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Including Components into a StatusBar (Views: 102)


Problem/Question/Abstract:

The TStatusbar usually does not allow to place components on itself. But sometimes it would be very fine to add -for example- a TProgressBar on a Statusbar.

This Article shows how to add components to a TStatusbar and how to fit it into one of the Statusbar-Panels.

Answer:

There are (at least) two ways to add Components on your Statusbar:

1. Create an own Statusbar-Object

Create your own Statusbar and allow to add components on it. This is possible in overriding the Create-Constructor:

type
  TMyStatusBar = class(TStatusBar)
  public
    constructor Create(AOwner: TComponent); override;
  end;

implementation

constructor TMyStatusBar.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  ControlStyle := ControlStyle + [csAcceptsControls];
  //that’s all !!
end;

That’s all! Now this component accept other components as “Children” and you can put them at design-time onto the statusbar!

But I don’t like this way very much because you have to use this new component. I prefer to use the “old” components and manipulating them a little bit. So lets have a look to my favourite way:

2. “Adopt” the other component

The simplest way to include components to a statusbar is to adopt the component! Place the TStatusbar on your Form, also place the Progressbar (or other component you wish to include on your Statusbar) on the form (!). Then do this in the “OnShow” Event of the Form:

Progressbar1.Parent := statusbar1;
Progressbar1.top := 1;
Progressbar1.left := 1;

Now the Progressbar is “adopted” by the Statusbar.

But unfortunatley it doesn’t look very nice because the Progressbar is larger than the panel and the position is not correct. So we have to determine the exact position of the Progresbar by using the Statubar’s border, width and height. (We have to add this code to the “OnShow” Event of the form, because in the “OnCreate” event still no Handles are avalible.)

procedure TForm1.FormShow(Sender: TObject);
var
  r: TRect;
begin
  Statusbar1.perform(SB_GETRECT, 0, integer(@R));
  //determine the size of panel 1

//SB_GETRECT needs Unit commctrl
// 0 = first Panel of Statusbar; 1 = the second and so on.

  progressbar1.parent := Statusbar1; //adopt the Progressbar

  progressbar1.top := r.top; //set size of
  progressbar1.left := r.left; //Progressbar to
  progressbar1.width := r.right - r.left; //fit with panel
  progressbar1.height := r.bottom - r.top;

end;

Now the Progressbar fits exactly into the first panel of the statusbar! If you want to use the second or another panel, you only have to change the parameter of the “perform” command.

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