The combo box control uses most of the same messages as the entry field control and the list box control. In particular, the following messages are supported to achieve the functions of a combo box. These messages are explained in detail in the entry field control window messages and the list box control window messages sections.

WM_SETWINDOWPARAMS (in Entry Fields)

To set the text of the entry field.
WM_QUERYWINDOWPARAMS (in Entry Fields)
To obtain the text of the entry field.
LM_QUERYITEMCOUNT
To obtain the count of items in the list box control.
LM_INSERTITEM
To insert an item into the list box control.
LM_SETTOPINDEX
To scroll the list box control so that the specified item is at the top.
LM_QUERYTOPINDEX
To obtain the index of the item at the top of the list box control.
LM_DELETEITEM
To delete an item from the list box control. If necessary, this also changes the content of the entry field to the item at the top of the list box control.
LM_SELECTITEM
To select a specified item in the list box control. Also, this changes the content of the entry field to the item at the top of the list box control and, if the list box control is not visible, causes the list box control to 'dropdown' below the entry field control.
LM_QUERYSELECTION
To obtain the current selection in the list box control.
LM_SETITEMTEXT
To change the text of an item in the list box control. If necessary, this also changes the content of the entry field control.
LM_QUERYITEMTEXT
To obtain the text of an item in the list box control.
LM_QUERYITEMTEXTLENGTH
To obtain the length of the text of an item in the list box control.
LM_SEARCHSTRING
To obtain the index of an item in the list box control containing a specified string.
LM_DELETEALL
To delete all the items in the list box control.
WM_ENABLE
To enable the combo box control to respond to input.
EM_QUERYFIRSTCHAR
To obtain the character displayed at the left edge of the entry field control.
EM_SETFIRSTCHAR
To scroll the entry field control so that the specified character is displayed at the left edge of the entry field control.
EM_QUERYCHANGED
To obtain the changes to the entry field control.
EM_QUERYSEL
To obtain the current selection of the entry field control.
EM_SETSEL
To set the current selection of the entry field control.
EM_SETTEXTLIMIT
To set the maximum number of characters to be contained in the entry field control.
EM_CUT
To place the contents of the selection of the entry field control into the clipboard and then delete those contents from the entry field control.
EM_PASTE
To place the contents of the clipboard into the entry field control.
EM_COPY
To place the contents of the selection of the entry field control into the clipboard.
EM_CLEAR
To clear the current selection of the entry field control.

---

[Back] [Next]