How to create a button with drop-down menu?

问题

Is there a way to show IE/Firefox Back button style, dropdown menu button?

回答1:

I am assuming you mean a button that drops down a menu when clicked.

You can also just manually code your button click to drop down a TPopupMenu under it.

Example: Drop anything with a TClickEvent (maybe a TButton) and a TPopupMenu on your form. Add some menu items. Then add the following OnClick event handler:

procedure TForm86.Button1Click(Sender: TObject);
var
  button: TControl;
  lowerLeft: TPoint;
begin
  if Sender is TControl then
  begin
    button := TControl(Sender);
    lowerLeft := Point(button.Left, button.Top + Button.Height);
    lowerLeft := ClientToScreen(lowerLeft);
    PopupMenu1.Popup(lowerLeft.X, lowerLeft.Y);
  end;
end;

And viola! Just like magic. You could wrap it all up in a component if you plan to reuse it. Maybe even sell it online.

Note: If you want a delay, then extract that code in another method and then set a timer OnClick and turn the timer of OnMouseLeave. Then if the timer fires you can call the extracted method. Not sure how you would do it on a keyboard click. I don't know if Firefox, etc. supports that either.

回答2:

Jim's answer is great, but didn't quite work for me at first. ClientToScreen uses Form86's method, which is only correct if the button is directly on the form. It should be the button's ClientToScreen method that is called, like this:

procedure TForm86.Button1Click(Sender: TObject);
var
  button: TControl;
  lowerLeft: TPoint;
begin
  if Sender is TControl then
  begin
    button := TControl(Sender);
    lowerLeft := Point(0, button.Height);
    lowerLeft := button.ClientToScreen(lowerLeft);
    PopupMenu1.Popup(lowerLeft.X, lowerLeft.Y);
  end;
end;

This works no matter where the button is.

回答3:

Sure. Put a toolbar on the page. Right-click on the toolbar, add a button. Set the button's style to tbsDropDown. Put a PopupMenu on the page. Double click on the PopupMenu to define menu items. Then, go back to the button you created and set its DropdownMenu property to point to the PopupMenu you just created.

回答4:

If you don't want to use a toolbar, the raize (www.raize.com) and express editors (www.DevExpress.com) libraries have components that can do this.

来源：https://stackoverflow.com/questions/235498/how-to-create-a-button-with-drop-down-menu

标签

Delphi

button

popupmenu