ข้อมูลที่อยู่ใน DataGridview พอกดปุ่มเดิม ข้อมูลเดิมโชว์ซ้ำขึ้นมา ทำยังไงให้กดปุ่มเดิมแล้วข้อมูลไม่ขึ้นซ้ำคะ??

Imports System.Data
Imports System.Data.OleDb
Public Class Form2
    Dim conn As String
    Dim cn As New OleDbConnection
    Dim cm As New OleDbCommand
    Dim da As New OleDbDataAdapter
    Dim ds As New DataSet

    Dim cal As Integer
    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        conn = "provider=microsoft.jet.oledb.4.0; data source=c:\infoproductsDB.mdb"
        cn.ConnectionString = conn
        cm.Connection = cn
    End Sub
    Private Sub DataGridView_CellMouseUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) Handles DataGridView.CellMouseUp
        With DataGridView
            Try
                txtIDType.Text = .Rows.Item(e.RowIndex).Cells("IDType").Value.ToString()
                txtID.Text = .Rows.Item(e.RowIndex).Cells("ID").Value.ToString()
                txtName.Text = .Rows.Item(e.RowIndex).Cells("Name").Value.ToString()
                txtPriceUnit.Text = .Rows.Item(e.RowIndex).Cells("PriceUnit").Value.ToString()
            Catch ex As Exception
            End Try
        End With
    End Sub
    Public Sub SelectProductType()
        DataGridView.Columns.Item(0).HeaderText() = "รหัสสินค้า"
        DataGridView.Columns.Item(1).HeaderText() = "รหัสประเภทสินค้า"
        DataGridView.Columns.Item(2).HeaderText() = "ชื่อสินค้า"
        DataGridView.Columns.Item(3).HeaderText() = "ราคาต่อหน่วย"
    End Sub
    Private Sub btNovel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btNovel.Click
        cm.CommandText = "SELECT * FROM ProductsNovel"
        da.SelectCommand = cm
        da.Fill(ds, "ProductsNovel")
        DataGridView.DataSource = ds.Tables("ProductsNovel")
        SelectProductType()
    End Sub
    Private Sub btSStory_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btSStory.Click
        cm.CommandText = "SELECT * FROM ProductsShortStory"
        da.SelectCommand = cm
        da.Fill(ds, "ProductsShortStory")
        SelectProductType()
        DataGridView.DataSource = ds.Tables("ProductsShortStory")
        SelectProductType()
    End Sub
    Private Sub btCom_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btCom.Click
        cm.CommandText = "SELECT * FROM ProductsCom"
        da.SelectCommand = cm
        da.Fill(ds, "ProductsCom")
        SelectProductType()
        DataGridView.DataSource = ds.Tables("ProductsCom")
        SelectProductType()
    End Sub
    Private Sub btCal_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btCal.Click
        cal = txtPriceUnit.Text * txtPiece.Text
        txtAmount.Text = cal
    End Sub
    Private Sub btClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btClear.Click
        ds.Clear()
    End Sub
End Class