Many times in application development using C# it is required to get the directory from a file's full path.

Let us say we need to find the directory for the following path:

   string path = @"C:\Directory\File.txt";

If the requirement is to get the absolute path use the below:

  string absolutePath = Path.GetDirectoryName(path)

If the requirement is to get relative name use the below:

   string relativeName =  FileInfo(path).Directory.FullName.

If the requirement is to get the file name use the below:

string filename = Path.GetFileName(path);

If the requirement is to get the file name without extension use the below:

string filenameNoExtension = Path.GetFileNameWithoutExtension(path);

Note that Path and FileInfo are both found in the namespace System.IO.

We should ensure that path is valid as below:

1) The path parameter should not contain invalid characters, is empty, or contains only white spaces.

2) The path parameter is not longer than the system-defined maximum length.