PRB: CLEAR EVENTS in Modal Form Does Not Clear a READ (130387)

SYMPTOMS

A modal form is run from a program with a DO FORM command followed by a READ EVENTS. A command button on the form has the following method in its Click event:

   RELEASE THISFORM
   CLEAR EVENTS

When the button is clicked, the form is released but the READ EVENTS is not cleared.

CAUSE

When a modal form is displayed, execution of a program is suspended. Modal forms do not require a READ EVENTS. In the case described in this article, the READ EVENTS command has not yet been executed when the CLEAR EVENTS is issued. Program execution is suspended.

RESOLUTION

Do not use the READ EVENTS command if you have a modal form or form set. To verify the modality of your form, check the value of the WindowType property. When a form is modal, the WindowType property is equal to 1. For more information about displaying modal forms or form sets, search for the WINDOWTYPE property or the SHOW method in the Visual FoxPro Help menu.

MORE INFORMATION

Steps to Reproduce Behavior

The following sample code displays a modal form. When the form is displayed and the command button is clicked, the form is released, but control does not return to the Command window. To correct this sample, remove the READ EVENTS and CLEAR EVENTS commands from the code.

   omyform=CREATEOBJECT('myform')
   omyform.Show(1)       && Displays a modal form
   READ EVENTS

   DEFINE CLASS myform AS form
     WindowType=0
     ADD OBJECT mycmd AS CommandButton
     PROCEDURE mycmd.Click
       RELEASE Thisform
       CLEAR EVENTS
     ENDPROC
   ENDDEFINE