The value of the Content-type HTTP header of the current instance. The default value is null .
The HttpWebRequest.ContentType property contains the media type of the request. Values assigned to the HttpWebRequest.ContentType property replace any existing contents when the request sends the Content-type HTTP header.
To clear the Content-type HTTP header, set the HttpWebRequest.ContentType property to null.
The value for this property is stored in System.Net.WebHeaderCollection . If System.Net.WebHeaderCollection is set, the property value is lost.