[سؤال] لماذا يقوم امر الحفظ بتكرار البيانات

كود :

Imports System.Data.OleDb



Public Class DataSetTest

    Dim Sqltr As String = " Select * From Tb"

    Dim ConString As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & "Data Source=|DataDirectory|\db2.mdb;"

    Dim Da As New OleDbDataAdapter(Sqltr, ConString)

    Dim Ds As New DataSet

    Dim Cmdb As New OleDbCommandBuilder



    Sub DataLoad()

        Da.Fill(Ds, "Tb")

        NameText.DataBindings.Add("Text", Ds, "Tb.Name")

        PhonNoText.DataBindings.Add("Text", Ds, "Tb.PhoneNo")

    End Sub



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

        DataLoad()

    End Sub



    Private Sub Save_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Save.Click

        Da.Update(Ds, "Tb")

    End Sub



    Private Sub NewRecord_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NewRecord.Click

        Me.BindingContext(Ds, "Tb").AddNew()

    End Sub



    Private Sub Add_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Add.Click



        Dim R As DataRow = Ds.Tables("Tb").NewRow



        R(0) = NameText.Text

        R(1) = PhonNoText.Text

        Ds.Tables("Tb").Rows.Add(R)

        Cmdb = New OleDbCommandBuilder(Da)

    End Sub

End Class

كود :

Private Sub NewRecord_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NewRecord.Click

   Me.BindingContext(Ds, "Tb").AddNew()

    End Sub

كود :

Private Sub Add_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Add.Click

     Dim R As DataRow = Ds.Tables("Tb").NewRow

        R(0) = NameText.Text

        R(1) = PhonNoText.Text

        Ds.Tables("Tb").Rows.Add(R)

        Cmdb = New OleDbCommandBuilder(Da)

    End Sub