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OnMouseDown in TPopupMenu

jmstolting
jmstolting asked
on
Medium Priority
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Last Modified: 2010-04-04
I need to be able to react to mousedowns on menu items that have subitems.

normally, the menu only reacts (closes) when the user clicks on a leaf (a menu item without subitems).

The only available event in TMenuItem is OnClick, but this also gets triggered if an item is highlighted.

Can anyone show me how to implement this handler, 'cause i'm slightly stuck (understatement of the year)
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Author

Commented:
Adjusted points to 200

Commented:
You will need to capture the WM_MenuSelect message.

Author

Commented:
ygolan :

thanks for your proposed answer.

WM_MenuSelect won't work for two reasons :

1. The T(Popup)Menu triggers this message on two occasions. [A] the user clicks on a menuitem which doesn't have any subitems (so far so good) and [B] the user positions the mousecursor over an item which has subitems. (automatic opening of the sub-menu). I need to be able to determine if the user generates a mousedown over a menuitem wether it has subitems or not.

2. when the user clicks on a menuitem which has subitems, windows doesn't send _any_ message to the menu.WinProc handler.

-----

I know, this problem is slightly bigger than I first thought it to be. oh well, another 101 points then.

ps: I think using a mousehook should do the trick, but I don't have the time to explore this subject extensively.

jeroen

Author

Commented:
Adjusted points to 301

Commented:
Which version of Delphi do you use?I think it's a difficult task to handle mouse events on a menu, because it's made to be a MENU (select one, and send back the result)It would help if you write down exactly what you want to do.

Author

Commented:
Gabor,

I'm using Delphi 3.0 professional.

What I want to do is this : I want users to be able to select items from a tree, represented by a (popup)menu.

When a user selects an item, all parents of this item should be selected. This isn't difficult if the user would only able to select the leaves of the tree, but that's not what I want.

They should be able to select an item, for example, halfway down the tree. If this item has children, my problem occurs...

Thanks for your reaction,

jeroen.
Commented:
I have found what you want.

1. To avoid to show submenus make all subitems' Visible property to FALSE at initialization.

2. You can use the OnClick event to handle selections.

This is not enought for you, because you want to handle mouse-button event too.
You can determine if the OnClick event is occured by the left button with using GetAsyncKeyState API function:

{OnClick event}
...
if GetAsyncKeyState(VK_LBUTTON)<0 then begin
  {you can do everithing you want, for example make subitems' Visible property to true}
end;
...

It works, I have tried it.

Good luck!

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