Symptoms
When you pass a String data type variable to a Win32 application programming interface (API) as an out parameter, the string that the Win32 function call returns does not change.
Resolution
This problem occurs because you cannot modify Visual Basic .NET, Visual Basic 2005, and Visual C# strings. By default, you cannot change the String class after the String class is created. For more information about the String class, see the “References” section.