如何使用Func <T,bool> 传入对象？

Question

I want to create IValueConverter that getting function and object (of some kind) and return bool value.

How can I cast function and parameters in runtime?

public object EvaluateByValue(object MyFunc, object parameter)
{
    return MyFunc(parameter);
}

For example:

Func<int,bool> MyIntFunction =  i=>return i%2;int number = 8;
bool IsEvan = (bool)EvaluateByValue(MyIntFunction,8);

and another use can be:

Func<string,bool> MyStringFunction = txt=>txt=="Hello";

bool IsWelcome = (bool)EvaluateByValue(MyStringFunction,"Goodbye");

Is there any way to cast the "Func" method by the parameter type?

Thanks

Answer 1

I would change your method to the following:

public object EvaluateByValue(Delegate MyFunc, params object[] parameters)
{
    return MyFunc.DynamicInvoke(parameters);
}

Answer 2

If the cast is your only problem, perhaps what you're looking for is:

var myFuncDelegate = (Func<object, bool>)parameter;

If you want the Func's parameter type to be the same as the given parameter, you would have to use reflection to cast the delegate and execute it.

Answer 3

Well the minimum amount of change would be:

public object EvaluateByValue(Func<object, object> MyFunc, object parameter)
{
    return MyFunc(parameter);
}

or to allow multiple paramaters:

public object EvaluateByValue(Func<object[], object> MyFunc, params object[] parameter)
{
    return MyFunc(parameter);
}

Although I'm not sure what you're trying to do.

Answer 4

You could do something like this for the function declaration

 static K EvaluateByValue<T, K>(Func<T, K> MyFunc, T parameter)
        {
            return MyFunc(parameter);
        }

T is the parameter type and K is the return type

So, let's say you've got this function you want to pass in

 static string parameterFunction(string param)
        {
            return param + " World!";
        }

you would call it like so

var answer = EvaluateByValue<string, string>(parameterFunction, "Hello");

And answer would be Hello World!