Delphi Custom popup/dropdown, how?

问题

I want to make a custom dropdow/popup menu with a shadow nicely beneath it. The problem is that it is not a standard menu and I need to put some components on the popup/dropdown. So basically I want a dropdown I can do whatever I want with, not being limited to simple menuitems. I want it to act like a normal popupmenu problem is where do I start. Any solutions? References?

回答1:

It sounds like you want a form that looks like a popup menu, but contains components.

It is easier if you have a component that has an OnMouseDown event, like the TPanel shown in this sample, and you just pop up a second form which contains the controls you wanted to pop up:

procedure TForm3.JvPanel1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if Button=mbRight then
        FDown := true
  else
        FDown := false;
end;

procedure TForm3.JvPanel1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  pt:TPoint;
begin
  if Button=mbRight then begin
        FDown := true;
        pt.X := jvPanel1.Left;
        pt.Y := jvPanel1.Top+jvPanel1.Height;


        pt := ClientToScreen(pt);
        Form4.Position := poDesigned;
        Form4.BorderStyle := bsNone;
        Form4.Left := pt.X;
        Form4.Top := pt.Y;
        Form4.Show;
  end;

end;

That handles the form showing itself, and positioning itself to look like a popup. the second form hiding itself, is easy too:

procedure TForm4.FormDeactivate(Sender: TObject);
begin
 Hide;
end;

alt text http://img718.imageshack.us/img718/8171/formlookslikepopup.png

回答2:

You can use TPopupMenu and provide custom drawing. This is done by setting

PopupMenu1.OwnerDraw := True;

Then code the OnMeasureItem() or OnAdvancedDrawItem() Event to determine the size you need for the custom painting. Then code the OnDrawItem() Event to paint the canvas as desired.

回答3:

For what it is worth, the drop shadow aspect of the popup has now been tackled and solved in this question.

来源：https://stackoverflow.com/questions/2992933/delphi-custom-popup-dropdown-how