Protected Overrides Sub OnKeyPress(ByVal e As KeyPressEventArgs)
        MyBase.DropDownStyle = ComboBoxStyle.DropDown
        MyBase.OnKeyPress(e)
        Dim counter As Integer = MyBase.FindString(q & e.KeyChar, - 1 )
        If counter <> - 1  Then
            MyBase.Text = MyBase.GetItemText(MyBase.Items.Item(counter))
            q &= e.KeyChar
        Else
            q = e.KeyChar
            counter = MyBase.FindString(q, - 1 )
            If counter = - 1  Then
                MyBase.Text = ""
            Else
                MyBase.Text = MyBase.GetItemText(MyBase.Items.Item(counter))
            End If
        End If
        MyBase.DropDownStyle = ComboBoxStyle.DropDownList
    End Sub

Public Class cboAutoComplite
    Inherits ComboBox
    Private q As String
    Private ddStyle As ComboBoxStyle

    Protected Overrides Sub OnKeyPress(ByVal e As KeyPressEventArgs)
        ddStyle = MyBase.DropDownStyle
        MyBase.DropDownStyle = ComboBoxStyle.DropDown
        MyBase.OnKeyPress(e)
        Dim counter As Integer = MyBase.FindString(q & e.KeyChar, - 1 )
        If counter <> - 1  Then
            MyBase.Text = MyBase.GetItemText(MyBase.Items.Item(counter))
            q &= e.KeyChar
        Else
            q = e.KeyChar
            counter = MyBase.FindString(q, - 1 )
            If counter = - 1  Then
                MyBase.Text = ""
            Else
                MyBase.Text = MyBase.GetItemText(MyBase.Items.Item(counter))
            End If
        End If
        MyBase.DropDownStyle = ddStyle
    End Sub
End Class