[.NET] 請問以DataReader的DataTable可以修改值嗎

[iconograph (return false;)]

VB.NET的問題
各位前輩你們好,目前剛接觸vb.net關於資料流的部份有些疑問
請前輩們不吝指教,謝謝

問題敘述:
以sqlDataReader形式得到了DataTable("OnLine_mtr"),
之後把這個table丟入畫面中的DataGridView1中,接著我在DataGridView1中處理我的資料,
比方A<B,那麼backColor為黃底,
而AX002這個欄位值原本20100217001,我要改成31A-20100217001-0001卻會得到一個錯誤訊息
訊息為:

"在DataGridView中發生下列例外狀況:
System.ArgumentException:無法設定資料行'AX002'該值違反了這個資料行的
MaxLength限制"

問一:是否在sqlDataReader無法這樣修改值?因為長度已經固定了?
     即使增加長度也不行DataGridView1.Columns(0).Width = 150

問二:有什麼解決的方式?

      請前輩們指點,大大感謝~!


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click

        Dim thisConnection As New SqlConnection("Data
Source=127.0.0.1;Initial Catalog=abc;User ID=sa;Password=123123")



        Dim TD001, TD002, TD003, sql As String

        sql = "SELECT * from A_TABLE"

        Dim thisCommand As New SqlCommand(sql, thisConnection)

        Dim thisReader As SqlDataReader

        Try

            thisConnection.Open()

            thisReader = thisCommand.ExecuteReader()

            Dim dt As New DataTable("OnLine_mtr")

            dt.Load(thisReader)

            DataGridView1.DataSource = dt



            'Assign New Width to DataGrid column

            'DataGridView1.Columns(0).Width = 150


            For i = 0 To dt.Rows.Count - 1

                Form_num001 = dt.Rows(i).Item("AX001").ToString()

                Form_num002 = dt.Rows(i).Item("AX002").ToString()

                Form_num003 = dt.Rows(i).Item("AX003").ToString()


                DataGridView1.Rows(i).Cells(0).Value = "無錫自購"

                If TD001 = "" Then

                    DataGridView1.Rows(i).Cells(1).Value = Trim(Form_num 001)
& "-" & Trim(Form_num 002)

                Else

                    DataGridView1.Rows(i).Cells(1).Value = Trim(Form_num 001)
& "-" & Trim(Form_num 002) & "-" & Trim(Form_num 003)  '--錯誤發生--

                End If

            Next



            thisReader.Close()

        Catch ex As Exception

            MessageBox.Show(ex.Message)

        Finally

            thisConnection.Close()

        End Try

End sub







  Private Sub customerDataGridView_CellFormatting(ByVal sender As Object,
ByVal e As DataGridViewCellFormattingEventArgs) Handles
DataGridView1.CellFormatting

        DataGridView1.Columns(0).HeaderText = " mtr_kind"

        DataGridView1.Columns(1).HeaderText = " form_num"

        DataGridView1.Columns(2).HeaderText = " send_date"

        DataGridView1.Columns(3).HeaderText = " vendor_name"

        DataGridView1.Columns(4).HeaderText = " mtr_no"

        DataGridView1.Columns(5).HeaderText = " desc"

        DataGridView1.Columns(6).HeaderText = " amount"

        DataGridView1.Columns(7).HeaderText = " arrive_date"

        DataGridView1.Columns(8).HeaderText = " rec_amt"

        DataGridView1.Columns(9).HeaderText = "memo_A"

        DataGridView1.Columns(10).HeaderText = “memo_B"

       '過期則黃底

     For i = 0 To DataGridView1.Rows.Count - 1

            If DataGridView1.Rows(i).Cells(3).Value <
String.Format("{0:yyyymmdd}", DateTime.Now) Then

                DataGridView1.Rows(i).DefaultCellStyle.BackColor =
Color.Yellow

            End If

        Next

    End Sub


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→ hjt00:你要不要考慮在Datatable做，然後噴給GridView顯示??
→ iconograph:不好意思,請問DataTable要怎麼去處理欄位A&"-"&B
推 horngsh:用"噴"這個字, 真有意思。
推 horngsh:據我所知, DataReader進來的記錄是唯讀的...
推 cawQQ:推樓上的...直接在DS當中作處理也是可以