Re: custom undo items?

Return to index

Author

Message

Sergey Tkachenko

Posted: 10/24/2004 17:56:53

type

  TRVUndoBackColor = class(TRVUndoInfo)

    private

      FColor: TColor;

    public

      procedure Undo(RVData: TRichViewRVData); override;

      function RequiresFormat: Boolean; override;

  end;

function TRVUndoBackColor.RequiresFormat: Boolean;

begin

  Result := False;

end;

procedure ChangeRichViewEditColor(RVData: TRichViewRVData; Color: TColor);

var ui: TRVUndoBackColor;

    list: TRVUndoList;

    rve: TCustomRichViewEdit;

begin

  list := TRVEditRVData(RVData).GetUndoList;

  if list<>nil then begin

    ui := TRVUndoBackColor.Create;

    ui.FColor := TRichViewEdit(RVData.GetRootData.GetParentControl).Color;

    list.AddInfo(ui)

  end;

  rve := TCustomRichViewEdit(RVData.GetRootData.GetParentControl);

  rve.Color := Color;

  while rve<>nil do begin

    rve.Invalidate;

    rve := TCustomRichViewEdit(rve.InplaceEditor);

  end;

end;

procedure TRVUndoBackColor.Undo(RVData: TRichViewRVData);

begin

  ChangeRichViewEditColor(RVData, FColor);

end;

How to test:

procedure TForm3.Button1Click(Sender: TObject);

begin

  RichViewEdit1.BeginUndoGroup(rvutModifyItem);

  { Note: rvutModifyItem may be not appropriate,

  but there are no appropriat standard constant

  for this undo action. You can use BeginUndoCustomGroup,

  though. }

  ChangeRichViewEditColor(RichViewEdit1.RVData, clRed);

end;

>

> Hi,

>

> If offer the option to change the entire background of the RVE in my

application

> by changing rve.color (e.g. rve.color:=clred). However when I change the

> rve to a new color this action is not undo-able. Changing rve text or

paragraph

> color can be undone fine.

>

> Can you suggest a way to make it undo-able, or should I be changing the

entire

> background color some other way?

>

> Thanks