I have a window which has a CTreeCtrl. A user can right-click any element and display a context menu. From there they can choose to delete the entry. Something like this:
Here is a snippet of the context menu item handler:
void CAssignHistoryDlg::OnDeleteFromAssignmentHistory()
{
CString strINI = theApp.GetAssignHistoryPath();
HTREEITEM hItem = m_treeHistory.GetSelectedItem();
CString strName, strDeletedName, strEntry;
if (m_treeHistory.GetParentItem(hItem) != nullptr)
{
// The user has picked one of the history dates.
// So the parent should be the actual name.
hItem = m_treeHistory.GetParentItem(hItem);
// Now OK to proceed
}
strName = ExtractName(hItem);
GetParent()->EnableWindow(FALSE);
strEntry.Format(IDS_TPL_SURE_DELETE_FROM_ASSIGN_HIST, strName);
if (AfxMessageBox(strEntry, MB_YESNO | MB_ICONQUESTION) == IDNO)
{
The image shows my problem. If I first click on Test, so that it is selected and bright blue and then right-click, it shows Test in the popup message. This is fine. But ...
If the first name is initially selected, and I go ahead and directly right-click Test, even though it seems to go blue (as if selected), m_treeHistory.GetSelectedItem() is returning the original, first name. I think I am describing it not very well.
In short, I want to guarantee that I get the HTREEITEM for the item that the user right-clicked on. What I have is not 100% fool-proof.
If it helps, this is how I display the context menu:
void CAssignHistoryDlg::OnNMRclickTreeHistory(NMHDR *pNMHDR, LRESULT *pResult)
{
CMenu mnuContext, *pMnuEdit = nullptr;
CPoint ptLocal;
LPNMTREEVIEW pNMTreeView = reinterpret_cast<LPNMTREEVIEW>(pNMHDR);
GetCursorPos(&ptLocal);
mnuContext.LoadMenu( IDR_MENU_SM_ASSIGN_HIST_POPUP );
pMnuEdit = mnuContext.GetSubMenu( 0 );
if (pMnuEdit != nullptr)
{
pMnuEdit->TrackPopupMenu( TPM_LEFTALIGN|TPM_LEFTBUTTON,
ptLocal.x, ptLocal.y, this, nullptr );
}
*pResult = 0;
}
So to recap, at the moment the user must physically left click on a item in the tree to select it. Then they can right-click and it will offer to delete this person. But if they go ahead and just right-click on anyone, it will not offer to delete THAT person.
You can get the actual tree item at any given point using the HitTest() member of the CTreeCtrl class. Exactly how and where you do this will depend on your code design but, if you have a pointer to your CTreeCtrl (pwTree in the code below), then you can do something like this:
CPoint ptLocal;
GetCursorPos(&ptLocal);
pWTree->ScreenToClient(&ptLocal); // May not be required in certain handlers?
HTREEITEM hItem = pWTree->HitTest(ptLocal); // Remember to check for NULL return!
You can then either use the returned hItem directly, or use it to explicitly set the tree's selection (to that item), before doing any further processing.
The MS doc: https://learn.microsoft.com/en-us/cpp/mfc/reference/cwnd-class?view=vs-2019 doesn't have a "click" handler, it has CWnd::OnRButtonDblClk, CWnd::OnRButtonDown and CWnd::OnRButtonUp. Which one are you handling?
The reason for your defect might be that you don't let the tree control handle that right button event (to select that new item).
I would suggest to use CWnd::OnContextMenu instead.
I have an application in which double clicking over an image view area changes the layout of the image view. Also on single click a dot will be placed on the image.
My problem is, both functionality is working when double clicked.
Of course I know that, when a double click occurs the control first goes to LButtonDown. I don't want the dot functionality to work when double click occurs. I have been working around this for more than a week. Please help.
The easiest way to solve this is to build a finite-state machine for handling mouse clicks.
Basically, this will be a singleton object, which takes input from the mouse click events you're currently using.
It's output will be SingleClickDetected, DoubleClickDetected, ....
Red arrows indicate events which you are reporting to the rest of your application.
Parentheses indicate what event you are reporting.
Of course, this state machine will have to be modified if you have to deal directly with MouseDown and MouseUp events, instead of MouseClick events.
It will be slightly larger, but the idea is basically the same.
EDIT:
From the comments, it looks like Windows doesn't cleanly report single- vs double-clicks, and you need to separate them.
A state-machine for this scenario:
This is probably overkill for what you're trying to do, especially since most, if not all GUI-based programs in the history of everything have never ever used a double-click drag.
It does show the basic idea, and shows how you can extend your state machine to handle different types of button clicks.
Furthermore, if you wanted to, you could handle double-right-clicks, a drag that involves both left and right buttons, or any other scenario you could think of and incorporate into your UI.
I wrote the following code and it works.
UINT TimerId;
int clicks;
VOID CALLBACK TimerProc(HWND hWnd, UINT nMsg, UINT nIDEvent, DWORD dwTime)
{
KillTimer(NULL, TimerId);
if (clicks < 2 && !double_click){
MessageBox(hWnd, L"Show Widget", L"Widget", MB_OK);
}
clicks = 0;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc;
TCHAR szHello[MAX_LOADSTRING];
LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);
UINT uID;
UINT uMouseMsg;
uID = (UINT)wParam;
uMouseMsg = (UINT)lParam;
if (uMouseMsg == WM_LBUTTONDBLCLK){
double_click = true;
MessageBox(hWnd, L"Double click", L"CAPT", MB_OK);
return 0;
}
if (uMouseMsg == WM_LBUTTONDOWN){
double_click = false;
clicks++;
//single click opens context menu
if (clicks == 1){
TimerId = SetTimer(NULL, 0, 500, &TimerProc);
}
return 0;
}
,...
}
Try storing the timestamp of the last LButtonDown; if the time difference between the last timestamp and the timestamp produced in the current event is too short, you can just cancel your operation (but still store the new LButtonDown timestamp)
The only thing you can do is wait for a short amount of time each time you receive click event, and test if in the meantime the equivalent of a double click event doesn't occur before performing the single click response. This may be source to new bugs and unresponsive UI. Maybe try to change the user interaction to toss the problem away.
EDIT: The fact that you are working around this for more than a week is a symptom of bad user interaction design. A "double click" still means two clicks occurs, which means the application naturally should perform the operation of a single click. Check the ui of the apps installed on your desktop to verify this. Have you considered using a different user medium to trigger the UI response? For instance, you can use the right button to put the dot on the image.
#E.T's answer is spot-on. To implement something like that, you really need a timer running along with your message loop.
In my application I wanted to be able to distinguish mouse down/up from double click because I want a double click to not undo a drag operation (imagine selection box with left button drag and double click to zoom to fit).
The following code does this using PreTranslateMessage. I did not add the timer out of laziness. So the UI behaves a bit "funny" if you don't immediately move the mouse after the left button is held down. In my case, this is a minor issue.
BOOL MyWindow::PreTranslateMessage(MSG *pMsg)
{
//From https://msdn.microsoft.com/en-us/library/windows/desktop/ms645606(v=vs.85).aspx
//Double-clicking the left mouse button actually generates a sequence of four messages:
//WM_LBUTTONDOWN, WM_LBUTTONUP, WM_LBUTTONDBLCLK, and WM_LBUTTONUP
//So here's the problem. If an button up message arrives, we can't just
//take it, because it may be followed by a double click message. So we check
//for this.
//Ideally you need a timer - what happens if you don't get any messages
//after the button up or down? But here we get lazy and assume a message
//will come "soon enough".
static bool upMessageStored = false;
static bool dnMessageStored = false;
static MSG upMessage, dnMessage;
static bool processDnNow = false, processUpNow = false;
//This logic sequence absorbs all button up and down messages, storing them to be sent
//if something other than a double click message immediately follows.
if (!(pMsg->message == WM_LBUTTONDBLCLK ||
pMsg->message == WM_LBUTTONDOWN ||
pMsg->message == WM_LBUTTONUP) &&
(upMessageStored || dnMessageStored))
{
//If we receive any message other than double click and we've stored the messages,
//then post them.
Output::Message(L"Stored messages posted.\n");
if (upMessageStored)
{
processUpNow = true;
upMessageStored = false;
this->PostMessage(upMessage.message, upMessage.wParam, upMessage.lParam);
}
if (dnMessageStored)
{
processDnNow = true;
dnMessageStored = false;
this->PostMessage(dnMessage.message, dnMessage.wParam, dnMessage.lParam);
}
return TitlelessWindow::PreTranslateMessage(pMsg);
}
if (pMsg->message == WM_LBUTTONDOWN && !processDnNow)
{
Output::Message(L"WM_LBUTTONDOWN absorbed; message stored\n");
dnMessage = *pMsg;
dnMessageStored = true;
return TRUE; //swallow this message.
}
else if (pMsg->message == WM_LBUTTONUP && !processUpNow)
{
Output::Message(L"WM_LBUTTONUP absorbed; message stored\n");
upMessage = *pMsg;
upMessageStored = true;
return TRUE; //swallow this message.
}
else if (pMsg->message == WM_LBUTTONDBLCLK)
{
Output::Message(L"WM_LBUTTONDBLCLK; stored message discarded\n");
upMessageStored = false;
dnMessageStored = false;
processUpNow = false;
processDnNow = false;
}
//If we get here, we are processing messages normally. Be sure we clear the flags
//for up and down.
processDnNow = false;
processUpNow = false;
return ParentClass::PreTranslateMessage(pMsg);
}
I really liked the finite state machine answer BUT there is a flaw in it.
There is no such thing as "single click time" which you can exceed.
If you look at a the working of your mouse closely you will see that:-
single click not one event but = WM_LBUTTONDOWN, WM_LBUTTONUP which is independent of time in between, the appropriate action will take place anyway
Double-clicking the left mouse button actually generates a sequence of four messages: WM_LBUTTONDOWN, WM_LBUTTONUP, WM_LBUTTONDBLCLK, and WM_LBUTTONUP
so you should use the 3rd flag to your advantage
BTW, I am also working on something like this. Thanks!
I have a dialog box displayed when I press a menu item in the SDI window. In the Dialog box When i press OK button it should display "SUCESS" in the SDI window... In ONVIEW() i have to use pDC->TEXTOUT() but how to execute that statement on pressing OK button.. I am using visual C++ 6
you should define a user defined message and use PostMessage to call your method in SDI Window.
I am working on assumption that your dialog is modal.
You do not have to define or send any messages.
Retrieve data from the dialog.
Presumably you store 2D vector data in some kind of an array declared as a member variable of the dialog.
When OK button is pushed and copy data to a view’s member variable of the same type. Use it to draw whatever you desire.
void CSDIPopupSampleView::OnViewDialog()
{
CSimpleDlg dlg;
int iResponse = dlg.DoModal();
if(IDOK == iResponse)
{
//Copy data from a dialog here.
}
Invalidate(); // this will cause redraw
}
MFC doc/view architecture, sdi (more precisely multiple top-level windows).
In my view class, I set my "playground" (i.e. logical space) with SetScrollSizes(); Then I want to limit maximum frame window size to that of view's maximum size.
Here is what I'm doing but I think there might be better solution, please advice:
I'm implementing OnGetMinMaxInfo() in my CMainFrame. There I try to get active view's scroll sizes, and set lpMMI->ptMaxTrackSize appropriately. Below is the code:
void CMainFrame::OnGetMinMaxInfo(MINMAXINFO* lpMMI)
{
// Call base version:
CFrameWndEx::OnGetMinMaxInfo(lpMMI);
// Get active view:
CScrollView *pScrollView = (CScrollView *)GetActiveView();
if (pScrollView && pScrollView->IsKindOf(RUNTIME_CLASS(CMyFckinView)))
{
// Get total size of playground:
CSize sizePlayground = pScrollView->GetTotalSize();
// Test if the size is non-zero, i.e. there is at least one node displayed:
if (sizePlayground.cx && sizePlayground.cy/* && !IsPrintPreview()*/)
{
// Set maximum window size to match our playground size:
CRect rectClient, rectWindow;
pScrollView->GetClientRect(&rectClient);
this->GetWindowRect(&rectWindow);
if (rectWindow.top > -5000 && rectWindow.left > -5000) // Avoid when minimized...
{
lpMMI->ptMaxTrackSize.x = sizePlayground.cx + (rectWindow.Width() - rectClient.Width());
lpMMI->ptMaxTrackSize.y = sizePlayground.cy + (rectWindow.Height() - rectClient.Height());
return;
}
}
}
}
This works but has one problem: When print preview is displayed (standard MFC print preview), I obviously want to allow free window resizing, so I use runtime info GetActiveView()->IsKindOf(...) to determine that active view is really my view, and not print-preview's view (which is CPreviewViewEx). But when I close the print preview, OnGetMinMaxInfo is not called, so I'm unable to adjust frame size according to my view again. As soon as I move the window OnGetMinMaxInfo gets called again and correctly adjusts frame size, but without manually moving the window old size (to which the print preview was sized to) is retained and has ugly artifact.
What can I do? Basically if I could trap the moment when print preview is closed, I could use following trick:
// Trigger the WM_MINMAXINFO message:
CFrameWnd *pFrame = GetParentFrame();
RECT rectWindow;
pFrame->GetWindowRect(&rectWindow);
pFrame->MoveWindow(&rectWindow);
But I don't know how to trap print-preview closure.
What I'm trying to accomplish seems quite standard: who would want to have frame window resized bigger than view's logical size (set by SetScrollSizes())? So there should be some more natural solution maybe?
In your CMyFckinView, handle a message that is reliably sent when the print preview is closed and then post a user message to the mainframe which will trigger your "force minmax" code. Perhaps WM_FOCUS or WM_ACTIVATE?
Im creating a drop down menu and i want to know if there is anyway to implement the following:
I need to keep the sub-menu open for like 1 sec if the user moves the mouse away from the tab he selected. Much likely like in current intel web page www.intel.com , here u hover over menu, but if u take the mouse away from the tab or the sub-menu is opens it takes a few to hide the sub menu.
Im using .mouseover from jquery to show the menu (a div) but i cant find a way to make it stay for a few moments.
Thanks in advance
This may be of service
What is the JavaScript version of sleep()?
If you want to do something in the interim setTimeout() takes the arguments as shown where continue execution is another subroutine. If you just want this one tab to work this way have mouseover call doStuff and set a boolean (e.g. mouseStillIn) to TRUE. When the mouse exits set this boolean to FALSE, call a recursive function everytime mouseStillIn is TRUE.
e.g.
var mouseStillIn : boolean = false;
function MouseIn()
{
mouseStillIn=true;
CheckMouse();
}
function CheckMouse()
{
if(mouseStillIn)
{
setTimeout(CheckMouse, 1000);
}
}
function MouseOut()
{
mouseStillIn=false;
}