RegisterPrefix Method

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

Registers a WebRequest descendant for the specified URI.

Namespace:  System.Net
Assembly:  System.Http (in System.Http.dll)

static bool RegisterPrefix(
	String^ prefix, 
	IWebRequestCreate^ creator


Type: System..::..String
The complete URI or URI prefix that the WebRequest descendant services.
Type: System.Net..::..IWebRequestCreate
The create method that the WebRequest calls to create the WebRequest descendant.

Return Value

Type: System..::..Boolean
true if registration is successful; otherwise, false.

The RegisterPrefix method registers WebRequest descendants to service requests. WebRequest descendants are typically registered to handle a specific protocol, such HTTP or FTP, but can be registered to handle a request to a specific server or path on a server.

The pre-registered reserve types already registered include the following:

  • http://

  • https://

  • ftp://

  • file://

For more information, see the Create(String) and Create(Uri) methods.

Duplicate prefixes are not allowed. RegisterPrefix returns false if an attempt is made to register a duplicate prefix.


The HttpWebRequest class is registered to service requests for HTTP and HTTPS schemes by default. Attempts to register a different WebRequest descendant for these schemes will fail.