I'm using C# and providing a callback function to an unmanaged C++
function that uses the callback to send back a character string. It
works find if the string sent through the callback is less than
StringBuilder's default capacity (16 char). If it is greater, then C#
stops and issues a "capacity is greater than maximum capacity" error.

Is there a way to increase the StringBuilder capacity when it's used as
part of the parameter list of a callback function? It's different than a
call to a function like GetWindowText() where you can define the
StringBuilder instance before passing it to GetWindowText. I don't see
where I can preallocate the StringBuilder capacity when the C++ function
calls the callback routine.

Thanks,

Ed

Here's the boiled-down version of the code:

public delegate int MyCallback( StringBuilder stuff );

[DllImport ("MyDll.dll", CharSet=CharSet.Ansi)]
public static extern unsafe int FetchStuff (
            ,MyCallback myCallBack );

private static string myString;

public unsafe static int CallBackFunction(StringBuilder stuff)
{
   string myString = stuff.ToString();
   ...
}

public class Main
{
   MyCallback callBack= new MyCallback (Form1.CallBackFunction);

   int return;
   return = FetchStuff (callBack);
}