Clearing the edit box in ccombobox

lctrncs

What does my OnSelChangeCombo function look like? It is rather simple: 1. Pointer to the Combobox with assert if NULL, 2. code to return index of selected item in listbox from control directed alpha listing (thank you Chris Losinger!), 3. dirtyflag check of record and associated commit if true, 4. call of the GotoRecord function.

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." Richard Feynman, Minority Report to the Official Report on the Space Shuttle Challenger Crash

David Crow

Ok, what I have here may help, or it may not since it is not entirely like what you have. I have a CRecordset-derived class that reads from the Employees table of the Northwind database. I have a dialog with a combobox (having the CBS_DROPDOWNLIST style) and listbox. Selecting an item from the combobox will add it to the listbox. The selection in the combobox is then cleared.

BOOL CMyDlg::OnInitDialog()
{
CDialog::OnInitDialog();

CDatabase db;
CSet rs(&db);

rs.Open();
while (! rs.IsEOF())
{
    m\_combo.AddString(rs.m\_LastName);
    rs.MoveNext();
}

rs.Close();

m\_combo.InsertString(0, "");
 
return TRUE;  // return TRUE  unless you set the focus to a control

}

void CMyDlg::OnSelchangeCombo1()
{
int nIndex = m_combo.GetCurSel();
CString strItem;
m_combo.GetLBText(nIndex, strItem);
m_list.AddString(strItem);

m\_combo.SetCurSel(0);

}

Is this close?

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

"Judge not by the eye but by the heart." - Native American Proverb

lctrncs

As I said, I have never tried to instantiate a class instance so that I can use the dot operator. I tried to instantiate it in a number of locations (mainframe.cpp main.c etc.) without success. So where should I instantiate my m_wndCombobox so that I can use the dot operator as you suggest m_combo.InsertStinrg(0,"") ? Why should the dot operator work when a pointer does not?

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." Richard Feynman, Minority Report to the Official Report on the Space Shuttle Challenger Crash

David Crow

lctrncs wrote:

So where should I instantiate my m_wndCombobox so that I can use the dot operator as you suggest

It should belong to the class that owns it (hence the m_ prefix). In my example, m_combo and m_list are both members of CMyDialog.

lctrncs wrote:

Why should the dot operator work when a pointer does not?

Pointer variables use ->, while non-pointer variables use a dot. In reality,

pointer->member

is equivalent to:

(*pointer).member

See here for more on the member-selection operator.

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

"Judge not by the eye but by the heart." - Native American Proverb

lctrncs

So I should right click on CDialog, choose Add Member Function and enter Ccombobox and m_combo to instantiate m_combo as a member CDialog?

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." Richard Feynman, Minority Report to the Official Report on the Space Shuttle Challenger Crash

David Crow

lctrncs wrote:

So I should right click on CDialog, choose Add Member Function and enter Ccombobox and m_combo to instantiate m_combo as a member CDialog?

No. Use ClassWizard (Ctrl+W) to associate a member variable with a control.

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

"Judge not by the eye but by the heart." - Native American Proverb

lctrncs

Well I got things running like you show here - the Class Wizard info was key - but it still does not clear the edit box in either dropdown or drop list mode - any other suggestions?

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." Richard Feynman, Minority Report to the Official Report on the Space Shuttle Challenger Crash

David Crow

If you can narrow this project down to just the relevant lines, you can e-mail it to me and I'll take a look.

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

"Judge not by the eye but by the heart." - Native American Proverb

lctrncs

Thank you. I spent some time with it this weekend and got it working. Thank You! Your assistance was of great service to me! Thank you again!

"For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." Richard Feynman, Minority Report to the Official Report on the Space Shuttle Challenger Crash

David Crow

Overall, what did you do to finally get it going?

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

"Judge not by the eye but by the heart." - Native American Proverb