C# Constants:

const int MAX_PATH = 260;

VB Constants:

Const MAX_PATH As Integer = 260

Notes:

This is the maximum number of characters, usually including a null terminator, of a standard fully-pathed filename for most Windows API functions that operate on filenames (and a few .NET ones, such as Assembly.LoadFrom). Those that fill a buffer with a filename, such as GetTempFileName, expect a buffer of exactly this length. Some functions, such as CreateFile, can be made to accept longer filenames by using the "\\?\" syntax.

Also there exists several libraries to handle it automatically like Long Path Support API at http://www.abtollc.com/Long-Path.aspx