GenValue: 3.6 GenValue Basics: Sending an Action

GVLI_applyMsg, GVLI_destination, HINT_VALUE_NAVIGATE_TO_NEXT_FIELD_ON_RETURN_PRESS, HINT_VALUE_CUSTOM_RETURN_PRESS, MSG_GEN_VALUE_GET_APPLY_MSG, MSG_GEN_VALUE_SET_APPLY_MSG, MSG_GEN_VALUE_GET_DESTINATION, MSG_GEN_VALUE_SET_DESTINATION

GVLI_ applyMsg sets the message for the GenValue to send out whenever it has been modified and needs to apply its changes. Whenever a GenValue receives MSG_GEN_APPLY, i t will check whether its GVSF_MODIFIED flag has been set; if it has, it will send out its apply message. If a GenValue is operating in immediate mode, these actions will happen immediately, resulting in an immediate action.

GVLI_ destination specifies the destination object (or process) to send the GVLI_applyMsg to. (This may also be a TravelOption , such as TO_APP_TARGET.)

Code Display 8-8 Sending an Apply Message

@object GenValueClass MyValue = {
    GI_visMoniker = "My Value";
    GVLI_value = MakeWWFixed(1.0);
    GVLI_applyMsg = MSG_MY_VALUE_DOUBLE_VALUE;
    GVLI_destination = process;
}

/* Retrieve the current value. This value will be a fixed point dword. */

@method MyValueProcessClass, MSG_MY_VALUE_DOUBLE_VALUE {
    WWFixedAsDWord	curValue;

    curValue = @call MyValue::MSG_GEN_VALUE_GET_VALUE();
    curValue = curValue*2;
    @call MyValue::MSG_GEN_VALUE_SET_VALUE(curValue, 0);
}

A GenValue's changes are typically applied when the user hits the Return key and the GenValue has the focus. You can change this behavior, though, with the following hints: HINT_VALUE_CUSTOM_RETURN_PRESS allows a textually-oriented GenValue to send the specified message to the destination object when the Return key is pressed. HINT_VALUE_NAVIGATE_TO_NEXT_FIELD_ON_RETURN_PRESS instructs the GenValue to navigate (via the UI) to the next textually-activated object (as the tab key works in many situations).

To change a GenValue's apply message or destination, send it MSG_GEN_VALUE_SET_APPLY_MSG or MSG_GEN_VALUE_SET_DESTINATION , respectively. Use MSG_GEN_VALUE_GET_APPLY_MSG or MSG_GEN_VALUE_GET_DESTINATION to return the current apply message or destination.

The apply message should be defined on the prototype GEN_VALUE_APPLY_MSG , whose values are shown below.

GEN_VALUE_APPLY_MSG

void	GEN_VALUE_APPLY_MSG(
        WWFixedAsDWord		value,
        word		stateFlags);

This prototype defines the message sent out when the GenValue is "applied." The output of the GenValue should handle a message with these parameters.

Source: GenValue, when "applied."

Destination: The GenValue's output (GVLI_destination ) object.

Parameters: value The current value of the GenValue.

stateFlags: The GenValueStateFlags stored in GVLI_stateFlags .

Return: Nothing.

Interception: The destination object should handle the apply message with this format.

MSG_GEN_VALUE_GET_APPLY_MSG

Message	MSG_GEN_VALUE_GET_APPLY_MSG();

This message returns the GenValue's GVLI_applyMsg .

Source: Unrestricted.

Destination: Any GenValue object.

Parameters: None.

Return: The apply message of the GenValue.

Interception: Generally not intercepted.

MSG_GEN_VALUE_SET_APPLY_MSG

void	MSG_GEN_VALUE_SET_APPLY_MSG(
        Message		message);

This message sets the apply message (in GVLI_applyMsg ) for a GenValue.

Source: Unrestricted.

Destination: Any GenValue object.

Parameters: message The apply message to set for the GenValue.

Return: Nothing.

Interception: Generally not intercepted.

MSG_GEN_VALUE_GET_DESTINATION

optr	MSG_GEN_VALUE_GET_DESTINATION();

This message returns the current destination object (or process) that the GenValue sends its apply messages to.

Source: Unrestricted.

Destination: Any GenValue object.

Parameters: None.

Return: The destination optr (GVLI_destination ) of the GenValue.

Interception: Generally not intercepted.

MSG_GEN_VALUE_SET_DESTINATION

void	MSG_GEN_VALUE_SET_DESTINATION(
        optr	dest);

This message sets the GVLI_destination field of the range to the passed optr. The object can be a pointer to a specific object in the system (i.e. the GenProcess object) or can be a pointer to a generic location in the system (i.e. a TravelOption ).

Source: Unrestricted.

Destination: Any GenValue object.

Parameters: dest The optr of the new destination object.

Return: Nothing.

Interception: Generally not intercepted.

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