The Clipboard: 3.3 Using The Clipboard: The GenEditControl

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As stated above, most applications will simply let a GenEditControl object create and maintain their Edit menu. GenEditControlClass is a subclass of GenControlClass (see the Controllers chapter for usage of controllers in general).

The GenEditControl object can provide triggers and/or tools for Undo, Cut, Copy, Paste, Select All, and Delete operations. These operations must all be handled by your application, of course, just as if you did not use a GenEditControl; using this controller, however, simplifies your UI programming and allows the Edit tools to be used by the GenToolControl.

The features of the GenEditControl are listed below (they are flags of the GECFeatures record type):

GECF_UNDO
This feature adds an "Undo" trigger to the Edit menu. It sends MSG_META_UNDO to the application's target.
GECF_CUT
This feature adds a "Cut" trigger to the Edit menu. When the user activates this, it sends MSG_META_CLIPBOARD_CUT to the application's target.
GECF_COPY
This feature adds a "Copy" trigger to the Edit menu. When the user activates this, it sends MSG_META_CLIPBOARD_COPY to the application's target.
GECF_PASTE
This feature adds a "Paste" trigger to the Edit menu. When the user activates this, it sends MSG_META_CLIPBOARD_PASTE to the application's target.
GECF_SELECT_ALL
This feature adds a "Select All" trigger to the Edit menu. It sends MSG_META_SELECT_ALL to the applications' target.
GECF_DELETE
This feature adds a "Delete" trigger to the Edit menu. When the user activates this, it sends MSG_META_DELETE to the application's target.

The GenEditControl also provides an equivalent set of tools. Each tool executes the exact same functions as the analogous feature; see GenEditControl Features and Tools for the listing of the features and tools as well as the standard settings.

The GenEditControl handles two different notification types: GWNT_SELECT_STATE_CHANGE, sent when the selection state changes, and GWNT_UNDO_STATE_CHANGE, sent when a state change in the Undo status occurs. In both cases, the GenEditControl will appropriately update the Cut, Copy, Paste, Delete, and Undo triggers (the Select All trigger will always be enabled).

Code Display 7-6 GenEditControl Features and Tools

/* This display shows the features and tools records of GenEditControlClass, as
 * well as the default settings and instance data. */
	/* GenEditControlClass features */
typedef WordFlags GECFeatures;
#define GECF_UNDO				0x0020		/* MSG_META_UNDO */
#define GECF_CUT				0x0010		/* MSG_META_CLIPBOARD_CUT */
#define GECF_COPY				0x0008		/* MSG_META_CLIPBOARD_COPY */
#define GECF_PASTE				0x0004		/* MSG_META_CLIPBOARD_PASTE */
#define GECF_SELECT_ALL				0x0002		/* MSG_META_SELECT_ALL */
#define GECF_DELETE				0x0001		/* MSG_META_DELETE */
#define GEC_DEFAULT_FEATURES				(GECF_UNDO | GECF_CUT | GECF_COPY | \
				 GECF_PASTE | GECF_SELECT_ALL | GECF_DELETE)
	/* GenEditControlClass tools */
typedef WordFlags GECToolboxFeatures;
#define GECTF_UNDO				0x0020		/* MSG_META_UNDO */
#define GECTF_CUT				0x0010		/* MSG_META_CLIPBOARD_CUT */
#define GECTF_COPY				0x0008		/* MSG_META_CLIPBOARD_COPY */
#define GECTF_PASTE				0x0004		/* MSG_META_CLIPBOARD_PASTE */
#define GECTF_SELECT_ALL				0x0002		/* MSG_META_SELECT_ALL */
#define GECTF_DELETE				0x0001		/* MSG_META_DELETE */
#define GEC_DEFAULT_TOOLBOX_FEATURES					(GECTF_UNDO | GECTF_CUT | GECTF_COPY |
					 GECTF_PASTE | GECTF_SELECT_ALL |
					 GECTF_DELETE)
	/* GenEditControlClass Instance Data Settings */
    @default GCI_output = (TO_APP_TARGET);						/* Send output to the target */
    @default GI_states = (@default | GS_ENABLED);
    @default GI_attrs = (@default | GA_KBD_SEARCH_PATH);
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