After I extend a textbox in my own class and inherit like so

Code:
Inherits System.Web.UI.WebControls.TextBox
Then I can register it to my aspx page like so

Code:
<%@ Register TagPrefix="mtb" Namespace="MyTextBoxNamespace" %>
But now HOW do I simulate the same behavior as the TextMode property where I present a dropdown list of options and perform an action based upon what the user selects at design time? I played with an arraylist but I do not like that behavior.

Here is the Class

Code:
Imports Microsoft.VisualBasic

Namespace MyTextBoxNamespace
    Public Class MyTextBox
        Inherits System.Web.UI.WebControls.TextBox

        Private _BindableObject As ArrayList
        Public ReadOnly Property BindableObject() As ArrayList
            Get
                _BindableObject = New ArrayList
                _BindableObject.Add("test4")
                _BindableObject.Add("test5")
                Return _BindableObject
            End Get
            'Set(ByVal value As ArrayList)
            '    _BindableObject = value
            'End Set
        End Property
    End Class
End Namespace