Combo Box (Windows Controls)

This section contains information about the programming elements used with combo boxes. A combo box is a unique type of control, defined by the COMBOBOX class, that combines much of the functionality of a list box and an edit control.

Overviews

Topic	Contents
About Combo Boxes	This section discusses the different kinds of combo boxes.
Combo Box Features	This document discusses features of the combo box.
Using Combo Boxes	The code examples in this section demonstrate how to perform tasks associated with combo boxes.

Functions

Topic	Contents
DlgDirListComboBox	Replaces the contents of a combo box with the names of the subdirectories and files in a specified directory. You can filter the list of names by specifying a set of file attributes. The list of names can include mapped drive letters.
DlgDirSelectComboBoxEx	Retrieves the current selection from a combo box filled by using the DlgDirListComboBox function. The selection is interpreted as a drive letter, a file, or a directory name.
GetComboBoxInfo	Retrieves information about the specified combo box.

Macros

Topic	Contents
ComboBox_AddItemData	Adds item data to the list in a combo box at the specified location. You can use this macro or send the CB_ADDSTRING message explicitly.
ComboBox_AddString	Adds a string to a list in a combo box. If the combo box does not have the CBS_SORT style, the string is added to the end of the list. Otherwise, the string is inserted into the list and the list is sorted. You can use this macro or send the CB_ADDSTRING message explicitly.
ComboBox_DeleteString	Deletes the item at the specified location in a list in a combo box. You can use this macro or send the CB_DELETESTRING message explicitly.
ComboBox_Dir	Adds names to the list displayed by a combo box. The macro adds the names of directories and files that match a specified string and set of file attributes. It can also add mapped drive letters to the list in a combo box. You can use this macro or send the CB_DIR message explicitly.
ComboBox_Enable	Enables or disables a combo box control.
ComboBox_FindItemData	Finds the first item in a combo box list that has the specified item data. You can use this macro or send the CB_FINDSTRING message explicitly.
ComboBox_FindString	Finds the first string in a combo box list that begins with the specified string. You can use this macro or send the CB_FINDSTRING message explicitly.
ComboBox_FindStringExact	Finds the first string in a combo box list that exactly matches the specified string, except that the search is not case sensitive. You can use this macro or send the CB_FINDSTRINGEXACT message explicitly.
ComboBox_GetCount	Gets the number of items in the list box of a combo box. You can use this macro or send the CB_GETCOUNT message explicitly.
ComboBox_GetCueBannerText	Gets the cue banner text displayed in the edit control of a combo box. Use this macro or send the CB_GETCUEBANNER message explicitly.
ComboBox_GetCurSel	Gets the index of the currently selected item in a combo box. You can use this macro or send the CB_GETCURSEL message explicitly.
ComboBox_GetDroppedControlRect	Retrieves the screen coordinates of a combo box in its dropped-down state. You can use this macro or send the CB_GETDROPPEDCONTROLRECT message explicitly.
ComboBox_GetDroppedState	Ascertains whether the drop list in a combo box control is visible. You can use this macro or send the CB_GETDROPPEDSTATE message explicitly.
ComboBox_GetExtendedUI	Ascertains whether a combo box is using the default user interface (UI) or the extended UI. You can use this macro or send the CB_GETEXTENDEDUI message explicitly.
ComboBox_GetItemData	Gets the application-defined value associated with the specified list item in a combo box. You can use this macro or send the CB_GETITEMDATA message explicitly.
ComboBox_GetItemHeight	Retrieves the height of list items in a combo box. You can use this macro or send the CB_GETITEMHEIGHT message explicitly.
ComboBox_GetLBText	Gets a string from a list in a combo box. You can use this macro or send the CB_GETLBTEXT message explicitly.
ComboBox_GetLBTextLen	Gets the length of a string in the list in a combo box. You can use this macro or send the CB_GETLBTEXTLEN message explicitly.
ComboBox_GetMinVisible	Gets the minimum number of visible items in the drop-down list of a combo box.
ComboBox_GetText	Retrieves the text from a combo box control.
ComboBox_GetTextLength	Gets the number of characters in the text of a combo box.
ComboBox_InsertItemData	Inserts item data in a list in a combo box at the specified location. You can use this macro or send the CB_INSERTSTRING message explicitly.
ComboBox_InsertString	Adds a string to a list in a combo box at the specified location. You can use this macro or send the CB_INSERTSTRING message explicitly.
ComboBox_LimitText	Limits the length of the text the user may type into the edit control of a combo box. You can use this macro or send the CB_LIMITTEXT message explicitly.
ComboBox_ResetContent	Removes all items from the list box and edit control of a combo box. You can use this macro or send the CB_RESETCONTENT message explicitly.
ComboBox_SelectItemData	Searches a list in a combo box for an item that has the specified item data. If a matching item is found, the item is selected. You can use this macro or send the CB_SELECTSTRING message explicitly.
ComboBox_SelectString	Searches a list in a combo box for an item that begins with the characters in a specified string. If a matching item is found, the item is selected. You can use this macro or send the CB_SELECTSTRING message explicitly.
ComboBox_SetCueBannerText	Sets the cue banner text that is displayed for the edit control of a combo box.
ComboBox_SetCurSel	Sets the currently selected item in a combo box. You can use this macro or send the CB_SETCURSEL message explicitly.
ComboBox_SetExtendedUI	Selects either the default user interface (UI) or the extended UI for a combo box that has the CBS_DROPDOWN or CBS_DROPDOWNLIST style. You can use this macro or send the CB_SETEXTENDEDUI message explicitly.
ComboBox_SetItemData	Sets the application-defined value associated with the specified list item in a combo box. You can use this macro or send the CB_SETITEMDATA message explicitly.
ComboBox_SetItemHeight	Sets the height of list items or the selection field in a combo box. You can use this macro or send the CB_SETITEMHEIGHT message explicitly.
ComboBox_SetMinVisible	Sets the minimum number of visible items in the drop-down list of a combo box.
ComboBox_SetText	Sets the text of a combo box.
ComboBox_ShowDropdown	Shows or hides the list in a combo box. You can use this macro or send the CB_SHOWDROPDOWN message explicitly.

Messages

Topic	Contents
CB_ADDSTRING	Adds a string to the list box of a combo box. If the combo box does not have the CBS_SORT style, the string is added to the end of the list. Otherwise, the string is inserted into the list, and the list is sorted.
CB_DELETESTRING	Deletes a string in the list box of a combo box.
CB_DIR	Adds names to the list displayed by the combo box. The message adds the names of directories and files that match a specified string and set of file attributes. CB_DIR can also add mapped drive letters to the list.
CB_FINDSTRING	Searches the list box of a combo box for an item beginning with the characters in a specified string.
CB_FINDSTRINGEXACT	Finds the first list box string in a combo box that matches the string specified in the lParam parameter.
CB_GETCOMBOBOXINFO	Gets information about the specified combo box.
CB_GETCOUNT	Gets the number of items in the list box of a combo box.
CB_GETCUEBANNER	Gets the cue banner text displayed in the edit control of a combo box. Send this message explicitly or by using the ComboBox_GetCueBannerText macro.
CB_GETCURSEL	An application sends a CB_GETCURSEL message to retrieve the index of the currently selected item, if any, in the list box of a combo box.
CB_GETDROPPEDCONTROLRECT	An application sends a CB_GETDROPPEDCONTROLRECT message to retrieve the screen coordinates of a combo box in its dropped-down state.
CB_GETDROPPEDSTATE	Determines whether the list box of a combo box is dropped down.
CB_GETDROPPEDWIDTH	Gets the minimum allowable width, in pixels, of the list box of a combo box with the CBS_DROPDOWN or CBS_DROPDOWNLIST style.
CB_GETEDITSEL	Gets the starting and ending character positions of the current selection in the edit control of a combo box.
CB_GETEXTENDEDUI	Determines whether a combo box has the default user interface or the extended user interface.
CB_GETHORIZONTALEXTENT	Gets the width, in pixels, that the list box can be scrolled horizontally (the scrollable width). This is applicable only if the list box has a horizontal scroll bar.
CB_GETITEMDATA	An application sends a CB_GETITEMDATA message to a combo box to retrieve the application-supplied value associated with the specified item in the combo box.
CB_GETITEMHEIGHT	Determines the height of list items or the selection field in a combo box.
CB_GETLBTEXT	Gets a string from the list of a combo box.
CB_GETLBTEXTLEN	Gets the length, in characters, of a string in the list of a combo box.
CB_GETLOCALE	Gets the current locale of the combo box. The locale is used to determine the correct sorting order of displayed text for combo boxes with the CBS_SORT style and text added by using the CB_ADDSTRING message.
CB_GETMINVISIBLE	Gets the minimum number of visible items in the drop-down list of a combo box.
CB_GETTOPINDEX	An application sends the CB_GETTOPINDEX message to retrieve the zero-based index of the first visible item in the list box portion of a combo box. Initially, the item with index 0 is at the top of the list box, but if the list box contents have been scrolled, another item may be at the top.
CB_INITSTORAGE	An application sends the CB_INITSTORAGE message before adding a large number of items to the list box portion of a combo box. This message allocates memory for storing list box items.
CB_INSERTSTRING	Inserts a string or item data into the list of a combo box. Unlike the CB_ADDSTRING message, the CB_INSERTSTRING message does not cause a list with the CBS_SORT style to be sorted.
CB_LIMITTEXT	Limits the length of the text the user may type into the edit control of a combo box.
CB_RESETCONTENT	Removes all items from the list box and edit control of a combo box.
CB_SELECTSTRING	Searches the list of a combo box for an item that begins with the characters in a specified string. If a matching item is found, it is selected and copied to the edit control.
CB_SETCUEBANNER	Sets the cue banner text that is displayed for the edit control of a combo box.
CB_SETCURSEL	An application sends a CB_SETCURSEL message to select a string in the list of a combo box. If necessary, the list scrolls the string into view. The text in the edit control of the combo box changes to reflect the new selection, and any previous selection in the list is removed.
CB_SETDROPPEDWIDTH	An application sends the CB_SETDROPPEDWIDTH message to set the maximum allowable width, in pixels, of the list box of a combo box with the CBS_DROPDOWN or CBS_DROPDOWNLIST style.
CB_SETEDITSEL	An application sends a CB_SETEDITSEL message to select characters in the edit control of a combo box.
CB_SETEXTENDEDUI	An application sends a CB_SETEXTENDEDUI message to select either the default UI or the extended UI for a combo box that has the CBS_DROPDOWN or CBS_DROPDOWNLIST style.
CB_SETHORIZONTALEXTENT	An application sends the CB_SETHORIZONTALEXTENT message to set the width, in pixels, by which a list box can be scrolled horizontally (the scrollable width). If the width of the list box is smaller than this value, the horizontal scroll bar horizontally scrolls items in the list box. If the width of the list box is equal to or greater than this value, the horizontal scroll bar is hidden or, if the combo box has the CBS_DISABLENOSCROLL style, disabled.
CB_SETITEMDATA	An application sends a CB_SETITEMDATA message to set the value associated with the specified item in a combo box.
CB_SETITEMHEIGHT	An application sends a CB_SETITEMHEIGHT message to set the height of list items or the selection field in a combo box.
CB_SETLOCALE	An application sends a CB_SETLOCALE message to set the current locale of the combo box. If the combo box has the CBS_SORT style and strings are added using CB_ADDSTRING, the locale of a combo box affects how list items are sorted.
CB_SETMINVISIBLE	An application sends a CB_SETMINVISIBLE message to set the minimum number of visible items in the drop-down list of a combo box.
CB_SETTOPINDEX	An application sends the CB_SETTOPINDEX message to ensure that a particular item is visible in the list box of a combo box. The system scrolls the list box contents so that either the specified item appears at the top of the list box or the maximum scroll range has been reached.
CB_SHOWDROPDOWN	An application sends a CB_SHOWDROPDOWN message to show or hide the list box of a combo box that has the CBS_DROPDOWN or CBS_DROPDOWNLIST style.

Notifications

Topic	Contents
CBN_CLOSEUP	The CBN_CLOSEUP notification code is sent when the list box of a combo box has been closed. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_DBLCLK	The CBN_DBLCLK notification code is sent when the user double-clicks a string in the list box of a combo box. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_DROPDOWN	The CBN_DROPDOWN notification code is sent when the list box of a combo box is about to be made visible. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_EDITCHANGE	The CBN_EDITCHANGE notification code is sent after the user has taken an action that may have altered the text in the edit control portion of a combo box. Unlike the CBN_EDITUPDATE notification code, this notification code is sent after the system updates the screen. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_EDITUPDATE	The CBN_EDITUPDATE notification code is sent when the edit control portion of a combo box is about to display altered text. This notification code is sent after the control has formatted the text, but before it displays the text. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_ERRSPACE	The CBN_ERRSPACE notification code is sent when a combo box cannot allocate enough memory to meet a specific request. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_KILLFOCUS	The CBN_KILLFOCUS notification code is sent when a combo box loses the keyboard focus. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_SELCHANGE	The CBN_SELCHANGE notification code is sent when the user changes the current selection in the list box of a combo box. The user can change the selection by clicking in the list box or by using the arrow keys. The parent window of the combo box receives this notification in the form of a WM_COMMAND message with CBN_SELCHANGE in the high-order word of the wParam parameter.
CBN_SELENDCANCEL	The CBN_SELENDCANCEL notification code is sent when the user selects an item, but then selects another control or closes the dialog box. It indicates the user's initial selection is to be ignored. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_SELENDOK	The CBN_SELENDOK notification code is sent when the user selects a list item, or selects an item and then closes the list. It indicates that the user's selection is to be processed. The parent window of the combo box receives this notification code through the WM_COMMAND message.
CBN_SETFOCUS	The CBN_SETFOCUS notification code is sent when a combo box receives the keyboard focus. The parent window of the combo box receives this notification code through the WM_COMMAND message.
WM_COMPAREITEM	The system sends the WM_COMPAREITEM message to determine the relative position of a new item in the sorted list of an owner-drawn combo box or list box. Whenever the application adds a new item, the system sends this message to the owner of a combo box or list box created with the CBS_SORT or LBS_SORT style.
WM_DRAWITEM	The WM_DRAWITEM message is sent to the parent window of an owner-drawn button, combo box, list box, or menu when a visual aspect of the button, combo box, list box, or menu has changed.
WM_MEASUREITEM	The WM_MEASUREITEM message is sent to the owner window of a combo box, list box, list-view control, or menu item when the control or menu is created.

Structures

Topic	Contents
COMBOBOXINFO	Contains combo box status information.
COMPAREITEMSTRUCT	Supplies the identifiers and application-supplied data for two items in a sorted, owner-drawn list box or combo box.
DRAWITEMSTRUCT	Provides necessary information the owner window to determine how to paint an owner-drawn control or menu item. The owner window of the owner-drawn control or menu item receives a pointer to this structure as the lParam parameter of the WM_DRAWITEM message.
MEASUREITEMSTRUCT	Informs the system of the dimensions of an owner-drawn control or menu item. This allows the system to process user interaction with the control correctly.

Constants

Topic	Contents
Combo Box Styles	To create a combo box using the CreateWindow or CreateWindowEx function, specify the COMBOBOX class, appropriate window style constants, and a combination of the following combo box styles.