Hiii, I am trying to make dynamic interface for my application. I have lots of 2 field database table.i.e (ID,Name) For that doing each table each form i am trying to make it simple by making class file and passing query string parameter to li (Link of form) and then access it on page. accoridng to query string value i am making further operations. BUt value assign to variable on page load vanished on button click. I am also want to bind gridview on same way.

     //Method for Auto Increment(ID)

        public int Increment_ID(string _tblName, string FieldId)
        {
            int _MaxID = 0;
            try
            {
                using (OleDbConnection VMScon = new OleDbConnection(VMSConnectionString))
                {

                    OleDbCommand cmdVcReqId = new OleDbCommand("select nvl(max(" + FieldId + "),0) from " + _tblName + "", VMScon);
                    // 0 used to get value if there is no data found in table.
                    VMScon.Open();
                    _MaxID = Convert.ToInt16(cmdVcReqId.ExecuteScalar());
                    _MaxID = _MaxID + 1;
                    VMScon.Close();
                }

            }
            catch (Exception ex)
            {
                //AlertMsg.Attributes["class"] = "alert alert-danger";
                //lblmsg.Text = "Error Occured at Auto ID!!";
                //mpeMessageBox.Show();
            }
            return _MaxID;
        }

        
        public DataSet GetMasterData(string tablename, int Id)
        {
            //DataTable dt = new DataTable();
            DataSet ds = new DataSet();
            OleDbConnection conn = new OleDbConnection(VMSConnectionString);

            OleDbDataAdapter da = new OleDbDataAdapter();
            try
            {
                conn.Open();

                string cmdText = "SELECT * FROM " + tablename + " order by " + Id + " desc";
                OleDbCommand cmd = new OleDbCommand(cmdText, conn);
                cmd.Connection = conn;
                da.SelectCommand = cmd;
                da.Fill(ds);
            }

            catch (Exception e)
            {

                if (WriteExceptionsToEventLog)
                {
                    WriteToEventLog(e, "GetTasksForSelectedUser");

                }
                throw e;
            }
            finally
            {

                conn.Close();
            }

            return ds;
        }


        public int IsExistMasterData(string tablename,string FieldName,string description)
        {
            using (OleDbConnection VMScon = new OleDbConnection(VMSConnectionString))
            {
                int result = 0;
                try
                {
                    TextInfo objtxt = culterinfo.TextInfo;                  

                    _description = objtxt.ToUpper(description);

                    VMScon.Open();
                    OleDbCommand cmd = new OleDbCommand("Select * from "+tablename+" where "+FieldName+"=:description ", VMScon);
                    OleDbDataReader dr = cmd.ExecuteReader();
                    if (dr.Read())
                    {
                        result = 1;
                    }                    
                }
                catch (Exception ex)
                {
                    throw ex;

                }
                finally
                {
                    VMScon.Close();
                }
                return result;

            }

        }

        /// <summary>
        /// Add new New Current News in the PIS database
        /// </summary>
        /// <param name="News"></param>
        /// <returns>The number of Newss created</returns>
        public void AddMasterData(string tableName, string FieldId,string FieldName,string description)
        {
            using (OleDbConnection VMScon = new OleDbConnection(VMSConnectionString))
            {
                try
                {
                    TextInfo objtxt = culterinfo.TextInfo;

                    _maxId = Increment_ID(tableName, FieldId);

                    _description = objtxt.ToUpper(description);

                    string queryStr = "insert into " + tableName + " (" + FieldId + "," + FieldName + ")values(:ID,:Description)";
                    VMScon.Open();
                    OleDbCommand cmd = new OleDbCommand(queryStr, VMScon);
                    cmd.Parameters.Add(new OleDbParameter(":ID", _maxId));
                    cmd.Parameters.Add(new OleDbParameter(":Description", _description));
                    cmd.ExecuteNonQuery();

                    VMScon.Close();

                }
                catch (Exception ex)
                {
                    throw ex;

                }
                finally
                {
                    VMScon.Close();
                }
            }
        }

        public void UpdateMasterData(string tableName, string FieldId, string FieldName,int Id, string description)
        {
            using (OleDbConnection VMScon = new OleDbConnection(VMSConnectionString))
            {
                try
                {
                    TextInfo objtxt = culterinfo.TextInfo;

                    _description = objtxt.ToUpper(description);


                    string queryStr = "update " + tableName + " set " + FieldName + "=:description where " + FieldId + "=:ID";
                    VMScon.Open();
                    OleDbCommand cmd = new OleDbCommand(queryStr, VMScon);

                    cmd.Parameters.Add(new OleDbParameter(":description", _description));
                    cmd.Parameters.Add(new OleDbParameter(":FieldId", Id));

                    cmd.ExecuteNonQuery();
                    VMScon.Close();
                }

                catch (Exception ex)
                {
                    throw ex;

                }
                finally
                {
                    VMScon.Close();
                }

            }
        }



string tableName = "";
        string columnId = "";
        string columnName = "";
        string description = "";
        int result = 0;

        DbHelper db;
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                //string FormID = Request.QueryString["FormValue"].ToString();
                string FormID = "1";
                if (FormID != null)
                {
                    switch (FormID)
                    {
                        case "1":
                            tableName = "Mst_Country";
                            columnId = "Country_Id";
                            columnName = "Country_Name";
                            this.lblFieldName.Text = "Country Name";
                            break;
                        default:
                            break;
                    }
                }

            }
        }

        protected void btnSave_Click(object sender, EventArgs e)
        {
            result = db.AddMasterData(tableName, columnId, columnName, txtFieldName.Text);

            if (result > 0)
            {
                lblmsg.Text = "Record Saved Successfully !!!";
                mpeMessageBox.Show();
            }

        }