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WebHeaderCollection.Add Method (String)

.NET Framework 1.1

Inserts the specified header into the collection.

[Visual Basic]
Overloads Public Sub Add( _
   ByVal header As String _
)
[C#]
public void Add(
 string header
);
[C++]
public: void Add(
 String* header
);
[JScript]
public function Add(
   header : String
);

Parameters

header
The header to add, with the name and value separated by a colon.

Exceptions

Exception Type Condition
ArgumentNullException header is a null reference (Nothing in Visual Basic) or Empty.
ArgumentException header does not contain a colon (:) character.

-or-

The name part of header is Empty or contains invalid characters.

-or-

header is a restricted header that should be set with a property.

-or-

The value part of header contains invalid characters.

Remarks

The header parameter must be specified in the format "name:value". If the specified header does not exist in the collection, a new header is added to the collection.

If the header specified in header is already present in the collection, the value part of the header is concatenated with the existing value.

Example

[Visual Basic, C#, C++] The following example adds a name/value pair to a WebHeaderCollection using the Add Method.

[Visual Basic] 
Public Shared Sub Main()

 Try
        'Create a web request for "www.msn.com".
        Dim myHttpWebRequest As HttpWebRequest = CType(WebRequest.Create("http://www.msn.com"), HttpWebRequest)
        
        'Get the headers associated with the request.
        Dim myWebHeaderCollection As WebHeaderCollection = myHttpWebRequest.Headers
        
       Console.WriteLine("Configuring Webrequest to accept Danish and English language using 'Add' method")
        
    'Add the Accept-Language header (for Danish) in the request.
        myWebHeaderCollection.Add("Accept-Language:da")
        
        'Include English in the Accept-Langauge header. 
        myWebHeaderCollection.Add("Accept-Language:en;q" + ChrW(61) + "0.8")
        
        'Get the associated response for the above request.
        Dim myHttpWebResponse As HttpWebResponse = CType(myHttpWebRequest.GetResponse(), HttpWebResponse)
        
        'Print the headers for the request.
        printHeaders(myWebHeaderCollection)
        myHttpWebResponse.Close()
    'Catch exception if trying to add a restricted header.
    Catch e As ArgumentException
        Console.WriteLine(e.Message)
    Catch e As WebException
        Console.WriteLine(e.Message)
        If e.Status = WebExceptionStatus.ProtocolError Then
            Console.WriteLine("Status Code : {0}", CType(e.Response, HttpWebResponse).StatusCode)
            Console.WriteLine("Status Description : {0}", CType(e.Response, HttpWebResponse).StatusDescription)
            Console.WriteLine("Server : {0}", CType(e.Response, HttpWebResponse).Server)
        End If
    Catch e As Exception
        Console.WriteLine(e.Message)
    End Try
End Sub 'Main

[C#] 
try {
    //Create a web request for "www.msn.com".
     HttpWebRequest myHttpWebRequest = (HttpWebRequest) WebRequest.Create("http://www.msn.com");

    //Get the headers associated with the request.
    WebHeaderCollection myWebHeaderCollection = myHttpWebRequest.Headers;

    Console.WriteLine("Configuring Webrequest to accept Danish and English language using 'Add' method");

    //Add the Accept-Language header (for Danish) in the request.
    myWebHeaderCollection.Add("Accept-Language:da");

    //Include English in the Accept-Langauge header. 
    myWebHeaderCollection.Add("Accept-Language:en;q=0.8");

    //Get the associated response for the above request.
     HttpWebResponse myHttpWebResponse = (HttpWebResponse) myHttpWebRequest.GetResponse();

    //Print the headers for the request.
    printHeaders(myWebHeaderCollection);
    myHttpWebResponse.Close();
}
//Catch exception if trying to add a restricted header.
catch(ArgumentException e) {
    Console.WriteLine(e.Message);
}
catch(WebException e) {
    Console.WriteLine("\nWebException is thrown. \nMessage is :" + e.Message);
    if(e.Status == WebExceptionStatus.ProtocolError) {
        Console.WriteLine("Status Code : {0}", ((HttpWebResponse)e.Response).StatusCode);
        Console.WriteLine("Status Description : {0}", ((HttpWebResponse)e.Response).StatusDescription);
        Console.WriteLine("Server : {0}", ((HttpWebResponse)e.Response).Server);
    }
}
catch(Exception e) {
    Console.WriteLine("Exception is thrown. Message is :" + e.Message);
}

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

   //Get the headers associated with the request.
   WebHeaderCollection* myWebHeaderCollection = myHttpWebRequest->Headers;

   Console::WriteLine(S"Configuring Webrequest to accept Danish and English language using 'Add' method");

   //Add the Accept-Language header (for Danish) in the request.
   myWebHeaderCollection->Add(S"Accept-Language:da");

   //Include English in the Accept-Langauge header.
   myWebHeaderCollection->Add(S"Accept-Language:en;q=0.8");

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

   //Print the headers for the request.
   printHeaders(myWebHeaderCollection);
   myHttpWebResponse->Close();
}
//Catch exception if trying to add a restricted header.
catch(ArgumentException* e) {
   Console::WriteLine(e->Message);
} catch (WebException* e) {
   Console::WriteLine(S"\nWebException is thrown. \nMessage is : {0}", e->Message);
   if (e->Status == WebExceptionStatus::ProtocolError) {
      Console::WriteLine(S"Status Code : {0}", 
         __box((dynamic_cast<HttpWebResponse*>(e->Response))->StatusCode));
      Console::WriteLine(S"Status Description : {0}", 
         (dynamic_cast<HttpWebResponse*>(e->Response))->StatusDescription);
      Console::WriteLine(S"Server : {0}", 
         (dynamic_cast<HttpWebResponse*>(e->Response))->Server);
   }
} catch (Exception* e) {
   Console::WriteLine(S"Exception is thrown. Message is : {0}", e->Message);
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

WebHeaderCollection Class | WebHeaderCollection Members | System.Net Namespace | WebHeaderCollection.Add Overload List

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