带有可选参数的委托引发运行时异常 [英] Delegate with optional parameter throws runtime exception

问题描述

我有这样的代码:

I have code like this:

private delegate string MyDelegate(int requiredParameter, int optionalParameter = -1);
private string MyMethod(int requiredParameter, int optionalParameter = -1)
{
    return "Some return value";
}

然后我这样称呼:

Which I then call like this:

string s = (string)this.Invoke(new MyDelegate(MyMethod), new object[] { 10 });

基于一些 我在StackOverflow上看到，我认为我想做的事情是可能的，但是最后一行抛出TargetParameterCountException和消息Parameter count mismatch.

知道为什么会这样吗?我可以使其以某种比重载更优雅的方式工作吗?

Based on some questions I saw on StackOverflow, I think that what I''m trying to do is possible, but this last line throws a TargetParameterCountException with the message Parameter count mismatch.

Any idea why this happens? Can I make it work in some manner that is more elegant than overloading?

推荐答案

请参考一次:
http://stackoverflow.com/questions/2484226/invoking-eventhandler-generic-targetparametercountexception [ ^ ]

please refer once:
http://stackoverflow.com/questions/2484226/invoking-eventhandler-generic-targetparametercountexception[^]

如果您知道要调用的方法，则

If you know which method you are calling then

string s = (string)this.Invoke(new MyDelegate(MyMethod), new object[] { 10 });

只是没有意义的

is pointless just do

string s = MyMethod(10);

但是，如果您的方法是动态的，则将其设置为

However if your method is dynamic then it would be set somewhere like

private MyDelegate _mydelegate;

public void SetDelegate(MyDelegate del)
{
   _mydelegate = del;
}

你会用
称呼它

and you would call this by

private void somemethod()
{
     string s = _del(10); //using the defined delegate
}

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