Msgbox in a Callback.

[Olav Bergesen]

Should this be avoided?

Hi,
In my program, in a %CBN_CLOSEUP message, I have placed two calls in row to the same function(different parameters) and one call to a second function. The functions reads data from two files.

Values collected from the files is then displayed in some controls, among them 3 listview controls. The controls is located on a one paged Tabcontrol with its own callback, and it all works fine until a Msgbox call is placed before call to the functions. Then no controls is updated with the new data values.

Anyone any clue?

[Borje Hagsten]

Question is - why CBN_CLOSEUP? MS speaks, "In general, you cannot predict the order in which notifications will be sent. In particular, a CBN_SELCHANGE notification message may occur either before or after a CBN_CLOSEUP notification message."

So maybe when focus shifts to MSGBOX, it intercepts selection / closeup notifycations. If MSGBOX is necessary, maybe can try acting on CBN_SELCHANGE instead and see if that helps.

[Rodney Hicks]

You may be experiencing a re-entry problem with MSGBOX, code not shown, LOCAL variables may be being reset on re-entry. Borje's suggestion should work, if that's the case.

[Olav Bergesen]

To Borje:
Sorry, didn't work, but I got it to work now. To share an issue with someone always inspires to try harder.

In addition to what explained I also had code to save existing values in the controls under %CBN_Setfocus, and as said before, loaded new values under %cbn_closeup. Saving for one weekday and load for a different one.

The weekday variable is a static one and caused the problem.

Now I have placed a control get text... in the %CBN_DropDown to fetch current weekday showing in the combobox(saving) and the same call before fetching the new values.

Both saving and fetching data is now placed under the %CBN_SelEndOk message.

Very odd that there was no problem without the Msgbox.

Thanks for support.
--

[Michael Mattias]

You may be experiencing a re-entry problem with MSGBOX, code not shown, LOCAL variables may be being reset on re-entry

Ditto.

If you want to add some "display information for debugging purposes" without re-entrancy issues like this you might just want to add a STDOUT function as shown in this demo:

Simple STDOUT for PB/DLL and PB/Win 2-13-04