TFileListBox "right click" behavior
lazarus / 31-LCL

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moit · 2010-06-25 10:00

So far I've tried this on Linux, OS X, and WinXP and see the same
behavior on all three.

I've got a TFileListBox that lists a bunch of files. I also have a
context menu that pops up when you right click on the TFileFileBox. It
works.

But ... the behavior I am seeing is that a "right click" does not also
select the item over which it has clicked. In other words, when I
right click over something, the selected item does not change. I note
that the "no-change on right-click" happens whether or not the
TFileFileBox is associated with a TPopupMenu or not.

What I would like to have happen is for a right click to also select
the item over which it has been clicked -- and then pop up the context
menu. Is there a magical incantation that will make this happen?

-M

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theo · 2010-06-26 00:10

Just try. I did and found that the following works.
Tested on Lazarus 0.9.29 r26057M FPC 2.4.0 i386-linux-gtk 2 (beta)

Code: [Select]procedure
TForm1.FileListBox1MouseDown(Sender:TObject;Button:TMouseButton;Shift:
  TShiftState;X,Y:Integer);
var item:integer;
begin
  item:=FileListBox1.ItemAtPos(Point(X,Y),true);
  if item>-1 then FileListBox1.Selected[item]:=true;
end;

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moit · 2010-06-26 02:42

Theo, your code on my 0.9.28.2-2 GTK gets closer. It selects the item
under the right-click. But for some reason the routines fired off by
the popup menu are seeing the 'old' selection. (For completeness, the
popup menu brings up an 'Edit' item, the handler of which calls:
Code: [Select]procedure TMainForm.OpenSelectedSourceFile();
begin
  if self.sources_filelistbox.SelCount = 1 then
    self.OpenInEditor(self.sources_filelistbox.FileName)
  else
    MessageDlg ('No file selected', 'You must first select a file from
the Sources list.', mtError,
                 [mbOk],0)
end;where my TFileListBox is called sources_filelistbox)

Thinking that what was happening was that the popup handling was
taking place before the mouse down handling, I disabled the popup menu
from the Object Inspector and tried popping it up manually:

Code: [Select]procedure TMainForm.sources_filelistboxMouseDown(Sender:
TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
var item:integer;
begin
  if Button = mbRight then
  begin
    item:=self.sources_filelistbox.ItemAtPos(Point(X,Y),true);
    if item>-1 then
    begin
      self.sources_filelistbox.Selected[item]:=true;
      sources_popupmenu.PopUp();
    end;
  end;
end;
This also makes the popup routines think they are working with the
'old' selection (?!) and introduces another oddity: Only every odd
numbered right click brings up the popup. In other words, the first
right click selects the item under the pointer and pops up the menu,
the second only selects an item, the third selects the item and pops
up the menu, the fourth only selects an item, etc.

I also trued a small variation of the above that does NOT select the
clicked item:
Code: [Select]procedure TMainForm.sources_filelistboxMouseDown(Sender:
TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
var item:integer;
begin
  if Button = mbRight then
  begin
    item:=self.sources_filelistbox.ItemAtPos(Point(X,Y),true);
    if item>-1 then
    begin
      //self.sources_filelistbox.Selected[item]:=true;
      sources_popupmenu.PopUp();
    end;
  end;
end;
This fixes the 'old selection' problem but not the 'every other right
click' problem.

I am confused but suspect I am missing something pretty basic here.

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theo · 2010-06-26 06:52

Pleas see if this is already reported in the bugtracker.
If not, make a bug report with a minimal compilable project showing
this bug.
http://bugs.freepascal.org/view_all_bug_page.php?project_id=1