一个方法可以使用预定义的参数附加到代理？ [英] Can a method be attached to a delegate with predefined parameters?

问题描述

有时候我遇到一些情况，我必须将一个方法附加到一个委托人，但是签名不匹配，就像试图将abc附加到某个字符串参数为hi。

  public class test 
 {
 // ... 
 public void abc（int i，string x）
 {
 //做某事
} 
 // ... 
} 
 public class test2 
 {
 somedelegate x; 
 // ... 
 public test2（）
 {
 // Do Something 
 test y = new test（）; 
 x + = y.abc（，嗨）; 
} 
委托void somedelegate（int i）; 
} 
  

我可以使用正确的签名创建另一个代理，然后附加它但它似乎是不必要的复杂。你可以在C＃中做这样的事情吗？谢谢。

对。我想没有办法像我预想的那样做，但是我仍然可以像x + =（int i）=> abc（i，hi）;.所以现在没有问题，谢谢你们。

解决方案

是的，你可以用闭包来实现 p>

[在msdn上有一个很好的对待主题，但像其他任何东西都很难找到）

大图

• 编写一个可以使用您需要的所有参数的方法


• 您返回具有委托目标签名的匿名方法


• 此方法的调用本身就是代理实例化中的参数

是的，这是一个矩阵y。但是方式很酷。

  delegate void somedelegate（int i）; 
 
 protected somedelegate DelegateSignatureAdapter（string b，bool yesOrNo，...）{
 //这个参数是本地方法，所以我们去吧。 
 
 //我们的目标委托需要一个单一的int参数，void return 
 return（int a）=> {
 //您的自定义代码在这里
 //所有调用的争议都在范围内 - 根据需要使用它们
 
}; //不要忘记分号！ 
} 
 
 //我们的委托调用
 somedelegate myWarpedDelegate = new somedelegate（DelegateSignatureAdapter（someString，true））; 
 myWarpedDelegate（2543）; 
 myWarpedDelegate（15）; 
  

Sometimes I encounter cases where I have to attach a method to a delegate but the signature doesn't match, like trying to attach abc down there to somedelegate with the string parameter being "hi".

public class test
{
   //...
   public void abc(int i, string x)
   {
      //Do Something
   }
   //...
}
public class test2
{
   somedelegate x;
   //...
   public test2()
   {
      //Do Something
      test y = new test();
      x += y.abc(,"hi");
   }
   delegate void somedelegate(int i);
}

I can work it around by creating another delegate with the correct signature then attaching it but it seems so unnecessarily complex. Can you do something like this in C#? Thanks.

Right. I guess there is no way to do it as I envisioned but I can still do it simply like x += (int i) => abc(i, "hi");. So no problem now and thanks guys.

解决方案

Yes, you can do this with closures

[there's a nice treatment of the subject on msdn, but like anything else in there it's hard to find]

The Big Picture

• Write a method that can take all the parameters you need
• Inside that method you return an anonymous method with the delegate-target signature it requires
• This method's call is itself the parameter in the delegate instantiation

Yes, this is a bit Matrix-y. But way cool.

delegate void somedelegate (int i);

protected somedelegate DelegateSignatureAdapter ( string b, bool yesOrNo, ...) {
    // the parameters are local to this method, so we'll go w/ that.

    // our target delegate requires a single int parameter and void return
    return  (int a) => {
                // your custom code here
                // all calling arguements are in scope - use them as needed

    };  // don't forget the semicolon!
}

// our delegate call
somedelegate myWarpedDelegate = new somedelegate (DelegateSignatureAdapter("someString", true));
myWarpedDelegate (2543);
myWarpedDelegate(15);

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