MEASUREITEMSTRUCT

MEASUREITEMSTRUCT

The MEASUREITEMSTRUCT structure informs Windows of the dimensions of an owner-drawn control or menu item. This allows Windows to process user interaction with the control correctly.

typedef struct tagMEASUREITEMSTRUCT { // mis

UINT CtlType; // type of control

UINT CtlID; // combo box, list box, or button identifier

UINT itemID; // menu item, variable-height list box, or combo box identifier

UINT itemWidth; // width of menu item, in pixels

UINT itemHeight; // height of single item in list box menu, in pixels

DWORD itemData; // application-defined 32-bit value

} MEASUREITEMSTRUCT;

Members

CtlType

Specifies the control type. This member can be one of the following values:

Value	Meaning
ODT_BUTTON	Owner-drawn button
ODT_COMBOBOX	Owner-drawn combo box
ODT_LISTBOX	Owner-drawn list box
ODT_LISTVIEW	Owner-draw listview control
ODT_MENU	Owner-drawn menu

CtlID

Specifies the identifier of the combo box, list box, or button. This member is not used for a menu.

itemID

Specifies the identifier for a menu item or the position of a list box or combo box item. This value is specified for a list box only if it has the LBS_OWNERDRAWVARIABLE style; this value is specified for a combo box only if it has the CBS_OWNERDRAWVARIABLE style.

itemWidth

Specifies the width, in pixels, of a menu item. Before returning from the message, the owner of the owner-drawn menu item must fill this member.

itemHeight

Specifies the height, in pixels, of an individual item in a list box or a menu. Before returning from the message, the owner of the owner-drawn combo box, list box, or menu item must fill out this member.

itemData

Specifies the application-defined 32-bit value associated with the menu item. For a control, this member specifies the value last assigned to the list box or combo box by the LB_SETITEMDATA or CB_SETITEMDATA message. If the list box or combo box has the LB_HASSTRINGS or CB_HASSTRINGS style, this value is initially zero. Otherwise, this value is initially the value passed to the list box or combo box in the lParam parameter of one of the following messages:

CB_ADDSTRING
CB_INSERTSTRING
LB_ADDSTRING
LB_INSERTSTRING

Remarks

The owner window of an owner-drawn control receives a pointer to the MEASUREITEMSTRUCT structure as the lParam parameter of a WM_MEASUREITEM message. The owner-drawn control sends this message to its owner window when the control is created. The owner then fills in the appropriate members in the structure for the control and returns. This structure is common to all owner-drawn controls.

If an application does not fill the appropriate members of MEASUREITEMSTRUCT, the control or menu item may not be drawn properly.