vb.net how to autocomplete textbox with a datatable

[axel48]

I've this code:

TextBox1.AutoCompleteMode = AutoCompleteMode.Append
        TextBox1.AutoCompleteSource = AutoCompleteSource.CustomSource
        If dttest.Rows.Count > 0 < 2 Then
            For counter As Integer = 0 To dttest.Rows.Count - 1
                TextBox1.AutoCompleteCustomSource.Add(dttest.Rows(counter)("test"))
            Next
            For counter As Integer = 0 To dttest.Rows.Count = 328
                If dttest.Rows(0).Item(0).ToString = TextBox1.Text Then
                    .....
                End If

But textbox doesn't get the autocomplete mode, in this way, it need only to check the rows of datatable, and if find correct match with one on textbox then append the left text.