Get folder name from full file path

See DirectoryInfo.Name:

string dirName = new DirectoryInfo(@"c:\projects\roott\wsdlproj\devlop\beta2\text").Name;

Try this

var myFolderName = @"c:\projects\roott\wsdlproj\devlop\beta2\text";
var result = Path.GetFileName(myFolderName);

You could use this:

string path = @"c:\projects\roott\wsdlproj\devlop\beta2\text";
string lastDirectory = path.Split(new char[] { System.IO.Path.DirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries).Last();

I think you want to get parent folder name from file path. It is easy to get. One way is to create a FileInfo type object and use its Directory property.

Example:

FileInfo fInfo = new FileInfo("c:\projects\roott\wsdlproj\devlop\beta2\text\abc.txt");

String dirName = fInfo.Directory.Name;