If you have ever required a user to enter a file name and had to validate the characters they entered, I'm sure you have some sort of function that can do this. Surprisingly though, I see a bunch of code where people build their own file name character validation functions.
There is a built-in .NET function for validating file naming characters available from the System.IO namespace. The snippet below shows a very basic use of this command accepting an input of a string to validate and returns the same string back out if valid and an empty string if invalid file naming characters are detected.
''' <summary> ''' Make sure the path does not contain any invalid file naming characters ''' </summary> ''' <param name="fileName">The Filename to check</param> ''' <returns>A string</returns> ''' <remarks></remarks> Private Function CheckValidFileName(ByVal fileName As String) As String For Each c In Path.GetInvalidFileNameChars() If fileName.Contains(c) Then ' Invalid filename characters detected... ' Could either replace characters or return empty Return "" End If Next Return fileName End FunctionYou can call this function like:
If CheckValidFileName(m_string) = "" Then Throw New ExceptionIf an empty string is returned, you've got invalid characters in the file name...