[مشروع] مثال اعادة الترقيم لعمود في الجدول

كود :
Public Class Form1

    Dim str As String = "provider=microsoft.ace.oledb.12.0;data source=|DataDirectory|\db.accdb"

    Dim con As New OleDb.OleDbConnection(str)

    Dim dt As DataTable

    Dim da As OleDb.OleDbDataAdapter

    Dim cmd As OleDb.OleDbCommandBuilder



    Private Function gid() As Integer

        Try

            Dim cm As New OleDb.OleDbCommand("select Last(tid) from tb", con)

            If con.State = ConnectionState.Closed Then con.Open()

            Return cm.ExecuteScalar

        Catch ex As Exception

            Return Nothing

        End Try

    End Function



    Private Sub gd()

        ListBox1.DataSource = Nothing

        dt = New DataTable

        da = New OleDb.OleDbDataAdapter("select * from tb", con)

        cmd = New OleDb.OleDbCommandBuilder(da)

        da.Fill(dt)

        ListBox1.DataSource = dt

        ListBox1.DisplayMember = "tid"

    End Sub

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

        gd()

    End Sub



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

        Dim row As DataRow = dt.NewRow

        row(0) = gid() + 1

        dt.Rows.Add(row)

        da.Update(dt)

        gd()

        ListBox1.SelectedIndex = ListBox1.Items.Count - 1

    End Sub



    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click

        If ListBox1.SelectedIndex < 0 Then MsgBox("اختر الرقم المراد حذفه من القائمة", MsgBoxStyle.Critical, "") : Return



        dt.Rows(ListBox1.SelectedIndex).Delete()

        da.Update(dt)

        gd()

    End Sub



    Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click

        ListBox1.DataSource = Nothing



        For r As Integer = 0 To dt.Rows.Count - 1

            Dim row As DataRow = dt.Rows(r)

            row.BeginEdit()

            row(0) = r

            row.EndEdit()

            da.Update(dt)

        Next

        gd()

    End Sub

End Class