Changes the extension of a path string.
Assembly: mscorlib (in mscorlib.dll)
'Declaration Public Shared Function ChangeExtension ( _ path As String, _ extension As String _ ) As String
Parameters
- path
- Type: System.String
The path information to modify. The path cannot contain any of the characters defined in GetInvalidPathChars.
- extension
- Type: System.String
The new extension (with or without a leading period). Specify Nothing to remove an existing extension from path.
Return Value
Type: System.StringThe modified path information.
On Windows-based desktop platforms, if path is Nothing or an empty string (""), the path information is returned unmodified. If extension is Nothing, the returned string contains the specified path with its extension removed. If path has no extension, and extension is not Nothing, the returned path string contains extension appended to the end of path.
| Exception | Condition |
|---|---|
| ArgumentException | path contains one or more of the invalid characters defined in GetInvalidPathChars. |
If neither path nor extension contains a period (.), ChangeExtension adds the period.
The extension parameter can contain multiple periods and any valid path characters, and can be any length. If extension is Nothing, the returned string contains the contents of path with the last period and all characters following it removed.
If extension is an empty string, the returned path string contains the contents of path with any characters following the last period removed.
If path does not have an extension and extension is not Nothing, the returned string contains path followed by extension.
If extension is not Nothing and does not contain a leading period, the period is added.
If path contains a multiple extension separated by multiple periods, the returned string contains the contents of path with the last period and all characters following it replaced by extension. For example, if path is "\Dir1\examples\pathtests.csx.txt" and extension is "cs", the modified path is "\Dir1\examples\pathtests.csx.cs".
It is not possible to verify that the returned results are valid in all scenarios. For example, if path is empty, extension is appended.
For a list of common I/O tasks, see Common I/O Tasks.
The following code example demonstrates a use of the ChangeExtension method.
Imports System Imports System.IO Public Class PathSnippets Public Sub ChangeExtension() Dim goodFileName As String = "C:\mydir\myfile.com.extension" Dim badFileName As String = "C:\mydir\" Dim result As String result = Path.ChangeExtension(goodFileName, ".old") Console.WriteLine("ChangeExtension({0}, '.old') returns '{1}'", goodFileName, result) result = Path.ChangeExtension(goodFileName, "") Console.WriteLine("ChangeExtension({0}, '') returns '{1}'", goodFileName, result) result = Path.ChangeExtension(badFileName, ".old") Console.WriteLine("ChangeExtension({0}, '.old') returns '{1}'", badFileName, result) ' This code produces output similar to the following: ' ' ChangeExtension(C:\mydir\myfile.com.extension, '.old') returns 'C:\mydir\myfile.com.old' ' ChangeExtension(C:\mydir\myfile.com.extension, '') returns 'C:\mydir\myfile.com.' ' ChangeExtension(C:\mydir\, '.old') returns 'C:\mydir\.old'
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role not supported), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.