SetFocus issue

[Bernard 20]

Hello All,

 

I have had an annoying issue in Delphi 10.3.2 setting focus back to a TFileListBox component after loading a file into an ActiveX control.

 

Here is the code for the Click on the FileListBox

 

  procedure TfrmCAD.flbCadClick(Sender: TObject);
  begin
    LoadFile;
    flbCAD.SetFocus;
  end;

 

On execution I would expect the focus to return to the flbCAD TFileListBox control.

This does not happen.

 

If I do the following code it does...

 

procedure TfrmCAD.flbCadClick(Sender: TObject);
begin
  LoadFile;
  btnDetect.SetFocus;
  flbCAD.SetFocus;
end;

 

Is this a bug in the VCL or am I doing something wrong?

 

Thanks

 

 

 

[Uwe Raabe 2064]

Doesn't the control already has the focus during the OnClick event? In that case a WM_SETFOCUS message might not be sent.

[David Heffernan 2353]

What happens if you don't call LoadFile? 

[Lars Fosdal 1793]

Is it just me, or does it seem to be slightly different behavior for Focus and BringToFront in Windows 10 1809 and later?

I've had several experiences with Application modal windows popping up behind the main window, and it has not only been my own Delphi apps.

Starting a Delphi App in the IDE for debugging, would leave the app running behind the BDS now and then.

I've had MSSQL Server Management Studio 17.x become unusable with a popup locked behind its main window when left running overnight, on several occasions. 

[David Heffernan 2353]

That's not an issue with focus. It's an issue with window owner, or popup parent in VCL terminology. 

[Bernard 20]

Hi Guys thanks for the swift replies and sorry for the delay in getting back to you all.

 

When I do not call the loadfile; Focus remains on the TFileListBox component as is expected;

 

When I do call the Loadfile on its own...

The loadfile loads a cadfile into an activeX component and at this point focus is lost. 

I have also noticed that, at the point focus is lost, the tab button no longer gives focus to any of the other controls on the form.

 

The activex control is a visual control EWDraw 3D.

 

Is there something I am missing in the activeX end.  Do I need to catch the tab key and send messages from its keyboard event?

[David Heffernan 2353]

Well, I guess it's clear now that the issue is not Delphi, but rather what your ActiveX control does. Perhaps it's worth asking the vendor. 

[aehimself 399]

...ooooor the focus actually stays on the button, it's just not redrawn properly. ActiveX controls work in strange ways (I still have active / not active issues with embedded MSTSC controls up to this day...)

You can verify this by comparing form..ActiveControl with your button.

[Guest]

2 hours ago, Bernard said:

Is there something I am missing in the activeX end.

Ahhh... the old ActiveX. Well. I think (and i might be mistaken) that these ActiveX-related thingies are legion and that the workaround are prominent in sources like TWebBrowser and the like. I avoid these things as much as i can, but i have a lot of murky memories of having to fiddle with interfaces (COM) and a sleuth of other trickery. Dig in to other projects using ActiveX, i guess you'll find comments and workarounds galore pertaining to your issue.

[PeterBelow 239]

19 hours ago, Bernard said:

Hi Guys thanks for the swift replies and sorry for the delay in getting back to you all.

 

When I do not call the loadfile; Focus remains on the TFileListBox component as is expected;

 

When I do call the Loadfile on its own...

The loadfile loads a cadfile into an activeX component and at this point focus is lost. 

I have also noticed that, at the point focus is lost, the tab button no longer gives focus to any of the other controls on the form.

 

The activex control is a visual control EWDraw 3D.

 

Is there something I am missing in the activeX end.  Do I need to catch the tab key and send messages from its keyboard event?

That sounds as if the form is no longer the foreground window after the ActiveX control hasloaded the file.  Try to add a

BringToFront;

after the LoadFile line.

[Bernard 20]

Tried BringToFront after the LoadFile Command and I am still getting the same issue. 

I accept there is a good chance this is a vendor issue. 

I am going to stick with my workaround at the minute...

 

procedure TfrmCAD.flbCadClick(Sender: TObject);
begin
  LoadFile;
  btnDetect.SetFocus;
  flbCAD.SetFocus;
end;

 

and send a bug report to the vendor.  I appreciate all the help guys.