accessing parent variables from dialog mfc??

bimgot

i'm quite new to mfc/c++ and i'm trying to create a really simple dialog box which controls the master volume of a simple form view application.. i've created the dialog and the variables to control the master volume in the form class (i've tested by creating a control in the form view and this works fine) but when i try to access and alter the form parameter from the dialog using a pointer and GetParent() during OnTimer(), it just does nothing... am i missing something? thanks in advance

led mike

bimgot wrote:

am i missing something?

Just a WAG: UpdateData()

led mike

bimgot

have tried UpdateData() does the dialog class require any settings in order to access the parent variables? i've even tried just very simple variable tests in OnTimer in the dialog class and it seems to have no effect on them.. is OnTimer even the right function to be using? i use it in the main form for a simelar process so i figured it would be but perhaps its different for dialogs?

David Crow

bimgot wrote:

...it just does nothing...

Which means "nothing" without any supporting data. Does GetParent() return the correct parent address? How about a snippet of code that shows what does not work?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

bimgot

OnTimer in the dialog class: void CDlg::OnTimer(UINT_PTR nIDEvent) { CDialog::OnTimer(nIDEvent); dlg_level = dlg_sldr.GetPos(); CformView* form = (CformView*) GetParent(); form->form_level = dlg_level; form->UpdateData(TRUE); UpdateData(TRUE); } then from form view class: void CformView::OnViewDlg() { CDlg dialog; dialog.dlg_level = form_sldr.GetPos(); dialog.DoModal(); } hope this makes sense

JudyL_MD

UpdateData (TRUE) puts the values currently in the controls into the variables. You need to call UpdateData (FALSE) to move the variable values into the screen controls. Note that I have added a line. This is so that if you have other controls on the screen, you won't lose the values the user might have changed on the screen when you call UpdateData (FALSE).

void CDlg::OnTimer(UINT_PTR nIDEvent)
{
CDialog::OnTimer(nIDEvent);
dlg_level = dlg_sldr.GetPos();

CformView* form = (CformView*) GetParent();
UpdateData (TRUE);
form->form_level = dlg_level;
form->UpdateData(FALSE);

UpdateData(TRUE);
}

Judy

David Crow

JudyL_FL wrote:

UpdateData (TRUE) puts the values currently in the controls into the variables. You need to call UpdateData (FALSE) to move the variable values into the screen controls.

All the more reason why UpdateData() should rarely, if ever, be used.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

David Crow

How does this answer the question, "Does GetParent() return the correct parent address?"

void CDlg::OnTimer(UINT_PTR nIDEvent)
{
CDialog::OnTimer(nIDEvent);
dlg_level = dlg_sldr.GetPos();

CformView\* form = (CformView\*) GetParent();
// what is the value of 'form' here?
form->form\_level = dlg\_level;
form->UpdateData(TRUE);

UpdateData(TRUE);

}

void CformView::OnViewDlg()
{
CDlg dialog;
// what is the value of the 'this' pointer here?
dialog.dlg_level = form_sldr.GetPos();
dialog.DoModal();
}

Since CDlg is a modal dialog, I question whether this will even work, since messages sent to its parent will be blocked until DoModal() returns.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

bimgot

thanks very much, i understand UpdateData a bit more now, i think i must have initialised something incorrectly, this still doesnt seem to update the values in the form.. the pointer to the main form is working correctly, if i call something like form->CloseWindow() during OnTimer it works.. i'm using OnTimer() in the main form to actually call the function which sets the volume: void CformView::OnTimer(UINT_PTR nIDEvent) { CFormView::OnTimer(nIDEvent); SetVolume(form_level); UpdateData(FALSE); } would this still get called during the life of the dialog or do i need to set the volume somewhere else? also is it possible some of the properties of the dialog could be effecting things?? really racking my brain here.. thanks

bimgot

void CDlg::OnTimer(UINT_PTR nIDEvent) { CDialog::OnTimer(nIDEvent); dlg_level = dlg_sldr.GetPos(); CformView* form = (CformView*) GetParent(); // form points to the main form class correctly form->form_level = dlg_level; form->UpdateData(TRUE); UpdateData(TRUE); } void CformView::OnViewDlg() { CDlg dialog; // this points to the main form class as this is a member function dialog.dlg_level = form_sldr.GetPos(); dialog.DoModal(); } i did consider a modal dialog as bieng inappropriate for this but was unsure as i dont actually need to control the main window whilst the dialog is open, i just want to update some variables..

David Crow

bimgot wrote:

...i dont actually need to control the main window whilst the dialog is open, i just want to update some variables..

So why call UpdateData() then?

void CformView::OnViewDlg()
{
CDlg dialog;
dialog.dlg_level = form_sldr.GetPos();
dialog.DoModal();
// is form_level correct at this point?
}

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

bimgot

i dont believe it is no.. if i call void CformView::OnViewDlg() { CDlg dialog; dialog.dlg_level = form_sldr.GetPos(); dialog.DoModal(); form_sldr.SetPos(dialog.dlg_level); } this updates the variable when the dialog is closed, but i want to update the variable as the dialog is running.. trying the same but with: form_sldr.SetPos(form_level); after DoModal(); doesnt update the control in the same way..

David Crow

bimgot wrote:

i want to update the variable as the dialog is running

Which contradicts your earlier statement of, "...i dont actually need to control the main window whilst the dialog is open." :confused:

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

bimgot

sorry i was unclear here, i need to control the window in that i want to be able to update its variables, but i dont need to physically control or move the window..