How to POST request using RestSharp in Windows Phone 7
===

I m trying to POST the request using RestSharp client as follows 
I m passing the Auth Code to following function 

    public void ExchangeCodeForToken(string code)
        {
            if (string.IsNullOrEmpty(code))
            {
                OnAuthenticationFailed();
            }
            else
            {
                
                var request = new RestRequest(this.TokenEndPoint, Method.POST);
                request.AddParameter("code", code);
                request.AddParameter("client_id", this.ClientId);
                request.AddParameter("client_secret", this.Secret);
                request.AddParameter("redirect_uri", "urn:ietf:wg:oauth:2.0:oob");
                request.AddParameter("grant_type", "authorization_code");
                request.AddHeader("content-type", "application/x-www-form-urlencoded");

                client.ExecuteAsync<AuthResult>(request, GetAccessToken);
            }
        }

    void GetAccessToken(IRestResponse<AuthResult> response)
        {
            if (response == null || response.StatusCode != HttpStatusCode.OK
                || response.Data == null || string.IsNullOrEmpty(response.Data.access_token))
            {
                OnAuthenticationFailed();
            }
            else
            {
                Debug.Assert(response.Data != null);
                AuthResult = response.Data;
                OnAuthenticated();
            }
        }


But i am getting response.StatusCode = Bad Request. Can anyone help me for how do i POST the request using Restsharp client.