

    public struct DataRow
    {

        private double t;
        static public void Cram_T(ref DataRow dr, double a_t)
        {
            dr.t = a_t;
        }
    }
 ''''
  Type myType = typeof(DataRow);
  MethodInfo my_Cram_T_Method = myType.GetMethod("Cram_T");
  var myCram_T_Delegate = 
         Delegate.CreateDelegate(typeof(Action<DataRow, Double>),      
                                 my_Cram_T_Method) 
                                 as Action<DataRow, Double>;

这给了我一个绑定错误，因为(我认为)通用操作与方法不匹配.

This gives me a binding error because (I think) the generic action doesn't match the method.

在监视窗口中检查 Cram_T_Method 的值给出

Inspecting the value of Cram_T_Method in the watch window gives

{Void Cram_T(DataRow ByRef, Double)}

然后我尝试在 Action 中使用 ref 关键字:

I then tried using the ref keyword in the Action:

  var myCram_T_Delegate = 
         Delegate.CreateDelegate(typeof(Action<ref DataRow, Double>),         
                                 my_Cram_T_Method) 
                                 as Action<ref DataRow, Double>;

但这不会编译.C# 编译器在标记ref"处窒息.

But this won't compile. The C# compiler chokes at the token "ref".

创建此委托的正确方法是什么?

What is the right way to create this delegate?

推荐答案

创建自己的委托类型:

delegate void MyAction(ref DataRow dataRow, double doubleValue);

并使用 MyAction 代替 Action<ref DataRow, Double> - 正如您所指出的那样，它不会编译.

And use MyAction in place of Action<ref DataRow, Double> -- which, as you've noted, doesn't compile.

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