TCPmaker : Visual Tour    Sending Messages to Screen Controls  

If you think about it, every Windows program you have ever run has changed its appearance in subtle ways from one moment to the next, usually to guide your actions.

  Here are some examples:

  • Controls like buttons or text boxes will sometimes appear greyed out (disabled) in order to show you that it is not meaningful for you to click them right now.  Even if you do click on them when they are in the disabled state, nothing will happen.
  • Similarly, sometimes menu items will appear or disappear at times, to restrict your choices and prevent you from choosing something that would cause harm.
  • Some Windows programs will change the color of some screen controls or text, to indicate a good or bad situation.

The ability to change the appearance of controls on the screen is useful technique that Windows software developers use a lot. 

As a TCPmaker Pro developer, you can do those sorts of things as well.  You can easily add a few lines to the code in your embedded web device to tell the TCPmaker controls on your browser screen to change their text, color, transparency, rotation, and so on.

This tutorial shows you how to do things like that, and suggests some reasons why you might want to do so in your application at times.  We'll build up a sample application (included in your TCPmaker Pro installation) to demonstrate these capabilities.


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