CCombBox reinitialization problem
Michael S. Raymond -- nontech@iag.net
Tuesday, March 25, 1997
Environment: VC4.0, Win95
Ok,
I am writing an small, CPropertySheet/Page based application for
entering medical expenses into an Access database. There is nothing
really amazing/difficult about the application - except for two minor
but troubling points.
1) The CPropertySheet is operating in a modal state - but I have
suppressed the OK, Cancel, Apply, and Help buttons and replaced them
with Save, Clear, and Done. I have carefully set the tab order so a
user can key in data on the page and press Enter to save it. Everything
(including the focus) seems to work fine. However, if the user clicks
on one of my buttons, the button visually depresses - but when the user
presses Enter with a button selected, the button activity takes place
but the button does not depress.
NOTE: I have overridden the default IDOK() to prevent the modal
CPropertySheet from closing. In this function, I tried a variety of
CButton and CWnd functions for setting control/window state - but
nothing had any effect on the button(s).
The buttons are all members of the CPropertySheet class and they are
created dynamically on the page. I am sure it is a messaging thing -
but I am unable to locate an example that helps clear up my problem.
2) The 'Clear' button (described above) sends a message to the
CPropertyPage-derived class for the currently selected page. The
message instructs the page to clear all selections/values from the
fields. While all of my other (CEdit) fields clear just fine, two
CComboBox controls do not clear. I have tried using CComboBox::Clear(),
CComboBox::Reset(), SelectString() [after setting up a blank entry in
the box], and even CWnd.SetWindowText with no luck. The following code
is an excerpt from the CPropertyPage-related function for clearing the
fields:
LRESULT CExpensePage::OnClear(WPARAM wParam, LPARAM lParam)
{
// expense page
m_CategoryCombo.Clear();
m_PatientNameCombo.Clear();
m_Concluded = FALSE;
m_TransactionAmount = 0;
m_PaymentAmount = 0;
m_TransDate = '\0';
UpdateData(FALSE); // don't know if this is necessary
return lParam;
}
Seems like the Clear() function should do the trick. Any suggestions?
Thanks in advance for your help
Michael S. Raymond
nontech@iag.net
tiger@flynet.de
Friday, March 28, 1997
[Mini-digest: 3 responses]
You should call Clear() after UpdateData(FALSE). If you call
UpdateData after you've called Clear() and there's a CString Member
associated to your ComboBox, UpdateData will put the string back into
the edit-section of your ComboBox.
Hope this helps.
///////////////////////////////////////
// //
// Frank Leuenberger //
// tiger@flynet.de //
// //
///////////////////////////////////////
-----From: "Greg Tighe"
> 2) The 'Clear' button (described above) sends a message to the
> CPropertyPage-derived class for the currently selected page. The
> message instructs the page to clear all selections/values from the
> fields. While all of my other (CEdit) fields clear just fine, two
> CComboBox controls do not clear. I have tried using CComboBox::Clear(),
> CComboBox::Reset(), SelectString() [after setting up a blank entry in
> the box], and even CWnd.SetWindowText with no luck. The following code
> is an excerpt from the CPropertyPage-related function for clearing the
> fields:
>
> Seems like the Clear() function should do the trick. Any suggestions?
>
CComboBox::Clear() clears (deletes) any currently selected text
*within the edit control* of a combobox. It's like selecting some
text in a text editing control and then hitting the 'Delete' key. If
all the text in the edit control attached to your combobox was
selected when you invoked CComboBox::Clear() then the text would
disappear.
Seems like what you want to call is CComboBox::SetCurSel (-1).
According to the online doco:
CComboBox::SetCurSel
int SetCurSel( int nSelect );
/***********************************************/
Return Value
The zero-based index of the item selected if the message is
successful. The return value is CB_ERR if nSelect is greater than the
number of items in the list or if nSelect is set to =961, which clears
the selection.
Parameters
nSelect=A0=A0=A0Specifies the zero-based index of the string to select. If
=961, any current selection in the list box is removed and the edit
control is cleared.
/*********************************************/
-Greg Tighe
Applied Intelligent Systems, Inc.
Ann Arbor, MI
gdt@aisinc.com
-----From: "Dalmer Junior"
----------
> From: Michael S. Raymond
> To: mfc-l@netcom.com
> Subject: CCombBox reinitialization problem
> Date: Tuesday, March 25, 1997 11:46 PM
>
> Environment: VC4.0, Win95
>
> 2) The 'Clear' button (described above) sends a message to the
> CPropertyPage-derived class for the currently selected page. The
> message instructs the page to clear all selections/values from the
> fields. While all of my other (CEdit) fields clear just fine, two
> CComboBox controls do not clear. I have tried using CComboBox::Clear(),
> CComboBox::Reset(), SelectString() [after setting up a blank entry in
> the box], and even CWnd.SetWindowText with no luck. The following code
> is an excerpt from the CPropertyPage-related function for clearing the
> fields:
>
> LRESULT CExpensePage::OnClear(WPARAM wParam, LPARAM lParam)
> {
> // expense page
> m_CategoryCombo.Clear();
> m_PatientNameCombo.Clear();
> m_Concluded = FALSE;
> m_TransactionAmount = 0;
> m_PaymentAmount = 0;
> m_TransDate = '\0';
> UpdateData(FALSE); // don't know if this is necessary
>
> return lParam;
> }
>
> Seems like the Clear() function should do the trick. Any suggestions?
>
you should use the member function SetCurSel( -1 ). The -1 says to the
Combo that any current selection in the list box is to be removed and the
edit control cleared.
I hope help you
(:P
[]s,
--
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