Advanced MFC Programming

Chapter 7. Common Dialog Boxes
The standard dialog template can be copied from file “Commdlg.dll”. By default, all the controls in
this template will have a numerical ID. In order to make them easy to use, we can assign each ID a symbol,
this can be done by inputting a text ID and assigning the control’s original ID value to it in “ID” window of
the property sheet that is used for customizing the styles of a control. For example, when we open “Text
Properties” property sheet for control 720, its “ID” window shows “720”. We can change it to
“COLOR_BOX1=720”. By doing this, the control will have an ID symbol “COLOR_BOX1”, whose value is
720. In the sample, most of the controls are assigned ID symbols.
We can hide certain unnecessary controls by calling function CWnd::ShowWindow(…) in dialog box’s
initialization stage. However, there is an easier approach to it: we can resize the dialog template and move
the unwanted controls outside the template (Figure 7-7). By doing this, these controls will not be shown in
the dialog box, and therefore, can not respond to mouse clicking events.
These controls
are move outside
the dialog
template
Figure 7-7. Custom color dialog template
However, in Developer Studio, a control is confined within the dialog template and is not allowed to
be moved outside it. A workaround for this is to edit the resource file directly. Actually, a dialog template
is based on a text format resource file. In our sample, all type of resources are stored in file “CDB.rc”. By
opening it in “Text” mode, we can find the session describing the color dialog template:
……
CHOOSECOLOR DIALOG DISCARDABLE 2, 0, 150, 124
STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
CAPTION "Color"
FONT 8, "Helv"
BEGIN
END
LTEXT
CONTROL
"&Basic Colors:",-1,4,4,140,9
"",COLOR_BOX1,"Static",SS_SIMPLE | WS_GROUP | WS_TABSTOP,
59,14,85,86
The first four lines specify the properties of this dialog template, which include its dimension, styles,
caption, and font. Between “BEGIN” and “END” keywords, all controls included in the template are listed.
Each item is defined with a type description followed by a series of styles. In the above example, the first
item is a static text control (LTEXT), which contains text “Basic Colors” ("&Basic Colors:"). It has an ID
of 65535 (-1), located at (4, 4), and its dimension is (140, 9).
In the above example, if we change a control’s horizontal coordinate to a value bigger than 150
(Because the dimension of the dialog template is 150×124), it will be moved outside the template.
In the sample, two such dialog templates are prepared: “CHOOSECOLOR” and “CHOOSECUSCOLOR”. In
“CHOOSECOLOR”, static text control COLOR_BOX1 is inside the template, and the area within this control will
be used to draw base colors. For “CHOOSECUSCOLOR”, static text control COLOR_CUSTOM1 is inside the
template, the area within this control will be used to draw custom colors (COLOR_BOX1 and COLOR_CUSTOM1
are used to define an area where the controls will be created dynamically for displaying colors). In both
cases, frame COLOR_CURRENT is inside the template, which will be used to display the current selected color.
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