public bool LoginDtBs(string username,string pwd)
        {
            userstr = "User ID=" + username + ";Pwd=" + pwd + ";";
            SqlConnection conn = new SqlConnection(userstr);
            try
            {
                conn.Open();
            }
            catch (Exception e)
            {
                msg = e.Message;
                return false;
            }
            finally
            {
                conn.Close();
            }
            return true;
        }

private string CreateConnectionString()
        {
            if (cbAuthType.SelectedIndex == 1)
            {
                connectionString = string.Empty;
                connectionString += "Data Source=";
                connectionString += txtServer.Text.Trim() + "; ";
                connectionString += "Initial Catalog=master;";
                connectionString += "User Id=";
                connectionString += txtUserName.Text.Trim() + "; ";
                connectionString += "Password=";
                connectionString += txtPassWord.Text.Trim() + "; ";
            }
            else
            {
                connectionString = string.Empty;
                connectionString += "Data Source=" + txtServer.Text.Trim() + ";";
                connectionString += "Initial Catalog=master;Integrated Security=SSPI";
            }
            return connectionString;
        }