Koding Simpan di VB .NET Access

Koding Simpan di  VB .NET Access

Private Sub Bsimpan_Click(sender As Object, e As EventArgs) Handles Bsimpan.Click
        If Tusername.Text = "" Or Tpassword.Text = "" Then
            MsgBox("Data Lengkapi dulu boss!")
            Exit Sub
            Else
                cmd = New OleDbCommand("select * from admin where username = '" & Tusername.Text & "'", conn)
                dr = cmd.ExecuteReader
                dr.Read()
                If Not dr.HasRows Then
                    Dim simpan As String = "insert into admin values ('" & Tusername.Text & "', '" & Tpassword.Text & "')"
                    cmd = New OleDbCommand(simpan, conn)
                    cmd.ExecuteNonQuery()
                Call tampil()
                Call kosong()
            Else
                MsgBox("Username sudah ADA!!!")
            End If
            End If
    End Sub