c# - HttpClient PostAsync Invalid Post Format -

i trying use httpclient's postasync login website; fails , when tracked connection using wireshark found posts data incorrectly

code

var content = new formurlencodedcontent(new[]  {     new keyvaluepair<string, string>("value1", data1),     new keyvaluepair<string, string>("value2", data2),     new keyvaluepair<string, string>("value3", data3) }); 

or

var content = new list<keyvaluepair<string, string>> {     new keyvaluepair<string, string>("value1", data1),      new keyvaluepair<string, string>("value2", data2),      new keyvaluepair<string, string>("value3", data3) }; 

usage

httpclient.postasync(posturi, content) 

expectations

value1=123456&value2=123456&value3=123456 

reality

//it adds strange += makes post fail... value1=123456&value2+=123456&value3+=123456 

i know works:

var values = new list<keyvaluepair<string, string>>();  values.add(new keyvaluepair<string, string>("item1", "value1")); values.add(new keyvaluepair<string, string>("item2", "value2")); values.add(new keyvaluepair<string, string>("item3", "value3"));  using (var content = new formurlencodedcontent(values)) {     client.postasync(posturi, content).result) }