7.6.2 Control Data

A dialog box resource contains data for each control in a given dialog box. This data contains the coordinates of the upper-left corner of the control, the dimensions of the control, a control identifier, and so on. A ControlData structure has the following form:

struct ControlData {
    WORD  x;
    WORD  y;
    WORD  cx;
    WORD  cy;
    WORD  wID;
    DWORD lStyle;
    union
    {
        BYTE class;     /* if (class & 0x80) */
        char szClass[]; /* otherwise         */
    } ClassID;
    szText;
};

Following are the members in the ControlData structure:

x

Specifies the x-coordinate of the upper-left corner of the control.

y

Specifies the y-coordinate of the upper-left corner of the control.

cx

Specifies the width of the control, in horizontal dialog box units. For a definition of these units, see the DialogBoxHeader structure in the preceding section.

cy

Specifies the height of the control, in vertical dialog box units. For a definition of these units, see the DialogBoxHeader structure in the preceding section.

wID

Identifies the control.

lStyle

Specifies the control style. This member is a combination of the window-style flags that appear in the WINDOWS.H file.

ClassID

Specifies the class type. This member is either a single-byte value or a null-terminated string.

If this member is a byte value, it can be one of the following:

If this number is not a byte value, it takes the form described in the szClass member.

szClass

Identifies the class type. This member is a null-terminated string.

szText

Specifies the control text. This member is a null-terminated string.