Du måste ange en begärantext om du anger ContentLength>0 eller SendChunked==true. Gör detta genom att anropa [Begin]GetRequestStream före [Begin]GetResponse.
Click to search this error in Google
English version
You must provide a request body if you set ContentLength>0 or SendChunked==true. Do this by calling [Begin]GetRequestStream before [Begin]GetResponse.
.Net Framework