有没有办法保存的方法在变量后来打电话吗？如果我的方法返回不同类型的？ [英] Is there a way to save a method in a variable then call it later? What if my methods return different types?

问题描述

编辑：谢谢你的答案。我目前的工作就可以了！\

Thank you for the answers. I am currently working on it!!\

我有3个方法，S（）返回字符串，D（）返回双和B（）返回布尔。

I have 3 methods, S() returns string, D() returns double and B() returns bool.

我也有我决定使用哪种方法的变量。
我想做到这一点：

I also have a variable that decides which method I use. I want do this:

    // I tried Func<object> method; but it says D() and B() don't return object.
    // Is there a way to use Delegate method; ? That gives me an eror saying method group is not type System.Delegate
    var method;

    var choice = "D";

    if(choice=="D")
    {
        method = D;
    }
    else if(choice=="B")
    {
        method = B;
    }
    else if(choice=="S")
    {
        method = S;
    }
    else return;

    DoSomething(method); // call another method using the method as a delegate.

    // or instead of calling another method, I want to do:
    for(int i = 0; i < 20; i++){
       SomeArray[i] = method();
    }

这可能吗？

Is this possible?

我看了这个帖子：
的存储的方法，在C＃中
类的成员变量，但我需要存储与不同的返回类型...

I read this post: Storing a Method as a Member Variable of a Class in C# But I need to store methods with different return types...

推荐答案

好了，你可以这样做：

Delegate method;

...
if (choice == "D") // Consider using a switch...
{
    method = (Func<double>) D;
}

然后的DoSomething 会被宣布为刚代表，这还不是特别好的。

Then DoSomething would be declared as just Delegate, which isn't terribly nice.

另外，也可以来包装方法刚刚进行任何转换的委托要求得到返回值对象：

Another alternative would be to wrap the method in a delegate which just performs whatever conversion is required to get the return value as object:

Func<object> method;


...
if (choice == "D") // Consider using a switch...
{
    method = BuildMethod(D);
}

...

// Wrap an existing delegate in another one
static Func<object> BuildMethod<T>(Func<T> func)
{
    return () => func();
}

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