[[Property:title|Tutorial Step 2]]
[[Property:weight|1]]
[[Property:uuid|f4a73538-8a2f-ce6b-5190-6bd4d0e8c8d1]]
This sample shows you how to respond to an event occurring within your application. It also demonstrates the use of a [[ref:libraries/wel/reference/wel_msg_box_chart|WEL_MSG_BOX]]  control and a redefinition of closeable from [[ref:libraries/wel/reference/wel_composite_window_chart|WEL_COMPOSITE_WINDOW]] .

[[Image:step2|step2]]  <br/>
<br/>

==Compiling==

* Launch EiffelStudio. 
* Click '''Add project'''
* Browse to ''$ISE_EIFFEL\examples\wel\tutorial\step2\''. 
* Choose ''tutorial_step2.ecf''
* Choose the location where the project will be compiled, by default the same directory containing the configuration file. 
* Click '''OK'''. 


==Running==

After launching the sample, you should see a [[ref:libraries/wel/reference/wel_frame_window_chart|WEL_FRAME_WINDOW]]  displayed. If you click the left mouse button in the client area of the window, a [[ref:libraries/wel/reference/wel_msg_box_chart|WEL_MSG_BOX]]  will appear, notifying you of your click.

==Under the Hood==

This system is a demonstration of how to connect an event to one of the common message hooks available within WEL. See [[WEL Common Concepts|Common message hooks]] for more information. In this example, <code>on_left_button_down</code> has been redefined from [[ref:libraries/wel/reference/wel_window_chart|WEL_WINDOW]]  to display a [[ref:libraries/wel/reference/wel_msg_box_chart|WEL_MSG_BOX]]  containing notification of the event occurring. 

If you look at <code>closeable</code> from <code>MAIN_WINDOW</code>, you will see that it has been redefined to display a [[ref:libraries/wel/reference/wel_msg_box_chart|WEL_MSG_BOX]]  and the result from this message box is used to generate the return value of <code>closeable</code>. If this <code>Result</code> is <code>True</code>, the window will be closed. 
This sample contains the following classes: 
* <code>TUTORIAL_STEP2</code>
* <code>MAIN_WINDOW</code>


{{seealso|<br/>
[[WEL Common Concepts|Common message hooks]]  <br/>
}}