Show modelless dialog initially hidden - c++

I have modelless child dialog. In resource properties Visible flag is set as true.(As per my requirement in resource properties visible flag should be true).
I want to programmatically hide the dialog while initially displaying.
I overrided the presubclasswindow and removed the WS_VISIBLE flag using below code but the dialog is not getting hidden.
void CAddressChildDlg::PreSubclassWindow()
{
CWnd::PreSubclassWindow();
if (::IsWindow(m_hWnd))
{
LONG lStyle = GetWindowLong(m_hWnd, GWL_STYLE);
lStyle &= ~WS_VISIBLE;
SetWindowLong(m_hWnd, GWL_STYLE, lStyle);
}
}
Please anyone help me to achieve my requirement

You can also override ON_WM_WINDOWPOSCHANGING
class CMyDialog : public CDialog
{
public:
bool m_override_showwindow;
//initialize somewhere ...
void OnWindowPosChanging(WINDOWPOS* wpos)
{
if (m_override_showwindow)
wpos->flags &= ~SWP_SHOWWINDOW;
CDialog::OnWindowPosChanging(wpos);
}
DECLARE_MESSAGE_MAP()
...
};
BEGIN_MESSAGE_MAP(CMyDialog, CDialog)
ON_WM_WINDOWPOSCHANGING()
...
END_MESSAGE_MAP()
Enable this override only when you don't want it to show the dialog. Make sure to disable the override otherwise dialog is never shown.
dlg.m_override_showwindow = true;
dlg.Create(...);
dlg.m_override_showwindow = false;
MessageBox(L"Test...");
dlg.ShowWindow(SW_SHOW);

You are not clear in what you want. Your title says you want to initially have the dialog hidden. then text in the question says you want it initially visible and then hidden. Which is it/
What do you mean by your requirement says that the dialog style has to be WS_VISIBLE. if you want to make it initially not visible, then don't include the flag.
For a modeless dialog, generally you create them on the heap whereas modal dialogs are typically created on the stack.
CYourDialog* pDlg = new CYourDialog(... and whatever arguments);
pDlg->Create(CYourDialog::IDD); // or whatever the ID is...
pDlg->ShowWindow(SW_NORMAL); // shows window if it was invisible...
pDlg->ShowWindow(SW_HIDE); // hides window if it was visible...

Related

Apply button in CDialog

I have a dialog in which after pressing button OK, the program uses the data in the dialog and draws a plot. I need to draw the plot without having to close the dialog as with IDOK, hence the apply button.
The code with drawing the dialog is,
INT_PTR val = dlg->DoModal();
if ( val == IDOK) {
//draw plot
}
The code of onOK and onApply
void DLg::OnOK() {
GetDataGrid();
CDialog::OnOK();
}
void DLg::OnBnClickedApply()
{
GetDataGrid();
}
How do I get DoModal() to return a value on onApply() without closing the dialog?
Any help would be appreciated.
A modal dialog can't return a value and leave the dialog open. You could either make your dialog non-modal, or post your main window a message from the OnBnClickedApply function that makes it draw the plot.
I tend to put drawing into a separate thread and would call it wherever needed. So you can either
(1) call the OnDrawPlot again in your Apply button
if ( val == IDOK) {
AfxBeginThread(...);//draw plot
}
void DLg::OnBnClickedApply()
{
AfxBeginThread(...);//draw plot
}
(2) send the return value back to the DoModal using EndDialog method
What parameters are there in EndDialog ?
An example can be found here.
Declare a variable in CDialog derived class preferably public. Then just at OnOK assign this variable to appropriate value. The caller would use it directly.
class Dlg : public CDialog
{
public:
int TheVariable;
...
};
Call site:
if(dlg.DoModal()==IDOK)
{
dlg.TheVariable; // Use the variable
}
However, if you need to draw on the dialog itself (and not to other window, which has launched the dialog), then don't call CDialog::OnOK or EndDialog in your OnOK override. In this case, you need to do painting in dialog itself.

Child Dialog - SetWindowTextA or SendMessageA crashes program - MFC

ERROR: afxwin2.inl line 165
My app is a dialog box with a few edit boxes. Once I click the button to evaluate the information entered I want to open a child dialog to display the results. I tried overloading DoModal() like this:
//in the child dialog
//.h
CResultsDlg::CResultsDlg(CParentDlg *parent);
virtual INT_PTR DoModal(float bmi);
//.cpp
CResultsDlg::CResultsDlg(CParentDlg *parent) : CDialogEx(CResultsDlg::IDD), _parent(parent)
{ //initializations }
INT_PTR CResultsDlg::DoModal(float bmi)
{
m_sBMI.Format("%f", bmi);
m_hBMI.SetWindowTextA(m_sBMI); //crashes !!!!!!!!!!
m_hBMI.SendMessageA(WM_SETTEXT, 0, (LPARAM)"15.11"); //crashes !!!!!!!!
// OnInitDialog(); //because this wasn't getting called at all
return CDialogEx::DoModal();
}
BOOL CResultsDlg::OnInitDialog()
{
CDialogEx::OnInitDialog();
// __super::OnInitDialog(); //no difference...
m_hBMI.SetWindowTextA("10.3"); //crashes !!!
return true; // return TRUE unless you set the focus to a control
}
//in the parent dialog
//.cpp
void CParentDlg::OnBnClickedCalculate()
{
CResultsDlg childResultsDlg = this;
childResultsDlg.DoModal(15.7);
}
m_hBMI is a handle to a static text control. I tested an edit box but it still crashed.
I understand that it probably has something to do with the controls not being created yet but I tried every way I know.
Using breakpoints, I confirmed that OnInitDialog does not get called at all unless I put it in the overloaded DoModal function. SetWindowText/SendMessage still crashes in OnInitDialog with the same ASSERT error.
If I remove all SetWindowText/SendMessage then the child window does come up modal like it should but the 'result' static text control is the same as the text I set it to in the dialog editor properties pane.
Thanks !!!!!
*MORE DETAILS*-----------
void CResultsDlg::DoDataExchange(CDataExchange* pDX) // DDX/DDV support
{
CDialogEx::DoDataExchange(pDX);
DDX_Text(pDX, IDC_BMI, m_fBMI);
DDV_MinMaxFloat(pDX, m_fBMI, 0, 100);
DDX_Control(pDX, IDC_BMI, m_hBMI);
}
The usual sequence when you start a dialog is:
You call CDialog::DoModal.
The dialog window gets created.
The child controls of the dialog get created.
OnInitDialog gets called.
CDialog::OnInitDialog calls DoDataExchange.
You have a DDX_Control call in your DoDataExchange method to map the child control to a member variable.
Notice that the member variables only get initialized at the end of that sequence. You're trying to use them way before, so you get a crash.
Store the value you need for initialization in a member variable and take care of it in DoDataExchange.

Changing static text in dialog box at runtime

I have created a dialog box and linked it to the menu item. In this case the menu item is Help -> Statistics. It all works. So when I run the program, click on the menu Help, then Statistics, a dialog box pops up.
I also have a static text box in the dialog box. How do you change the text of this static text box at runtime?
P.S: Though I have a dialog box up and running, I do not have the handle for the dialog box. If any of your solutions involve knowing the handle to the dialog box, please tell me how to retrieve it. Thanks.
EDIT:
class CStatisticsDlg : public CDialogEx
{
public:
CStatisticsDlg();
// Dialog Data
enum { IDD = IDD_STATISTICS };
protected:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support
// Implementation
protected:
DECLARE_MESSAGE_MAP()
public:
};
CStatisticsDlg::CStatisticsDlg() : CDialogEx(CStatisticsDlg::IDD)
{
}
void CStatisticsDlg::DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
}
BEGIN_MESSAGE_MAP(CStatisticsDlg, CDialogEx)
END_MESSAGE_MAP()
In Class Wizard, create a CString member variable for the label. Note: by default, labels don't have a custom id so you have to give it one like IDC_MY_LABEL.
Somewhere before showing the dialog call m_strMyLabel.SetWindowText("blah");
If you need to do it while the dialog is open you have to call UpdateData(FALSE)
Edit: if you don't want to create a member variable you can
**corrected - typing from memory....
// Find the label
// if called from within CStatusDlg class
CWnd *label = GetDlgItem(IDC_MY_LABEL);
label->SetWindowText("blah");
// If called from elsewhere
CStatusDlg dlg..... // create the dialog
CWnd *label = dlg.GetDlgItem(IDC_MY_LABEL);
label->SetWindowText("blah");

mfc access to formview item from dialog box

In my SDI application i need to get this behawiour. After I click on a button on the FormView, a CDialog opens. When I press the OK button on the CDialog, I call a function of the FormView. I don't want to close the CDialog. I try to do it with modeless dialog, but when i call formview function from dialog, i can't access to formview's control, like it's lost hwnd; the error is can't read memory of m_hwnd, the hwnd is ???.
This is my code:
Open modeless dialog:
CCampiDlg *m_pDialog = NULL;
HWND hCampi = NULL;
// Invoking the Dialog
m_pDialog = new CCampiDlg;
if (m_pDialog != NULL)
{
BOOL ret = m_pDialog->Create(m_pDialog->IDD, this);
if (!ret) //Create failed.
{
AfxMessageBox(_T("Error creating Dialog"));
}
m_pDialog->ShowWindow(SW_SHOW);
}
when i press the ok button in the dialog i do:
CEditorTxView pView;
box2 = (CEdit*)(GetDlgItem(IDC_CAMPI_BOX2));
box2->GetWindowTextW(campo);
pView.inserisciCampo(1, campo);
In inserisciCampo function in CEditorTxView (CFormView) i have to do operation with my control txtCtrl, but it's lost hwnd. The declaration of txtCtrl is in the CEditorTxView.h
CTx1 txtCtrl;
And initialize it in DoDataExchange function:
void CEditorTxView::DoDataExchange(CDataExchange* pDX)
{
CFormView::DoDataExchange(pDX);
DDX_Control(pDX, IDC_TX1, txtCtrl);
}
Someone can help me plz?
I can give you two answers here:
How to do what you are asking (get access to a control of the CFormView from a modeless dialog)
How to solve your underlying problem (communicate changes in a modeless dialog to the owner view)
For the first one, you have to declare a pointer to the view in the dialog class and initialize it in the constructor of the view:
class CCampiDlg : public CDialog
{
public:
CCampiDlg(CEditorTxView* pView, CWnd*pParent = NULL) // Change declaration to add pointer to view
: m_pView(pView)
{
}
// ... Whatever
private:
CEditorTxView* m_pView;
}
Now in your button handler:
CEdit* box2 = (CEdit*)(GetDlgItem(IDC_CAMPI_BOX2)); // Why not use a control variable?
box2->GetWindowTextW(campo);
m_pView->inserisciCampo(1, campo);
This should do what you are asking for. However, it is the wrong way to do it.
The problem with this approach is that the dialog knows way too much about its parent. It knows it is of type CEditorTxView and that it has a member called inserisciCampo, that takes a number and some text.
It shouldn't know that much. In fact, knowing anything about it, other than it is of type CView or even CWnd, is too much.
If the dialog knows about the view, you can't reuse the dialog with other views, and anytime the view changes its representation (what now is a textbox may be a combobox in the future, for example) the dialog must change accordingly.
The solution would be to send a message to the parent, explaining what's happened. Then the parent (the view) should know haw to handle that event. For example:
class CCampiDlg : public CDialog
{
public:
CCampiDlg(CWnd*pParent = NULL) {}
protected:
OnOk()
{
CString campo;
c_CampiBox2.GetWindowText(campo);
GetParent()->SendMessage(UWM_CAMPO2_SET, 0, (LPARAM)&campo);
}
}
In the view:
// It can be ON_REGISTERED_MESSAGE:
ON_MESSAGE(UWM_CAMPO2_SET, OnCampo2Set)
//...
LRESULT CEditorTxView::OnCampo2Set(WPARAM, LPARAM lParam)
{
CString* s = (CString*) lParam;
inserisciCampo(1, *campo);
return 0;
}
Now, you have decoupled the view and the dialog. The dialog knows nothing about the view. You can change its type, change the representation, even make it a dialog, and you don't have to change anything in the dialog. And if you need that same modeless dialog somewhere else, you just drop it there, create a message handler in the parent, and voilĂ !
For further explanations and better examples, check these articles:
Dialog and control design (Your case is explained in the section "Notifications to the environment")
Message management
On Ok button click the below code is running:
CEditorTxView pView;
box2 = (CEdit*)(GetDlgItem(IDC_CAMPI_BOX2));
box2->GetWindowTextW(campo);
pView.inserisciCampo(1, campo);
Note that, you are creating the new pView in stack and it does't attach with any window. You are not actually referring the view that already created and launched your dialog acting a parent. Revisit the above code and try the get the view:
Try the below code, if it is not working (Google it)
CFrameWnd * pFrame = (CFrameWnd *)(AfxGetApp()->m_pMainWnd);
CView * pView = pFrame->GetActiveView();

MFC: Creating modeless dialog box without displaying

I'm trying to create a simple modeless dialog box which I'm creating from my CWinApp derived InitInstance() function.
BOOL CMyApp::InitInstance()
{
...
m_pMyDialog = new CMyDialog();
m_pMyDialog->Create(CMyDialog::IDD);
...
retrun TRUE;
}
I've created the dialog template in the resource editor and the WS_VISIBLE bit is unset. My intention is to avoid showing the dialog until I explicitly call ShowWindow(SW_SHOW) but for some reason the call to Create displays the dialog.
I've tried to change the return value of OnInitDialog() to FALSE but that doesn't work.
I've even tried to call ModifyStyle() in case something else is setting the WS_VISIBLE bit.
int CMyDialog::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CDialog::OnCreate(lpCreateStruct) == -1)
return -1;
ModifyStyle(WS_VISIBLE, 0);
return 0;
}
That doesn't work either. In all cases, after I call Create the dialog is displayed which isn't how I've read it should work.
The problem was with AnimateWindow() which was causing the dialog to display prematurely.