Create a Visual Basic. NET Control from scratch (iii)

visual| Create | Control Step 2nd: Change the base class
Classes created in the control library are automatically named UserControl1 and, by default, inherit from the UserControl class. If we want to create a composite control, it's very easy to just drag the other controls from the Toolbox onto the design surface.

However, since we are creating our own controls from scratch, we need to make some changes. Change the name of the control class from UserControl1 to TrafficLight. Then, the following line will be used:

Inherits System.Windows.Forms.UserControl

Change to:

Inherits System.Windows.Forms.Control

In this way, the most common control class becomes the base class. Instead of displaying the visual design surface, you will find that it is replaced with the component design surface.

To keep the code consistent, change the code file name from UserControl1.vb to Trafficlight.vb. You can make changes in Solution Explorer (Solution Explorer) by right-clicking the name of the code file and choosing Rename (rename).

You also need to add a few lines of code at the top of the class module. Set Option Strict to on and import the namespaces that contain some of the properties that we will use in the future. Here are two lines to put to the top of the code:

Option Strict on
Imports System.ComponentModel