[2008] DataGridView Question - Inserting New records to database conditionally

On the main form of my app, I have a binding navigator that will navigate between records stored in the main table of the database. There is also a button on the form that can be clicked that inserts some data into a new table dependent on the ksID that is active on the form. Here is the code I have for that button now.

Is this the right idea? Also, if this button is clicked a 2nd time after a record is saved, I don't want it to insert a new record since one already exists. How would this be accomplished?

Code:

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

connetionString = "Data Source=HERCULES;Initial Catalog=Carc2;Integrated Security=True"
        sql = "SELECT * FROM t_resales"
        connection = New SqlConnection(connetionString)
        Try
            connection.Open()
            command = New SqlCommand(sql, connection)
            adapter.SelectCommand = command
            adapter.Fill(ds1, "Add New")
            adapter.Dispose()
            command.Dispose()
            connection.Close()

            dv = New DataView(ds1.Tables(0))
            Dim newRow As DataRowView = dv.AddNew()
            newRow("ksId") = txtKsId.Text
            newRow("Quantity") = txtResales.Text
            newRow("Weight") = txtResalesWeight.Text
            newRow("PaidAmount") = txtResalePay.Text
            'newRow("Reason") = "test"
            newRow.EndEdit()
            'dv.Sort = "product_id"

            frmResales.dgvResales.DataSource = dv

        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try
        frmResales.ShowDialog()



    End Sub

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still having this issue. Any ideas?

can just a simple If statement resolve this? I have tried it to no avail.