CTreeCtrl 'TVN_ITEMCHANGED ' not getting fired when item checkbox is clicked in windows xp? - mfc

Question

I am having a tree control and the Tree control consists of a Root node
and that root node consists of one child node inturn this child node consists of 3 nodes.
This treecontrol is on a propertypage and in this after I click on any of the checkbox I am
enabling the wizard buttons.And in the event handler to TVN_ITEMCHANGED I enabled the sheet
buttons.
When I had run my application and after checking a node of treecontrol I am not able to enable the
sheet buttons.I had seen the code is absolutely fine where I am checking the check state of the node
and enabling the sheet buttons.I started debugging my code and first it was NM_CLICK is getting fired
and then I was expecting the TVN_ITEMCHANGED event to get fired but it is not at all getting fired.
I have no idea why this event is not getting fired,and the environment I am using is WindowsXP.
I had run my application on windows7 ,windows 8,windows vista.There it is working as expected,but in XP only
I figured out this behaviour.
Can anyone please help me to get this problem resolved.

Answer 1

According to MSKB you don't get a specific notification when the checkbox is clicked.
On a TreeView control with the TVS_CHECKBOXES style, there is no
notification that the checked state of the item has been changed.
There is also no notification that indicates that the state of the
item has changed. However, you can determine that the user has clicked
the state icon of the item and act upon that.
Quoting from that article:
When the user clicks the check box of a TreeView item, an NM_CLICK
notification is sent to the parent window. When this occurs, the
TVM_HITTEST message returns TVHT_ONITEMSTATEICON. The TreeView control
uses this same condition to toggle the state of the check box.
Unfortunately, the TreeView control toggles the state after the
NM_CLICK notification is sent.
You can post a user-defined message to the same window that is
processing the NM_CLICK notification, and treat this user-defined
message as a notification that the checked state has changed.
Following is sample code that illustrates how this can be
accomplished:
With the associated example code:
#define UM_CHECKSTATECHANGE (WM_USER + 100)
case WM_NOTIFY:
{
LPNMHDR lpnmh = (LPNMHDR) lParam;
TVHITTESTINFO ht = {0};
if(lpnmh->code == NM_CLICK) && (lpnmh->idFrom == IDC_MYTREE))
{
DWORD dwpos = GetMessagePos();
// include <windowsx.h> and <windows.h> header files
ht.pt.x = GET_X_LPARAM(dwpos);
ht.pt.y = GET_Y_LPARAM(dwpos);
MapWindowPoints(HWND_DESKTOP, lpnmh->hwndFrom, &ht.pt, 1);
TreeView_HitTest(lpnmh->hwndFrom, &ht);
if(TVHT_ONITEMSTATEICON & ht.flags)
{
PostMessage(hWnd, UM_CHECKSTATECHANGE, 0, (LPARAM)ht.hItem);
}
}
}
break;
case UM_CHECKSTATECHANGE:
{
HTREEITEM hItemChanged = (HTREEITEM)lParam;
/*
Retrieve the new checked state of the item and handle the notification.
*/
}
break;