ช่วยหน่อยนะคะ เกี่ยวกับการ Merge DataTable ค่ะ คือเขียน คอนเน็คกับเซอฟเวอร์ จำนวน 8 เซอฟเวอร์ด้าน

public static ListItem[] GetSite()
        {           

            ListItem[] item = { new ListItem("AIT"), new ListItem("SAB"), new ListItem("AIC"), new ListItem("AIG"), new ListItem("JCK"),new ListItem( "SPK"), new ListItem("JCB"), new ListItem("CTS") };

            return item;

        }
    public static ClsServerSite GetServer(string RC, string Path)
        {
            ClsXML_Serialization xml = new ClsXML_Serialization();
            List<ClsServerSite> List = xml.DeserializeFromXml<List<ClsServerSite>>(Path);
           
            for (int i = 0; i <= List.Count - 1; i++)
            {
                if (List[i].RC_ == RC)
                {
                    return List[i];
                }
            }
            return null;
        
        }

 protected void btnsearch_Click(object sender, EventArgs e)
    {
//ตรวจสอบว่า user ได้เลือกที่จะแสดงข้อมูลของทุก Server หรือไม่
        if (txtSearch.Text.Trim() != "")
        {
           
            if (ddlRC.Text == "ALL") 
            {
                Session["servsite"] = "ALL";
                StrQ();
                ShowGridDataAll(); 
            }
            else
            {
                Session["servsite"] = ddlRC.Text;
                StrQ();
                ShowGridData(ddlRC.Text);
                
            }
        }
        else
        {
            ScriptManager.RegisterStartupScript(this, typeof(string), "Message", "alert('กรุณาระบุเงื่อนใขการค้นหา');", true);
            
        }

    }

 private void StrQ()
    {
        string STR = "";

        STR = " Select * ";
        STR += " From box_table ";
        STR += " Where " + ddlSearch.Text + " like '%" + txtSearch.Text.Trim() + "%' ";
        if (txtStartDate.Text.Trim() != "" && txtEndDate.Text.Trim() != "")
        {

            string startDate = txtStartDate.Text.Trim();
            string endDate = txtEndDate.Text.Trim();

            STR += " and commentdate >='" + startDate + " 00:00:00' ";
            STR += " and commentdate <='" + endDate + " 23:59:00' ";

        }
        if (ddlstatus.Text != "ALL")
        {
            STR += " and commentstatus='" + ddlstatus.Text + "'";
        }
        if (txtgroupno.Text.Trim() != "")
        {
            STR += " and CoverGroup='" + txtgroupno.Text.Trim() + "'";
        }
        STR += " and comment_doc<>'' ";
        STR += " Order by covergroup,coverlistno ;";

        

      
Session["strq"] = STR;
       
               
        


    }

 private void ShowGridDataAll()
    {

        //DataTable Main_DT = new DataTable();

            ListItem[] item = GetSite();

            for (int i = 0; i <= item.Length - 1; i++)
            {
                string rc = item[i].Value;
                ClsServerSite RC = GetServer(rc, Server.MapPath("Config/ConfigSubSite.xml"));
                ShowGridData(rc);



                    Main_DT.Merge(DT);
                   
               
            }

            if (Main_DT.Rows.Count == 0)
            {

                ScriptManager.RegisterStartupScript(this, typeof(string), "Message", "alert('No data search');", true);

                return;
            }
            GridData.DataSource = Main_DT;
            GridData.DataBind();
          
        
    }

  private void ShowGridData(string strRC)
    {
      
            DT.Clear();
            ClsServerSite RC = GetServer(strRC, Server.MapPath("Config/ConfigSubSite.xml"));
            using (ClsDB_SQL SQL = new ClsDB_SQL())
            {
                
                if (SQL.ConnectSubSite(RC))
                {

                    DT = SQL.Query_Select(Session["strq"] as string );

                    for (int i = 0; i <= DT.Rows.Count - 1; i++)
                    {
                        string sStatus = Convert.ToString(DT.Rows[i]["commentstatus"]);

                        if (sStatus == "Complete")
                        {
                            scomplete = scomplete + 1;
                        }
                        else if (sStatus == "Inprocess")
                        {
                            sinprocess = sinprocess + 1;
                        }
                        else
                        {
                            spending = spending + 1;
                        }
                    }
                    string chksite = Session["servsite"] as string;
                    if (chksite != "ALL")
                    {
                        if (DT.Rows.Count == 0)
                        {

                            ScriptManager.RegisterStartupScript(this, typeof(string), "Message", "alert('No data search');", true);

                            return;
                        }
                        GridData.DataSource = DT;
                        GridData.DataBind();
                        
                    }


                   
                    
                }
                else
                {
                    ScriptManager.RegisterStartupScript(this, typeof(string), "Message", "alert('Connecting Server Fail');", true);

                    return;

                   

                }
            }

    }