Event Managers

Some PLF-based controls expose a convenient facility for temporarily disabling their events and for checking if an event is being raised. The following sample code illustrates how it is used.

using Infragistics.Win;
using Infragistics.Win.UltraWinGrid;

private void button2_Click(object sender, System.EventArgs e)
{
    if (this.ultraGrid1.ActiveRow == null)
        return;

    // Get the grid‘s event manager.
    // The event manager is used to temporarily disable events
    // to prevent them from being raised. This can be very
    // convenient in a situation where one or more properties
    // are being set in code and the events they would normally
    // raise would cause unnecessary or counter-productive
    // code to be executed.
    //
    // Note: All events are enabled by default.
    GridEventManager eventManager = this.ultraGrid1.EventManager;

    // Disable the Before/AfterSelectChange events
    eventManager.SetEnabled(GridEventIds.BeforeSelectChange, false);
    eventManager.SetEnabled(GridEventIds.AfterSelectChange, false);

    // Toggle the selection state of the active row.
    // Note: This would normally cause the Before/AfterSelectChange
    // events to be raised. However, since the above code disabled
    // the events they won‘t be.
    this.ultraGrid1.ActiveRow.Selected = !this.ultraGrid1.ActiveRow.Selected;

    // Re-enable the Before/AfterSelectChange events
    eventManager.SetEnabled(GridEventIds.BeforeSelectChange, true);
    eventManager.SetEnabled(GridEventIds.AfterSelectChange, true);

    // The ‘AllEventsEnabled‘ property lets you enable/disable
    // all events will a single line of code. If any event is
    // disabled the ‘AllEventsEnabled‘ property returns false.
    if (!eventManager.AllEventsEnabled)
        eventManager.AllEventsEnabled = true;

    // The event manager also exposes an ‘IsEnabled‘ method
    // to see if an event is enabled or disabled.
    if (!eventManager.IsEnabled(GridEventIds.BeforeSelectChange))
        eventManager.SetEnabled(GridEventIds.BeforeSelectChange, true);

    // The grid event manager also exposes overloaded
    // ‘IsEnabled‘ and ‘SetEnabled‘ methods that take an
    // event group so that, for example all ‘Before‘ or all
    // ‘After‘ events can be enabled/disabled. If any event
    // in the group is disabled the ‘IsEnabled‘ method returns
    // false.
    if (!eventManager.IsEnabled(EventGroups.BeforeEvents))
        eventManager.SetEnabled(EventGroups.BeforeEvents, true);

    eventManager.SetEnabled(EventGroups.AfterEvents, true);

    // The ‘InProgress‘ method will return true if the
    // specified event is currently being raised. This
    // is often helpful in methods that can be called
    // from various points in an application to determine
    // what is triggering the call.
    if (eventManager.InProgress(GridEventIds.BeforeSelectChange))
    {
        // ...
    }

    // The UltraCombo and UltraDropDown controls also expose
    // event managers for their custom events. However,
    // since they have considerably fewer events they don‘t
    // expose overloaded ‘IsEnabled‘ and ‘SetEnabled‘ methods
    // to control groups of events.
    ComboEventManager comboManager = this.ultraCombo1.EventManager;
    comboManager.SetEnabled(ComboEventIds.BeforeDropDown, true);

    DropDownEventManager dropDownManager = this.ultraDropDown1.EventManager;
    dropDownManager.SetEnabled(DropDownEventIds.AfterCloseUp, true);
}