void clear()
 {
     GridUniqeGstin.DataSource = null;
     GridUniqeGstin.DataBind();
     GridGroupFilter.DataSource = null;
     GridGroupFilter.DataBind();
     grdGSTR2AData.DataSource = null;
     grdGSTR2AData.DataBind();
     ViewState["AllData"] = null;
     PnlAlldata.Visible   = false;
 }
 protected void GridGroupFilter_RowCommand(object sender, GridViewCommandEventArgs e)
 {
     if (e.CommandName == "GSTINDetail")
     {
         pnlUniqe.Visible = true;
         string    gstin       = e.CommandArgument.ToString();
         DataTable tblFiltered = new DataTable();
         DataTable dtall       = new DataTable();
         dtall       = (DataTable)ViewState["AllData"];
         tblFiltered = dtall.AsEnumerable().Where(r => r.Field <string>("PurchGSTIN") == gstin)
                       .CopyToDataTable();            // Filter(unique) group  Zone wise
         GridUniqeGstin.DataSource = tblFiltered;
         GridUniqeGstin.DataBind();
     }
 }