asp.net - gridviewループの問題

Question

4列のグリッドビューがあります。そのうちの3つは、ユーザーが必要な情報を入力し、ボタンをクリックしてデータベースに送信できるテンプレートフィールドです。私には2つの問題があります：

1. ボタンをクリックして2行目を追加すると、最初の行の投稿のデータが
   消えます。複数のレコードエントリの状況で、情報の最初の行が消えることなく行を追加できるようにしたい。私のコードは次のとおりです。

   Private Sub SetInitialRow()
       Dim dts As New DataTable()
       Dim drs As DataRow = Nothing
       dts.Columns.Add(New DataColumn("Approval Date", GetType(String)))
       dts.Columns.Add(New DataColumn("Total Amount", GetType(String)))
       dts.Columns.Add(New DataColumn("Comments", GetType(String)))
       dts.Columns.Add(New DataColumn("Initials", GetType(String)))
       drs = dts.NewRow()
       drs("Approval Date") = String.Empty
       drs("Total Amount") = String.Empty
       drs("Comments") = String.Empty
       drs("Initials") = String.Empty
       dts.Rows.Add(drs)
       ViewState("CurrentTable") = dts
       gvOLIAdj.DataSource = dts
       gvOLIAdj.DataBind()
   End Sub
   
   Private Sub AddNewRowToGrid()
       Dim rowIndex As Integer = 0
       If ViewState("CurrentTable") IsNot Nothing Then
           Dim dtCurrentTable As DataTable = DirectCast(ViewState("CurrentTable"), DataTable)
           Dim drCurrentRow As DataRow = Nothing
           If dtCurrentTable.Rows.Count > 0 Then
               For i As Integer = 1 To dtCurrentTable.Rows.Count
                   'extract the TextBox values
                   Dim box1 As TextBox = DirectCast(gvOLIAdj.Rows(rowIndex).Cells(1).FindControl("txtAdjAppr"), TextBox)
                   Dim box2 As TextBox = DirectCast(gvOLIAdj.Rows(rowIndex).Cells(2).FindControl("txtAdjAmt"), TextBox)
                   Dim box3 As TextBox = DirectCast(gvOLIAdj.Rows(rowIndex).Cells(3).FindControl("txtCmmts"), TextBox)
                   drCurrentRow = dtCurrentTable.NewRow()
                   drCurrentRow("Approval Date") = box1.Text
                   dtCurrentTable.Rows(i - 1)("Total Amount") = box2.Text
                   dtCurrentTable.Rows(i - 1)("Comments") = box3.Text
                   'dtCurrentTable.Rows(i - 1)("Initials") = 
                   rowIndex += 1
               Next
               dtCurrentTable.Rows.Add(drCurrentRow)
               ViewState("CurrentTable") = dtCurrentTable
               gvOLIAdj.DataSource = dtCurrentTable
               gvOLIAdj.DataBind()
           End If
       Else
           Response.Write("ViewState is null")
       End If
       'Set Previous Data on Postbacks
       SetPreviousData()
   End Sub
   
   Private Sub SetPreviousData()
       Dim rowIndex As Integer = 0
       If ViewState("CurrentTable") IsNot Nothing Then
           Dim dats As DataTable = DirectCast(ViewState("CurrentTable"), DataTable)
           If dats.Rows.Count > 0 Then
               For i As Integer = 0 To dats.Rows.Count - 1
                   Dim box1 As TextBox = DirectCast(gvOLIAdj.Rows(rowIndex).Cells(1).FindControl("txtAdjAppr"), TextBox)
                   Dim box2 As TextBox = DirectCast(gvOLIAdj.Rows(rowIndex).Cells(2).FindControl("txtAdjAmt"), TextBox)
                   Dim box3 As TextBox = DirectCast(gvOLIAdj.Rows(rowIndex).Cells(3).FindControl("txtCmmts"), TextBox)
                   box1.Text = dats.Rows(i)("Approval Date").ToString()
                   box2.Text = dats.Rows(i)("Total Amount").ToString()
                   box3.Text = dats.Rows(i)("Comments").ToString()
                   rowIndex += 1
               Next
           End If
       End If
   End Sub
   
   Protected Sub btnAddNewRow_Click(sender As Object, e As EventArgs) Handles btnAddNewRow.Click
       AddNewRowToGrid()
   
   End Sub
   

2. 各テンプレートフィールドをループしてデータを取得してデータベースに配置するループを作成しようとすると、テンプレートフィールドにデータがあることを認識しませんか？これは私がこれまで何の役にも立たなかったことです...

   Protected Sub btn_Update_Click(sender As Object, e As EventArgs) Handles btn_Update.Click
       For Each row As GridViewRow In gvOLIAdj.Rows
           For Each gv As GridViewRow In gvOLIAdj.Rows
               Dim appDt As String = (Rows(rowIndex).Cells(1).FindControl("txtAdjAppr")), TextBox)
               Dim approvalDt As String = CType(gv.FindControl("txtAdjAppr"), TextBox).Text
               Dim totalAmt As String = CType(gv.FindControl("txtAdjAmt"), TextBox).Text
               Dim comments As String = CType(gv.FindControl("txtcmmts"), TextBox).Text
               Dim intitials As String = DirectCast(gv.FindControl("total"), TextBox).Text
       Next
   
   End Sub