[WebMethod]
    public string CheckParam(EmployeeDto emp)
    {
        return "";
    }

public string CallWebMethod(string webServiceURL, string webMethod, Dictionary<string, object> dicParameters)
    {
        try
        {
            byte[] _requestData = this.CreateHttpRequestData(dicParameters);

            string uri = webServiceURL + "/" + webMethod;
            HttpWebRequest _httpRequest = (HttpWebRequest)HttpWebRequest.Create(uri);


            _httpRequest.Method = "POST";
            _httpRequest.KeepAlive = false;
            _httpRequest.ContentType = "application/x-www-form-urlencoded";

            _httpRequest.ContentLength = _requestData.Length;
            _httpRequest.Timeout = 30000;
            HttpWebResponse _httpResponse = null;
            string _response = string.Empty;

            _httpRequest.GetRequestStream().Write(_requestData, 0, _requestData.Length);
            _httpResponse = (HttpWebResponse)_httpRequest.GetResponse();
            System.IO.Stream _baseStream = _httpResponse.GetResponseStream();
            System.IO.StreamReader _responseStreamReader = new System.IO.StreamReader(_baseStream);
            _response = _responseStreamReader.ReadToEnd();
            _responseStreamReader.Close();

            return _response;
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }

    private byte[] CreateHttpRequestData(Dictionary<string, object> dic)
    {
        StringBuilder _sbParameters = new StringBuilder();
        foreach (string param in dic.Keys)
        {
            _sbParameters.Append(param);//key => parameter name
            _sbParameters.Append('=');
            _sbParameters.Append(dic[param]);//key value
            _sbParameters.Append('&');
        }
        _sbParameters.Remove(_sbParameters.Length - 1, 1);

        UTF8Encoding encoding = new UTF8Encoding();

        return encoding.GetBytes(_sbParameters.ToString());

    }

Dictionary<string, object> pp = new Dictionary<string, object>() {
            { "emp",new EmployeeDto { Id=1250,Name="Yasn"} },

        };

        return CallWebMethod("http://localhost:17411/Student.asmx", "CheckParam", pp);