[C#]gridview控制項值pageload時重新傳給DB

//fgvIFGAA10FD1不在編輯區製作的資料要重新load
     
ftbMTDT.Text = DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss");
ftbMTPGMID.Text = "IFGAA30F";
ftbMTUSERID.Text = this.Master.User.USERID;
               
for (int i = 0; i < fgvD80.Rows.Count; i++)
                {
                    DataTable dt = new DataTable() ;
                    dt = fgvD80.TempTable;//這裡被唯讀要解決
                    foreach (DataColumn dc in dt.Columns)
                    {
                        dc.ReadOnly = false;
                  }
TextBox tbVENDORNUM2 = (TextBox)fgvD80.Rows[i].FindControl("tbVENDORNUM2");
TextBox tbVENDORPAYMODE =(TextBox)fgvD80.Rows[i].FindControl("tbVENDORPAYMODE");
TextBox tbVENDORPAYDATE = (TextBox)fgvD80.Rows[i].FindControl("tbVENDORPAYDATE");
dt.Rows[i]["VENDORNUM2"] = tbVENDORNUM2.Text.Trim();
dt.Rows[i]["VENDORAMTS"] = Convert.ToInt32(tbVENDORNUM2.Text.Trim()) * Convert.ToInt32(dt.Rows[i]["VENDORAMT"].ToString());
dt.Rows[i]["VENDORPAYMODE"] = tbVENDORPAYMODE.Text.Trim();
dt.Rows[i]["VENDORPAYDATE"] = tbVENDORPAYDATE.Text.Trim();
                   
dt.Rows[i]["MTUSERID"] = this.Master.User.USERID;
dt.Rows[i]["MTPGMID"] = "IFGAA30F";
dt.Rows[i]["MTDT"] = DateTime.Now.ToString("yyyy/MM/dd HH:mm:ss");

//注意順序，先AcceptChanges再做DataBind
fgvD80.TempTable.AcceptChanges();
fgvD80.DataBind(fgvD80.TempTable);