Events That Trigger a Foundation READ in FoxPro

• Microsoft FoxPro for MS-DOS, versions 2.0, 2.5, and 2.5a
• Microsoft FoxPro for Windows, versions 2.5 and 2.5a

SUMMARY

Microsoft FoxPro supports a READ command that does not contain any GET clauses. It is termed a "foundation READ." A foundation READ is the controlling READ command that has a VALID clause. The VALID clause controls nested, or child, READ commands. The VALID clause in a foundation READ is triggered by events that would terminate the READ command, such as the following:

• CLEAR READ. In a READ command with a GET clause, the VALID clause is not called for a CLEAR READ command.
• A key press or mouse click that does not correspond to a menu selection or is not listed in an ON KEY LABEL command.

MORE INFORMATION

A CLEAR READ invokes the READ VALID clause only on a foundation READ. For example, consider an application that starts a foundation READ as indicated below:

   DO MAIN.MPR
   READ VALID handler()    &&  Wait for the user to take action.

During a normal READ command (with a GET clause), the following events trigger the VALID clause: pressing CTRL+W, pressing ESC, pressing the TAB key past the last GET when READ CYCLE is off, or pressing TAB past the first GET when READ CYCLE is off. Note that issuing a CLEAR READ command does not trigger the VALID clause.

During a foundation READ (without a GET clause), the following events trigger the VALID clause: pressing CTRL+W, pressing ESC, clicking the mouse, and any key press that does not correspond to a menu selection or to an ON KEY LABEL command.