Scrollbar Popup Menu

[standay]

Sergey,

Would you have any idea on how to get a popupmenu to show when the rve vertical scrollbar is right clicked? I've looked all over and tried things and nothing works. Just wondered if you had any ideas.

Thanks

Stan

[Sergey Tkachenko]

AFAIK, it can be implemented by handling WM_NCRBUTTONDOWN message in rve. But TRichView does not process this message, so it can be done only in an inherited component.
Or you can hide a scrollbar (VScrollVisible = False) and use your own external scrollbar instead.

[standay]

Hi Sergey,

Yes, WM_NCRBUTTONDOWN (along with a HitTest check) works. My app already lets me choose between using a native scrollbar or an external one. Adding a popup to the external one is easy, but I was stumped with how to add it to the native scrollbar.

Here's what I did in case someone else wants to try it. I just subclassed the rve so I didn't have to make a new component:

Code: Select all

type
  TRichViewEdit = class( RVEdit.TRichViewEdit )
  private
    procedure WMNCRButtonDown(var Msg : TWMNCRButtonDown); message WM_NCRBUTTONDOWN;
  end;
...
//http://www.delphicorner.f9.co.uk/articles/forms3.htm
procedure TRichViewEdit.WMNCRButtonDown(var Msg : TWMNCRButtonDown);
begin
  if Form1.rve.VScrollVisible then
  if (Msg.HitTest = HTVSCROLL) then
  begin
    Form1.PopupMenu1.Popup( Mouse.CursorPos.X,Mouse.CursorPos.Y );
  end;
  if Form1.rve.HScrollVisible then
  if (Msg.HitTest = HTHSCROLL) then
  begin
    Form1.PopupMenu1.Popup( Mouse.CursorPos.X,Mouse.CursorPos.Y );
  end;
end;

Works great and is just what I was after. Thanks again.

Stan

[standay]

Hi Sergey,

Probably no one cares about this but I thought I'd post a follow up. While subclassing the TRichViewEdit let me show a popupmenu when right-clicking the rve scrollbar, it was causing some unintended problems elsewhere in my app. It would work OK in a simple project, but my project is not a simple one.

So I did this instead. Since the rve sends the WM_NCRBUTTONDOWN out when its scrollbar is clicked, I handled that message in an appication events message event instead of the rve itself.

Code: Select all

procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;
  var Handled: Boolean);
var
  Pt: TPoint;
  r: TRect;
begin

  //Processing WM_NCRBUTTONDOWN this way let me put a popupmenu on the native OS scrollbar.
  //Panel7 is the rve parent component
  Pt := Panel7.ScreenToClient( Mouse.CursorPos );
  r := Panel7.ClientRect;
  if Msg.message = WM_NCRBUTTONDOWN then
  begin
    r := Panel7.ClientRect;
    //Restrict this to just the vertical scrollbar:
    r.Left := r.Right - GetSystemMetrics( SM_CYVSCROLL );
    if PtInRect( r, Pt ) then
    begin
      //ReleaseCapture; //So far, not needed...
      //Only show the scroll popup if the native OS scrollbar is visible:
      if Form1.rve.VScrollVisible then
      begin
        //Use if VScrollMax > 0 here if you only want to show the popup
        //if it is active.
        ScrollPopup.Popup( Mouse.CursorPos.X,Mouse.CursorPos.Y );
      end;
      //The key to making this work: Shut off this message:
      Handled := true;
    end;
  end;

This now works without subclassing or making a new component. Maybe it will help someone else wanting to do this.

Stan