在datagrid中显示UserID

Question

我的用户活动日志中有问题。在SQL中，我将用户的UserID放在User_Activity_Log中，但是当我运行代码时，该UserID始终显示0作为UserID。

string Login = "Login";
Main code = new Main();
string SqlUserID = "SELECT UserID FROM tblUser WHERE Username='" + Convert.ToString(bunifuMaterialTextbox1.Text) + "'AND Password'" + Convert.ToString(bunifuMaterialTextbox2.Text) + "'";
UserID = code.Converter_string(SqlUserID).ToString();
if (UserID != "")
{
      string SqlLoginName = "SELECT Username FROM tblUser WHERE UserID='" + Convert.ToString(UserID) + "'";
      username = code.Converter_string(SqlLoginName).ToString();
      code.Execute(@"INSERT INTO User_Activity_Log VALUES('" + Convert.ToString(bunifuMaterialTextbox1.Text) + "','" + UserID + "','" + DateTime.Now + "','" + Login + "','" + CIP + "')");

      menu fr = new menu();
      this.Hide();
      fr.Show();
}       

在我的转换器字符串中找到我的代码

 public string Converter_string(string SQL)
    {
        try
        {
            SqlConnection con = Main.getConnection();
            DataTable consultanttable = new DataTable();
            string StringConsultant;
            SqlDataAdapter Consultantdataadapter = new SqlDataAdapter(SQL, con);
            Consultantdataadapter.Fill(consultanttable);
            foreach(DataRow myrow in consultanttable.Rows)
            {
                StringConsultant = Convert.ToString(myrow[0]);
                return StringConsultant;

            }
        }
        catch
        {
            System.Windows.MessageBox.Show("Successfully Login");
        }
        return "0";
    }