How to call a C# method only if it exists?

Question

Is this possible without reflection otherwise with reflection ? This is something very often used in PHP like in Wordpress.

Something in pseudo code:

if (exists(object.method)) {object.method}

or

try {object.method} finally {...}

Answer 1

Well, you could declare it in an interface, and then use:

IFoo foo = bar as IFoo;
if (foo != null)
{
    foo.MethodInInterface();
}

That assumes you can make the object's actual type implement the interface though.

Otherwise you'd need to use reflection AFAIK.

(EDIT: The dynamic typing mentioned elsewhere would work on .NET 4 too, of course... but catching an exception for this is pretty nasty IMO.)

Answer 2

You could use dynamics and catch the Runtime exception:

dynamic d = 5;
try
{
    Console.WriteLine(d.FakeMethod(4));
}
catch(RuntimeBinderException)
{
    Console.WriteLine("Method doesn't exist");
}

Although it sounds more like a design problem.

Disclaimer
This code is not for use, just an example that it can be done.

Answer 3

Use .GetType().GetMethod() to check if it exists, and then .Invoke() it.

var fooBar = new FooBarClass();
var method = fooBar.GetType().GetMethod("ExistingOrNonExistingMethod");
if (method != null)
{
    method.Invoke(fooBar, new object[0]);
}

Answer 4

With the dynamic type in C# 4.0, you could do something like this:

dynamic obj = GetDynamicObject();
if (obj != null && obj.GetType().GetMethod("DoSomething") != null)
{
    obj.DoSomething();
}

But the only way to tell if a type has a method in the first place is to use reflection; so the above approach doesn't really buy you anything (you might as well take the MethodInfo you get from calling GetMethod and just Invoke it).

Edit: If you're open to trying to call the method even when it's not there, then Yuriy's answer is probably what you're looking for. My original answer was a literal response to the way you worded your question: "How to call a C# method only if it exists."

Answer 5

I came across this looking for the same answer but did not like any of the solutions.

here is mine:

//Invoke the refresh method if the datasource contains it
if (this.DataSource.GetType().GetMethod("Refresh") != null)
     this.DataSource.GetType().GetMethod("Refresh").Invoke(this.DataSource, new object[] { });

Answer 6

You should revise existance first. MethodInfo[] myArrayMethodInfo = myType.GetMethods();