MEASUREITEMSTRUCT

3.0

typedef struct tagMEASUREITEMSTRUCT {   /* mi */
    UINT   CtlType;
    UINT   CtlID;
    UINT   itemID;
    UINT   itemWidth;
    UINT   itemHeight;
    DWORD  itemData;
} MEASUREITEMSTRUCT;

The MEASUREITEMSTRUCT structure informs Windows of the dimensions of an owner-drawn control. This allows Windows to process user interaction with the control correctly. The owner of an owner-drawn control receives a pointer to this structure as the lParam parameter of an 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.

Members

CtlType

Specifies the control type. The values for control types are as follows:

CtlID

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

itemID

Specifies the menu-item identifier for a menu or the list-box item identifier for a variable-height combo box or list box. This member is not used for a fixed-height combo box or list box or for a button.

itemWidth

Specifies the width of a menu item. The owner of the owner-drawn menu item must fill this member before returning from the message.

itemHeight

Specifies the height 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. The maximum height of a list box item is 255.

itemData

Contains the value that was passed to the combo box or list box in the lParam parameter of one of the following messages:

CB_ADDSTRING CB_INSERTSTRING LB_ADDSTRING LB_INSERTSTRING

Comments

Failure to fill out the proper members in the MEASUREITEMSTRUCT structure will cause improper operation of the control.