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.NET Framework Class Library
HttpListenerRequest..::.UrlReferrer Property

Gets the Uniform Resource Identifier (URI) of the resource that referred the client to the server.

Namespace: System.Net
Assembly: System (in System.dll)
Syntax
Public ReadOnly Property UrlReferrer As Uri
public Uri UrlReferrer { get; }
public:
property Uri^ UrlReferrer {
	Uri^ get ();
}
member UrlReferrer : Uri

Property Value

Type: System..::.Uri
A Uri object that contains the text of the request's Referer header, or nullNothingnullptra null reference (Nothing in Visual Basic) if the header was not included in the request.
Remarks

If a client has followed a hyperlink to the requested URI, its request might contain a Referrer header that identifies the URI of the resource that contained the hyperlink.

Clients can falsify or choose not to present a Referer header. Therefore, while the UrlReferrer property can be useful for identifying basic trends in Web traffic; you should not use it as part of an authorization scheme to control access to data.

For a complete list of request headers, see the HttpRequestHeader enumeration.

The UrlReferrer is null when there is no Referrer header in the request or when the Referrer header is present in the request but does not parse to a valid Uri.

Examples

The following code example demonstrates using this property.


Public Shared Sub ShowRequestProperties1(ByVal request As HttpListenerRequest)
    ' Display the MIME types that can be used in the response.
    Dim types() As String = request.AcceptTypes
    If types IsNot Nothing Then
        Console.WriteLine("Acceptable MIME types:")
        For Each s As String In types
            Console.WriteLine(s)
        Next s
    End If
    ' Display the language preferences for the response.
    types = request.UserLanguages
    If types IsNot Nothing Then
        Console.WriteLine("Acceptable natural languages:")
        For Each l As String In types
            Console.WriteLine(l)
        Next l
    End If

    ' Display the URL used by the client.
    Console.WriteLine("URL: {0}", request.Url.OriginalString)
    Console.WriteLine("Raw URL: {0}", request.RawUrl)
    Console.WriteLine("Query: {0}", request.QueryString)

    ' Display the referring URI.
    Console.WriteLine("Referred by: {0}", request.UrlReferrer)

    'Display the HTTP method.
    Console.WriteLine("HTTP Method: {0}", request.HttpMethod)
    'Display the host information specified by the client;
    Console.WriteLine("Host name: {0}", request.UserHostName)
    Console.WriteLine("Host address: {0}", request.UserHostAddress)
    Console.WriteLine("User agent: {0}", request.UserAgent)
End Sub


public static void ShowRequestProperties1 (HttpListenerRequest request)
{
    // Display the MIME types that can be used in the response.
    string[] types = request.AcceptTypes;
    if (types != null)
    {
        Console.WriteLine("Acceptable MIME types:");
        foreach (string s in types)
        {
            Console.WriteLine(s);
        }
    }
    // Display the language preferences for the response.
    types = request.UserLanguages;
    if (types != null)
    {
        Console.WriteLine("Acceptable natural languages:");
        foreach (string l in types)
        {
            Console.WriteLine(l);
        }
    }

    // Display the URL used by the client.
    Console.WriteLine("URL: {0}", request.Url.OriginalString);
    Console.WriteLine("Raw URL: {0}", request.RawUrl);
    Console.WriteLine("Query: {0}", request.QueryString);

    // Display the referring URI.
    Console.WriteLine("Referred by: {0}", request.UrlReferrer);

    //Display the HTTP method.
    Console.WriteLine("HTTP Method: {0}", request.HttpMethod);
    //Display the host information specified by the client;
    Console.WriteLine("Host name: {0}", request.UserHostName);
    Console.WriteLine("Host address: {0}", request.UserHostAddress);
    Console.WriteLine("User agent: {0}", request.UserAgent);
}

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), 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.