ElTreeInplaceDateTimePicker on ElXTree raises Contol '' has no parent window. LMD ElPack 2018

Huge TNS

If the DateTimePicker is editing, and you click outside it on the tree, it raises this error. I AM on the LMD ElPack 2018.0(22-01/2018).

On Rad Studio, Delphi, Tokyo 10.2, update 2.

An example with instructions is attached. 

Best regards,

Louis Kriel

Huge TNS

Bug Fix PLEASE. I am trying to find a workaround, but unsuccessful so far.

Eugene Balabuev (LMD)

<Removed>

Eugene Balabuev (LMD)

I've checked more and can now confirm the issue (happen in 10.2 only).

To workaround please add "if HandleAllocated then" before "inherited" in TElDateTimePicker.WMKillFocus method:

procedure TElDateTimePicker.WMKillFocus(var Msg : TWMKillFocus);  { private }

begin

  FFocused := false;

  if HandleAllocated then // <-------------

    inherited;

  if LMDSIWindowsVistaUp and IsThemed and HandleAllocated then

    DrawFlatBorder;

  if Flat then

    if HandleAllocated then

      UpdateFrame;

...

Louis Kessler

The same thing happened to me, but using TElTreeInplaceEdit.   I am using Delphi 10.2.2

The fix for TElDateTimePicker that you give above doesn't work here since there is no WMKillFocus event in ElTreeStdEditors.

Can you confirm this problem and suggest a fix please.

Eugene Balabuev (LMD)

I connot reproduce this. For me simple text inplace editing (TElTreeInplaceEdit) works fine. Can you specify your setup and steps to reproduce more precisely.

Louis Kessler

Thanks, Eugene:

I have a TElXTree on a form with 7 sections. The 2nd section is a Text field that is marked Editable. I have a TElTreeInplaceEdit on the form associated with the TElXTree.

I use 3 events for the InplaceEdit:

- InplaceEditBeforeOperation  

- InplaceEditAfterOperation

- InplaceEditEditorOnKeyUp

The first two are harmless. I don't know if the 3rd is causing the problem, but I'll give you my code::

procedure TOrganizePages.TagsDisplayInplaceEditEditorOnKeyUp(Sender: TObject;
  var Key: Word; Shift: TShiftState);
begin
  DoEditorOnKeyUp(TagsList, TDisplayAsCol, TCustomElEdit(Sender), Key, Shift);
end;

I do this to allow processing of some special keys on your form:

procedure DoEditorOnKeyUp(ElXTree: TElXTree; const EditColumn: integer; var ElEdit: TCustomElEdit;
      var Key: word; Shift: TShiftState);
var
  CurItem: TElXTreeItem;
  INext: Integer;
begin

case Key of
  VK_F2:
    ElXTree.EndEdit(false);

  $41: { A part of Ctrl-A }
    if ssCtrl in Shift then { Ctrl part of Ctrl-A }
      ElEdit.SelectAll;

  $5a: { Z part of Ctrl-Z }
    if ssCtrl in Shift then { Ctrl part of Ctrl-Z }
      ElEdit.Undo;

  VK_PRIOR: begin
    ElXTree.Items.BeginUpdate;
   { Note: this isn't perfect from near the bottom of the tree, but it's close enough }
    INext := ElXTree.TopIndex -(ElXTree.BottomIndex - ElXTree.ItemFocused.AbsoluteIndex);
    if ElXTree.BottomIndex >= (ElXTree.Items.Count - 1) then
      INext := INext - 1;

    if INext < 0 then INext := 0;
    ElXTree.EndEdit(false);
    ElXTree.Perform(WM_VSCROLL, SB_PAGEUP, 0);
    ElXTree.ItemFocused := ElXTree.Items[INext];
    ElXTree.Items.EndUpdate;
  end;

  VK_NEXT: begin
    ElXTree.Items.BeginUpdate;
    INext := ElXTree.BottomIndex + ElXTree.ItemFocused.AbsoluteIndex - ElXTree.TopIndex;
    if INext > ElXTree.Items.Count then INext := ElXTree.Items.Count - 1;
    ElXTree.EndEdit(false);
    ElXTree.Perform(WM_VSCROLL, SB_PAGEDOWN, 0);
    ElXTree.ItemFocused := ElXTree.Items[INext];
    ElXTree.Items.EndUpdate;
  end;

  VK_HOME: begin
    if ssCtrl in Shift then { Ctrl part of Ctrl-Home } begin
      ElXTree.Items.BeginUpdate;
      ElXTree.EndEdit(false);
      ElXTree.ItemFocused := ElXTree.Items[0];
      ElXTree.Items.EndUpdate;
      ElXTree.ItemFocused.MakeVisible;
    end;
  end;

  VK_END: begin
    if ssCtrl in Shift then { Ctrl part of Ctrl-End } begin
      ElXTree.Items.BeginUpdate;
      ElXTree.EndEdit(false);
      ElXTree.ItemFocused := ElXTree.Items[ElXTree.Items.Count-1];
      ElXTree.Items.EndUpdate;
      ElXTree.ItemFocused.MakeVisible;
    end;
  end;

  VK_DOWN, VK_RETURN:
    begin
      ElXTree.Items.BeginUpdate;
      CurItem := ElXTree.ItemFocused;
      CurItem := CurItem.GetNext;
      while CurItem <> nil do begin
        ElXTree.ItemFocused := CurItem;
        if CurItem.IsVisible and CurItem.AllowEdit then begin
          ElXTree.EndEdit(false);
          ElXTree.EditItem(CurItem, EditColumn);
          break;
        end;
        CurItem := CurItem.GetNext;
      end;
      if CurItem = nil then { at the bottom }
        ElXTree.EditItem(ElXTree.ItemFocused, EditColumn);
      ElXTree.Items.EndUpdate;
      ElXTree.ItemFocused.MakeVisible;
      Key := 0;
    end;

  VK_UP:
    begin
      ElXTree.Items.BeginUpdate;
      CurItem := ElXTree.ItemFocused;
      CurItem := CurItem.GetPrev;
      while CurItem <> nil do begin
        ElXTree.ItemFocused := CurItem;
        if CurItem.IsVisible and CurItem.AllowEdit then begin
          ElXTree.EndEdit(false);
          ElXTree.EditItem(CurItem, EditColumn);
          break;
        end;
        CurItem := CurItem.GetPrev;
      end;
      if CurItem = nil then { at the top }
        ElXTree.EditItem(ElXTree.ItemFocused, EditColumn);
      ElXTree.Items.EndUpdate;
      ElXTree.ItemFocused.MakeVisible;
      Key := 0;
    end;
  end;
end;

If I change text in the field and just hit Enter, or any of the keys in the above routine (e.g. arrow up, Home, etc) , there is no problem and it works as it should.

But if I change text in the field and then use the mouse to click on another field or any other window, when I'm in the Delphi debugger, it brings up a Debugger Exception Notification window that says: "Project raised exception class EInvalidOperation with message 'Control '' has no parent window' leading to the Windows exception "Control '' has no parent window."

If I break the debugger a that exception, the line in ElTreeStdEditors it was at was the last line of EditorWndProc:
     SaveWndProc(Message);

And now that you've got me to look, I see that I had to modify that routine so that I could catch the Return key myself.

This is the routine I use:

procedure TElTreeInplaceEdit.EditorWndProc(var Message : TMessage);
var
  InputValid : boolean;
begin
  if Message.Msg = WM_GETDLGCODE then
  begin
    inherited;
    Message.Result := Message.Result or DLGC_WANTCHARS or DLGC_WANTARROWS or DLGC_WANTALLKEYS;
  end
  else
  if Message.Msg = WM_KEYDOWN then
  begin
    TriggerKeyDown(TWMKey(Message));
    with TWMKey(Message) do
    begin
      if KeyDataToShiftState(KeyData) = [] then
      begin

(* LK 31 May 2011 - Removed VK_RETURN so I can catch it myself
        if CharCode = VK_RETURN then
        begin
          InputValid := true;
          FEditing := false;
          TriggerValidateResult(InputValid);
          FEditing := true;
          if InputValid then
          begin
            CompleteOperation(true);
            CharCode := 0;
            exit;
          end
          else
            Editor.SetFocus;
          CharCode := 0;
        end
        else
// LK 31 May 2011 - End of Removed VK_RETURN so I can catch it myself *)

        if CharCode = VK_ESCAPE then
        begin
          CompleteOperation(false);
          CharCode := 0;
          exit;
        end;
      end;
    end;
  end
  else
  if (Message.Msg = WM_CANCELMODE) or
     ((Message.Msg = CM_CANCELMODE) and
      (TObject(Pointer(Message.lParam)) <> Editor)) or
      (Message.Msg = WM_KILLFOCUS) then
    if FEditing then
    begin
      if THackElTree(Tree).FExplorerEditMode then
      begin
        EndEditWithInputChecked;
      end
      else
        CompleteOperation(false);

      if Message.Msg <> CM_CANCELMODE then
        SendMessage(THackElTree(Tree).View.Handle, CM_EXIT, 0, 0);
    end;
  SaveWndProc(Message);
end;

This worked without problem until recently, which I blame on Delphi 10.2.2.  When I saw this other post with the exact same problem, I thought there must be a simple solution.  Maybe 10.2.3 which just came out will fix the issue, but it's not nice when they make updates that breaks your (or my) code. 

If you can see what might be causing this, or a possible patch for this, please let me know.   

Also feel free to also give me any suggestions to capture keys like I'm doing if you think there's a better way.

If you need more screenshots or code than I can supply here, please email me:  lkessler at lkessler dot com

Thanks.

Louis Kessler
Winnipeg, Manitoba, Canada

Eugene Balabuev (LMD)

Will issue occure without event handlers?

Louis Kessler

Good question.  

I removed the handler, and yes, the issue still happens when editing the text and (without pressing Enter) clicking anywhere outside what was edited.

And just to make sure, I added back the code that I removed, and the issue still happens.  So it does not appear to have anything to do with the handler I added or the changes I made.

Everything was working fine less than a year ago with my handler and code changes. I am fairly certain it is a similar problem to DateTimePicker from the original post on this thread that you found a fix for, likely caused by Delphi 10.2.x.

Louis

Louis Kessler

Eugene,

The debug trace includes the following Elpack routines:

ElXTree.TElXTreeView.WndProc - the last line:   inherited
which calls a few vcl routines and then

ElXTree.TElXTreeView.WMLButtonDown, and then 

ElXTree.TElXTreeView.IntLButtonDown - the SetFocus at the 3rd line from the bottom, and then

ElXTree.TElXTreeView.SetFocus - the "inherited SelfFocus" line

I tried, as you suggestied to Louis Kriel above, to put "if HandleAllocated then" before any "inherited" lines in any of these routines. That did not fix the issue.

I also went to ElXTree and tried the same, putting "if HandleAllocated then" before any "inherited" lines in:

TElXTreeView.WMKillFocus,

TCustomElXTree.WMKillFocus,

TElXTreeView.WMSetFocus,

TCustomElXTree.WMSetFocus

but none of those fixed the issue either.

Louis

Louis Kessler

I found it!!!!!!!!!!!!!!

At the bottom of TElTreeInplaceEdit.EditorWndProc is:

  if (Message.Msg = WM_CANCELMODE) or
     ((Message.Msg = CM_CANCELMODE) and
      (TObject(Pointer(Message.lParam)) <> Editor)) or
      (Message.Msg = WM_KILLFOCUS) then
    if FEditing then
    begin
      if THackElTree(Tree).FExplorerEditMode then
      begin
        EndEditWithInputChecked;
      end
      else
        CompleteOperation(false);
      if Message.Msg <> CM_CANCELMODE then
        SendMessage(THackElTree(Tree).View.Handle, CM_EXIT, 0, 0);
    end;
  SaveWndProc(Message);

I noticed similar code in:

TElTreeInplaceMemo.EditorWndProc  and

TElTreeInplaceCheckBox.EditorWndProc

except the EditorWndProc procedure had a bit different code.

        CompleteOperation(false);

It had:  

      begin
        CompleteOperation(false);
        exit;
      end;

which exits without executing the SaveWndProc(Message) line.

I did that in the EditorWndProc procedure, and my issue vanished.

Please compare the 3 routines I list above and see if you agree that this is the correct fix. 

Thanks.

Louis

So in 

Louis Kessler

I found another case where I still got the error.  So I changed my fix above, to this:

  if (Message.Msg = WM_CANCELMODE) or
     ((Message.Msg = CM_CANCELMODE) and
      (TObject(Pointer(Message.lParam)) <> Editor)) or
      (Message.Msg = WM_KILLFOCUS) then
    if FEditing then
    begin
      if THackElTree(Tree).FExplorerEditMode then
      begin
        EndEditWithInputChecked;
      end
      else
        CompleteOperation(false);
      if Message.Msg <> CM_CANCELMODE then
        SendMessage(THackElTree(Tree).View.Handle, CM_EXIT, 0, 0);

      exit:
    end;
  SaveWndProc(Message);

I added that "exit" line near the bottom.  It now prevents the SaveWndProc line from being called whenever Canceling or Killing the focus.

Louis

Eugene Balabuev (LMD)

Thanks for report. Your modification has been incorporated.