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Path.GetExtension Method

Returns the extension of the specified path string.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)

public static string GetExtension(
	string path


Type: System.String

The path string from which to get the extension.

Return Value

Type: System.String
The extension of the specified path (including the period "."), or null, or String.Empty. If path is null, GetExtension returns null. If path does not have extension information, GetExtension returns String.Empty.


path contains one or more of the invalid characters defined in GetInvalidPathChars.

The extension of path is obtained by searching path for a period (.), starting with the last character in path and continuing toward the start of path. If a period is found before a DirectorySeparatorChar or AltDirectorySeparatorChar character, the returned string contains the period and the characters after it; otherwise, Empty is returned.

For a list of common I/O tasks, see Common I/O Tasks.

The following code example demonstrates using the GetExtension method on a Windows-based desktop platform.

string fileName = @"C:\mydir.old\myfile.ext";
string path = @"C:\mydir.old\";
string extension;

extension = Path.GetExtension(fileName);
Console.WriteLine("GetExtension('{0}') returns '{1}'", 
    fileName, extension);

extension = Path.GetExtension(path);
Console.WriteLine("GetExtension('{0}') returns '{1}'", 
    path, extension);

// This code produces output similar to the following: 
// GetExtension('C:\mydir.old\myfile.ext') returns '.ext' 
// GetExtension('C:\mydir.old\') returns ''

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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