Question

I’m trying to use

public static string TryGetRequestValue(this HttpRequest stringArg, int maxLengthArg)
{
    return null;
}

As an extension method and it isn’t working I get the error message ‘No overload for method TryGetRequestValue’ etc etc…

However when I take out the HttpRequest arg and change it to a string it works….Why is this?

Any help much appreciated.

Answer 1

See my comment under the question, but based on this statement:

However when I take out the
HttpRequest arg and change it to a
string it works….Why is this?

The first parameter in an extension method – the one prefixed with this – determines the type being extended. So the expected way to call this method would be:

HttpRequest instanceOfClassBeingExtended = new HttpRequest();
string returnValue = instanceOfClassBeingExtended.TryGetRequestValue(10000);

The method returns a string, and only takes one parameter: maxLengthArg.

Apologies if you already know this much – posting the code that’s throwing the exception, as well as the exception itself, will make that clearer.