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WebHeaderCollection.IsRestricted Method (String)

Tests whether the specified HTTP header can be set for the request.

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

public:
static bool IsRestricted (
	String^ headerName
)
public static boolean IsRestricted (
	String headerName
)
public static function IsRestricted (
	headerName : String
) : boolean

Parameters

headerName

The header to test.

Return Value

true if the header is restricted; otherwise false.

Exception typeCondition

ArgumentNullException

headerName is a null reference (Nothing in Visual Basic) or Empty.

ArgumentException

headerName contains invalid characters.

The IsRestricted method returns true to indicate that a header is restricted and must be set using properties instead of directly or is set by the system. The restricted headers are:

  • Accept

  • Connection

  • Content-Length

  • Content-Type

  • Date

  • Expect

  • Host

  • If-Modified-Since

  • Range

  • Referer

  • Transfer-Encoding

  • User-Agent

  • Proxy-Connection

The following example checks the IsRestricted property to see if any headers are prohibited from being set.

try
{
   // Create a web request for S"www.msn.com".
   HttpWebRequest^ myHttpWebRequest = dynamic_cast<HttpWebRequest^>(WebRequest::Create( "http://www.msn.com" ));

   // Get the associated response for the above request.
   HttpWebResponse^ myHttpWebResponse = dynamic_cast<HttpWebResponse^>(myHttpWebRequest->GetResponse());

   // Get the headers associated with the response.
   WebHeaderCollection^ myWebHeaderCollection = myHttpWebResponse->Headers;
   for ( int i = 0; i < myWebHeaderCollection->Count; i++ )
   {
      // Check if the first response header is restriced.
      if ( WebHeaderCollection::IsRestricted( dynamic_cast<String^>(myWebHeaderCollection->AllKeys[ i ]) ) )
               Console::WriteLine( "' {0}' is a restricted header", myWebHeaderCollection->AllKeys[ i ] );
      else
               Console::WriteLine( "' {0}' is not a restricted header", myWebHeaderCollection->AllKeys[ i ] );
   }
   myHttpWebResponse->Close();
}
catch ( WebException^ e ) 
{
   Console::WriteLine( "\nWebException is thrown.\nMessage is: {0}", e->Message );
   if ( e->Status == WebExceptionStatus::ProtocolError )
   {
      Console::WriteLine( "Status Code : {0}", (dynamic_cast<HttpWebResponse^>(e->Response))->StatusCode );
      Console::WriteLine( "Status Description : {0}", (dynamic_cast<HttpWebResponse^>(e->Response))->StatusDescription );
      Console::WriteLine( "Server : {0}", (dynamic_cast<HttpWebResponse^>(e->Response))->Server );
   }
}
catch ( Exception^ e ) 
{
   Console::WriteLine( "Exception is thrown. Message is : {0}", e->Message );
}

    try {
        // Create a web request for "www.msn.com".
        HttpWebRequest myHttpWebRequest = (HttpWebRequest)(WebRequest.
            Create("http://www.msn.com"));
        // Get the associated response for the above request.
        HttpWebResponse myHttpWebResponse = (HttpWebResponse)(
            myHttpWebRequest.GetResponse());
        // Get the headers associated with the response.
        WebHeaderCollection myWebHeaderCollection =
            myHttpWebResponse.get_Headers();

        for (int i = 0; i < myWebHeaderCollection.get_Count(); i++) {
            // Check if the first response header is restriced.
            if (WebHeaderCollection.IsRestricted(myWebHeaderCollection.
                get_AllKeys()[i])) {
                Console.WriteLine("'{0}' is a restricted header",
                    myWebHeaderCollection.get_AllKeys()[i]);
            }
            else {
                Console.WriteLine("'{0}' is not a restricted header",
                    myWebHeaderCollection.get_AllKeys().get_Item(i));
            }
        }
        myHttpWebResponse.Close();
    }
    catch (WebException e) {
        Console.WriteLine("\nWebException is thrown.\nMessage is:" 
            + e.get_Message());
        if (e.get_Status().Equals(WebExceptionStatus.ProtocolError)) {
            Console.WriteLine("Status Code : {0}", ((HttpWebResponse)(
                e.get_Response())).get_StatusCode());
            Console.WriteLine("Status Description : {0}", ((
                HttpWebResponse)(e.get_Response())).get_StatusDescription());
            Console.WriteLine("Server : {0}", ((HttpWebResponse)(
                e.get_Response())).get_Server());
        }
    }
    catch (System.Exception e) {
        Console.WriteLine("Exception is thrown. Message is :" 
            + e.get_Message());
    }
} //main

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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