HttpListenerResponse.AddHeader(String, String) Method


Adds the specified header and value to the HTTP headers for this response.

 void AddHeader(System::String ^ name, System::String ^ value);
public void AddHeader (string name, string value);
member this.AddHeader : string * string -> unit
Public Sub AddHeader (name As String, value As String)



The name of the HTTP header to set.


The value for the name header.


name is null or an empty string ("").

You are not allowed to specify a value for the specified header.


name or value contains invalid characters.

.NET Framework and .NET Core versions 2.0 - 3.1 only: The length of value is greater than 65,535 characters.


The following code example demonstrates adding a header using this property.

public static void SetExpirationDate(long seconds, HttpListenerResponse response)
    response.AddHeader("Expires", seconds.ToString());
Public Shared Sub SetExpirationDate(ByVal seconds As Long, ByVal response As HttpListenerResponse)
    response.AddHeader("Expires", seconds.ToString())
End Sub


Calling this method is equivalent to calling the Set method on the collection returned by the Headers property.

If the header specified in name does not exist, this method inserts a new header into the Headers property's collection. If name is present in the collection, this method replaces the existing value with value. To add a value to an existing header without replacing the existing value, use the AppendHeader method.

Applies to

See also