How to simulate browser HTTP POST request and capture result in C#

You could take a look at the WebClient class. It allows you to post data to an arbitrary url:

using (var client = new WebClient())
{
    var dataToPost = Encoding.Default.GetBytes("param1=value1&param2=value2");
    var result = client.UploadData("http://example.com", "POST", dataToPost);
    // do something with the result
}

Will generate the following request:

POST / HTTP/1.1
Host: example.com
Content-Length: 27
Expect: 100-continue
Connection: Keep-Alive

param1=value1&param2=value2