Take a look at this c# bitcoin rpc api wrapper: https://github.com/GeorgeKimionis/BitcoinLib that, unlike bitnet, is up-to-date.

I wrote my own wrapper, it wasn't complicated, this is the basic gist of it below. Adapt for your specific needs.

Example of getting raw transaction

internal static string GetRawTransaction(string txid)
{
    var CredentialCache = new CredentialCache();
    CredentialCache.Add(new Uri("http://127.0.0.1:8332"), "Basic", new NetworkCredential("[your rpc username]", "your rpc password"));

    var httpWebRequest = (HttpWebRequest)WebRequest.Create("http://127.0.0.1:8332");
    httpWebRequest.ContentType = "text/json";
    httpWebRequest.Method = "POST";
    httpWebRequest.Credentials = CredentialCache;

    using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
    {
        string json;
        json = "{ \"jsonrpc\": \"2.0\", \"id\":\"" + Guid.NewGuid().ToString() + "\", \"method\": \"getrawtransaction\",\"params\":[\"" + txid + "\",1]}";

        streamWriter.Write(json);
    }
    var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
    using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
    {
        var responseText = streamReader.ReadToEnd();
        return responseText;
    }
}