Tree-View problem

[sasho648]

Hi all, I'm new here.

First I really get confused with the WM_NOTIFY message and the variables structures which inputs("A pointer to an NMHDR structure that contains the notification code and additional information. For some notification messages, this parameter points to a larger structure that has the NMHDR structure as its first member."). I actually want to catch when the user changes an item in the Tree-View. I use for this the NM_CLICK message but I found this isn't effective for changing item selection with the keyboard. That's way I write this but I doesn't working:

case WM_NOTIFY:
        {
            if(((LPNMHDR)lParam)->idFrom==IDC_TREE1||((LPNMTREEVIEW)lParam)->hdr.idFrom==IDC_TREE1)
                if(((LPNMTREEVIEW)lParam)->hdr.code==TVN_SELCHANGING||((LPNMHDR)lParam)->code==NM_CLICK)
                {
			//Do my code		
                }
         }
         break;

I will be happy if you help me an explain me why this code doesn't work.

[sasho648]

Any answers? Did this community don't know anything about the Tree-View notifications just like the web? Or if this is old is there something like new, free from bugs Tree-View like control?

[guestgulkan]

See if this helps
http://msdn.microsoft.com/en-us/library/windows/desktop/bb773544(v=vs.85).aspx

Anyway it looks like your logic is flawed.
I'm writing this from my phone and it's driving me nuts
so I'll edit it later from my pc.

(and a little less whineing in future -thanks)

[sasho648]

No I come just from this. I'll really not more using Win32 but for now I need this for my app version which I currently releasing. Anybody help me? (what "whinEing"?)

[guestgulkan]

OK I created a test project which created just one treeview.
(As I only created just one control which was the treeview I did not check whichcontrol the WM_NOTIFY message is coming from - but you should add the check to your code if needed)

Example 1

    case WM_NOTIFY: //we will trap this to do stuff with the treview
        {

            LPNMHDR  pnmh = (LPNMHDR)lParam;
            switch (pnmh->code)
            {

            case TVN_SELCHANGED:
                {
                    LPNMTREEVIEW pnmtv = (LPNMTREEVIEW) lParam; // 
                    //Test 1 - Check if selection was changed by keyboard
                    if (pnmtv->action ==TVC_BYKEYBOARD)
                    {
                        SetWindowText(hWnd, _T("Selection changed by keystroke"));
                    }
                    //test 2 - if not selected by keyboard  then check for mouse selection
                    else if(pnmtv->action ==TVC_BYMOUSE )
                    {
                        SetWindowText(hWnd, _T("Selection changed by mouse"));
                    }
                    else //if neither of the above
                    {
                        SetWindowText(hWnd, _T("Selection changed by Act Of GOD"));
                    }

                    break;
                }

            default:
                break;
            }



            return 0;
        }

Example 2;

    case WM_NOTIFY: //we will trap this to do stuff with the treview
        {

            LPNMHDR  pnmh = (LPNMHDR)lParam;
            switch (pnmh->code)
            {

            case TVN_SELCHANGED:
                {
                    LPNMTREEVIEW pnmtv = (LPNMTREEVIEW) lParam; // 
                    //Test 1 - Check if selection was changed by keyboard or mouse
                    if (pnmtv->action ==TVC_BYKEYBOARD || pnmtv->action ==TVC_BYMOUSE )
                    {
                        SetWindowText(hWnd, _T("Selection changed by keystroke or mouse"));
                    }

                    else //if not by keyboard or mouse
                    {
                        SetWindowText(hWnd, _T("Selection changed by Act Of GOD"));
                    }

                    break;
                }

            default:
                break;
            }

            return 0;
        }
    

[sasho648]

Sorry this don't work for me. Maybe this work only on UNICODE characters?

[guestgulkan]

Sorry this don't work for me. Maybe this work only on UNICODE characters?

is not really a good enough reply.

Im sure my use of the TVN messages and action code is correct and the examples are correct.

So what did not work for you??

[modoran]

Maybe OP does not include <tchar.h> header, as few tutorials uses it .