CODEWITHSUNDEEP
c#.netclass
user10483669
user10483669

Reputation: 588

passing unknown class as parameter and trying to run function on it

Using C#, lets say I have these classes:

classZero
classOne
classTwo

class classZero and classOne have a public function named "Hello()".

how can i creat a new function (in any class) that takes a unknown class as a paramenter and then run the function "Hello" on this unknown class, if it exists?

in sebdo code this would look something like this:

function runHelloIfPossible(anyclass aclass):
   if aclass contains function Hello:
      aclass.Hello()

if in my case the anyclass argument where any of classZero or classOne the function Hello would run.

Upvotes: 0

Views: 674

Answers (3)

Pavel Anikhouski
Pavel Anikhouski

Reputation: 23228

You can use type pattern matching with switch statement for that (it's available from C# 7)

public void RunHelloIfPossible(object anyObject)
{
    switch (anyObject)
    {
        case classZero zero:
            zero.Hello();
            break;
        case classOne one:
            one.Hello();
            break;
    }           
}

Example of the usage

RunHelloIfPossible(new classOne());

If both classes implement the same interface (lets say IHello) or base class, the code above can be simplified to

if (anyObject is IHello hello)
{
    hello.Hello();
}

Upvotes: 1

user12912098
user12912098

Reputation:

the key word dynamic can be used, please see below codes.

class Program
{
    static void Main(string[] args)
    {
        var class0 = new ClassZero();
        var class1 = new ClassOne();
        var class2 = new ClassTwo();
        var class3 = new ClassWithoutHello();

        class2.DynamicCall(class0);
        class2.DynamicCall(class3);

        Console.ReadLine();
    }
}

public class ClassZero
{
    public void Hello()
    {
        Console.WriteLine("say hello from Class Zero");
    }
}

public class ClassOne
{
    public void Hello()
    {
        Console.WriteLine("say hello from Class One");
    }
}

public class ClassWithoutHello
{

}

public class ClassTwo
{
    public void DynamicCall(dynamic input)
    {
        Console.WriteLine("calling input from Class Two");

        if ((input is ClassZero) || (input is ClassOne))
        {
            input.Hello();
        }
        else
        {
            Console.WriteLine("this type does NOT support hello method");
        }
    }
}

Upvotes: 1

Ive
Ive

Reputation: 1331

public interface IHello
{
    void Hello();
}

public class Zero: IHello
{
    public void Hello()
    {
    }
//...
}

...

void RunHelloIfPossible(object obj)
{
   if (obj is IHello ih)
   {
      ih.Hello();
   }
}

Upvotes: 1

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