[VC ++] Why does the ComboBox getcursel () variable change the cstring variable associated with it not get-1?

When ComboBox is input directly, the matched list items are automatically selected, and setwindowtext does not
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// Get the ComboBox text
Void getcomboboxstring (hwnd hwndctrl, cstring & value)
{
// Just get current edit item text (or drop list static)
Int nlen =: getwindowtextlength (hwndctrl );
If (nlen> 0)
{
// Get known length
: Getwindowtext (hwndctrl, value. getbuffersetlength (nlen), nlen + 1 );
}
Else
{
// For drop lists getwindowtextlength does not work-assume
// Max of 255 characters
: Getwindowtext (hwndctrl, value. getbuffer (255), 255 + 1 );
}
Value. releasebuffer ();
}
 
// Set ComboBox text
Void setcomboboxstring (hwnd hwndctrl, const cstring & value)
{
// Set current selection based on model string
Outputdebugstring ("setcomboboxstring:" + value );
If (: sendmessage (hwndctrl, cb_selectstring, (wparam)-1,
(Lparam) (lpctstr) value) = cb_err)
{
// Just set the edit text (will be ignored if dropdownlist)
Afxsetwindowtext (hwndctrl, value );
}
}
 
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Your combox can be edited. The default value is-1. Enter a D. When getcursel is used, it is also-1, because you have not selected any.
 
Cstring strinput;
Int NSEL = m_combobox.getcursel ();
M_combox.getlbtext (NSEL, strinput );
In this way, you can get the selected one. In strinput
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If (m_combox.selectstring (m_combo) = cb_err)
{
This string m_combo does not exist in the original list.
}
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ComboBox does not provide the "Enter content in edit" function. After you press enter, the content will be automatically added to the ComboBox drop-down list.
 
This function must be implemented by yourself...
 
In pretranslatemessage, the carriage return is detected, that is, the content in ComboBox is added to the list.
 
Bool ctest6dlg: pretranslatemessage (MSG * PMSG)
{
Cstring STR;
If (PMSG-> message = wm_keydown)
{
Switch (PMSG-> wparam)
{
Case vk_return:
Cedit * pedit = (cedit *) m_combo1.getwindow (gw_child );
If (PMSG-> hwnd = pedit-> m_hwnd)
{
M_combo1.getwindowtext (STR );
M_combo1.addstring (STR );
}
Return true;
}
}
Return cdialog: pretranslatemessage (PMSG );
}