Private Sub ComboBoxName_KeyPress(ByVal sender As System.Object, ByVal e As KeyPressEventArgs) Handles ComboBoxName.KeyPress
        If Not Equals(e.KeyChar, ControlChars.Back) Then
            Dim strLength As Integer = ComboBoxName.Text.Length
            Dim counter As Integer = ComboBoxName.FindString(ComboBoxName.Text)
            If counter <> - 1  Then
                ComboBoxName.Text = ComboBoxName.GetItemText(ComboBoxName.Items.Item(counter))
                ComboBoxName.Select(strLength, ComboBoxName.Text.Length)
            End If
        End If
     End Sub

    Dim q As String

    Private Sub ComboBox1_KeyPress(ByVal sender As Object, ByVal e As KeyPressEventArgs) Handles ComboBox1.KeyPress
       Dim counter As Integer = ComboBox1.FindString(q & e.KeyChar)
       If counter <> - 1  Then
           ComboBox1.Text = ComboBox1.GetItemText(ComboBox1.Items.Item(counter))
           q &= e.KeyChar
       Else
           q = e.KeyChar
       End If
   End Sub

        Dim counter As Integer = ComboBox1.FindString(q & e.KeyChar)
        If counter <> - 1  Then
            ComboBox1.Text = ComboBox1.GetItemText(ComboBox1.Items.Item(counter))
            q &= e.KeyChar
        Else
            q = e.KeyChar
            ComboBox1.Text = ComboBox1.GetItemText(q)
        End If

Public Class cboAutoComplite
    Inherits ComboBox
    Private q As String

    Protected Overrides Sub OnKeyPress(ByVal e As KeyPressEventArgs)
        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
    End Sub
End Class