CODEWITHSUNDEEP
c#.netdynamicc#-4.0
Morgan Cheng
Morgan Cheng

Reputation: 75998

How to invoke static method in C#4.0 with dynamic type?

In C#4.0, we have dynamic type, but how to invoke static method of dynamic type object?

Below code will generate exception at run time. The dynamic object is from C# class, but it could be object from other languages through DLR. The point is not how to invoke static method, but how to invoke static method of dynamic object which could not be created in C# code.

class Foo
{
    public static int Sum(int x, int y)
    {
        return x + y;
    }
}

class Program
{

    static void Main(string[] args)
    {
        dynamic d = new Foo();
        Console.WriteLine(d.Sum(1, 3));

    }
}

IMHO, dynamic is invented to bridge C# and other programming language. There is some other language (e.g. Java) allows to invoke static method through object instead of type.

BTW, The introduction of C#4.0 is not so impressive compared to C#3.0.

Upvotes: 14

Views: 12397

Answers (3)

jbtule
jbtule

Reputation: 31799

While C# doesn't support it, the DLR does. You can programmatically access the dlr calls with Dynamitey

var staticContext = InvokeContext.CreateStatic ;

Console.WriteLine(Dynamic.InvokeMember(staticContext(typeof(Foo)), "Sum", 1,3));

Upvotes: 10

LukeH
LukeH

Reputation: 269318

One possible workaround would be to use reflection.

dynamic d = new Foo();

var sum = (int)d.GetType()
                .GetMethod("Sum")
                .Invoke(d, new object[] { 1, 3 });
Console.WriteLine(sum);

Upvotes: 7

Julien Lebosquain
Julien Lebosquain

Reputation: 41213

This is not supported directly by C# 4 but there's an interesting workaround in this blog post: http://blogs.msdn.com/davidebb/archive/2009/10/23/using-c-dynamic-to-call-static-members.aspx

Upvotes: 13

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