C# delegate not bound to an instance?

Question

Is there a way to store a delegate without binding it to an object like how you can with a MethodInfo? Right now I am storing a MethodInfo so I can give it the object to cal

Answer 1

What you want is called an open instance delegate. It isn't supported directly in the C# language, but the CLR supports it.

Basically, an open instance delegate is the same as a normal delegate, but it takes an extra parameter for this before the normal parameters, and has a null target (like a delegate for a static method). For instance, the open instance equivalent of Action would be:

delegate void OpenAction(TThis @this, T arg);

Here's a complete example:

void Main()
{
    MethodInfo sayHelloMethod = typeof(Person).GetMethod("SayHello");
    OpenAction action =
        (OpenAction)
            Delegate.CreateDelegate(
                typeof(OpenAction),
                null,
                sayHelloMethod);

    Person joe = new Person { Name = "Joe" };
    action(joe, "Jack"); // Prints "Hello Jack, my name is Joe"
}

delegate void OpenAction(TThis @this, T arg);

class Person
{
    public string Name { get; set; }

    public void SayHello(string name)
    {
        Console.WriteLine ("Hi {0}, my name is {1}", name, this.Name);
    }
}

Have a look at this article for more details.