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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 _
)

Parameters

name
Type: System.String

The header to add to the collection.

value
Type: System.String

The content of the header.

ExceptionCondition
ArgumentException

name is Nothing, 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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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