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WebHeaderCollection.Add Method (String, String)

Inserts a header with the specified name and value into the collection.

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

'Declaration
Public Overrides Sub Add ( _
	name As String, _
	value As String _
)
'Usage
Dim instance As WebHeaderCollection
Dim name As String
Dim value As String

instance.Add(name, value)
public void Add (
	String name, 
	String value
)
public override function Add (
	name : String, 
	value : String
)

Parameters

name

The header to add to the collection.

value

The content of the header.

Exception typeCondition

ArgumentException

name is a null reference (Nothing in Visual Basic), Empty, or contains invalid characters.

-or-

name is a restricted header that must be set with a property setting.

-or-

value contains invalid characters.

ArgumentOutOfRangeException

The length of value is greater than 65535.

If the header specified in name does not exist, the Add method inserts a new header into the list of header name/value pairs.

If the header specified in name is already present, value is added to the existing comma-separated list of values associated with name.

The following example adds a name/value pair to a WebHeaderCollection using the Add Method.

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

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.
        get_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.get_Message());
}
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());
}

Windows 98, Windows 2000 SP4, Windows Millennium Edition, 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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