PRB: Lockscreen with Assert Dialog Causes Problems with Controls
ID: Q168039
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The information in this article applies to:
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Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a
SYMPTOMS
When you run a form, clicking on a checkbox does not change its state. If
there are option buttons on the form, clicking the checkbox may change the
state of the option buttons. Clicking the checkbox may even select more
than one option button in the same option group. Clicking one of the option
buttons may change the state of the checkbox. In other words, the
checkboxes and option buttons are malfunctioning.
CAUSE
Several factors lead to this behavior. First, ASSERTS must be set ON and
the LockScreen property of the form changed to true (.T.) before an
expression that is ASSERTed evaluates to false (.F.). Next, Ignore or
Ignore All must be chosen in the message box displayed by the ASSERT
command. Finally, LockScreen must be changed back to false (.F.).
RESOLUTION
Do not use LockScreen when using the ASSERT command.
STATUS
Microsoft is researching this problem and will post new information here in
the Microsoft Knowledge Base as it becomes available.
MORE INFORMATION
When SET ASSERTS is ON, the ASSERT command will display a message box if a
logical expression evaluates to false (.F.).
The following commands issued from within a program file will illustrate:
SET ASSERTS ON
ASSERT 1=2 && will cause a message box.
Steps to Reproduce Behavior
- Place the following code in a program file and run the program:
SET ASSERTS ON
oForm1 = CREATEOBJECT("test")
oForm1.Visible = .t.
READ EVENTS
DEFINE CLASS test AS form
ADD OBJECT cmdNewForm AS ccmdNewForm
ADD OBJECT chkBox AS CheckBox WITH ;
left = 10, ;
top = 30
ADD OBJECT opgBox AS OptionGroup WITH ;
Width = 80, ;
Height = 50, ;
ButtonCount = 2, ;
option1.Caption = "Option1", ;
option1.Autosize = .T., ;
option2.Caption = "Option2", ;
option2.Autosize = .T., ;
left = 10, ;
top = 50
FUNCTION Destroy
CLEAR EVENTS
ENDFUNC
ENDDEFINE
DEFINE CLASS ccmdNewForm AS CommandButton
Caption = "Dialog"
FUNCTION Click
Thisform.LockScreen = .T.
ASSERT 1=2
Thisform.LockScreen = .F.
?Thisform.LockScreen
CLEAR
ENDFUNC
ENDDEFINE
- When the program is run, a form with a command button, a checkbox and an
option group is displayed. Click on the checkbox and option buttons to
verify that they work normally.
- Now click on the command button. This should bring up the message box
from the ASSERT command. It should have the message:
"Assertion failed on line 2 of procedure test1.cmdnewform.click"
Choose the Ignore button.
- Back on the form, click on the Chkbox and note that it does not become
checked. Then click on Option2 and note that Chkbox checks. Then click
on the Chkbox and note that both option buttons are selected.
REFERENCES
Visual FoxPro Online Help
Additional query words:
Keywords : kbVFp FxprgGeneral FxtoolFormdes
Version : 5.00 5.00a
Platform : WINDOWS
Issue type :