WebHeaderCollection.Add Method (String, String)


The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

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

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

public override void Add(
	string name,
	string value


Type: System.String

The header to add to the collection.

Type: System.String

The content of the header.

Exception Condition

name is null, Empty, or contains invalid characters.


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


value contains invalid characters.


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.

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.

	//Include English in the Accept-Langauge header. 

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

	//Print the headers for the request.
//Catch exception if trying to add a restricted header.
catch(ArgumentException e) {
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);

.NET Framework
Available since 1.1
Return to top