The EventManager controls whether events are fired. It provides an easy way to disable the firing of events.
The following sample code illustrates how the event manager can be used to temporarily enable/disable events.
Imports Infragistics.Win.UltraWinTree
Private Sub button20_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button20.Click
If Me.ultraTree1.ActiveNode Is Nothing Then Return
Dim eventManager As TreeEventManager
' Get the tree'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.
eventManager = Me.ultraTree1.EventManager
' Disable the Before/AfterSelect events
eventManager.SetEnabled(TreeEventIds.BeforeSelect, False)
eventManager.SetEnabled(TreeEventIds.AfterSelect, False)
' Toggle the selection state of the active node.
' Note: This would normally cause the Before/AfterSelect
' events to be raised. However, since the above code
' disabled the events they won't be.
Me.ultraTree1.ActiveNode.Selected = Not Me.ultraTree1.ActiveNode.Selected()
' Re-enable the Before/AfterSelect events
eventManager.SetEnabled(TreeEventIds.BeforeSelect, True)
eventManager.SetEnabled(TreeEventIds.AfterSelect, 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 Not eventManager.AllEventsEnabled Then
eventManager.AllEventsEnabled = True
End If
' The event manager also exposes an 'IsEnabled' method
' to see if an event is enabled or disbled.
If Not eventManager.IsEnabled(TreeEventIds.BeforeSelect) Then
eventManager.SetEnabled(TreeEventIds.BeforeSelect, True)
End If
' The tree 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 Not eventManager.IsEnabled(EventGroups.BeforeEvents) Then
eventManager.SetEnabled(EventGroups.BeforeEvents, True)
End If
' 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(TreeEventIds.BeforeSelect) Then
' ...
End If
eventManager.SetEnabled(EventGroups.AfterEvents, True)
End Sub
using Infragistics.Win.UltraWinTree;
private void button20_Click(object sender, System.EventArgs e)
{
if ( this.ultraTree1.ActiveNode == null )
return;
// Get the tree'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.
TreeEventManager eventManager = this.ultraTree1.EventManager;
// Disable the Before/AfterSelect events
eventManager.SetEnabled( TreeEventIds.BeforeSelect, false );
eventManager.SetEnabled( TreeEventIds.AfterSelect, false );
// Toggle the selection state of the active node.
// Note: This would normally cause the Before/AfterSelect
// events to be raised. However, since the above code
// disabled the events they won't be.
this.ultraTree1.ActiveNode.Selected =
!this.ultraTree1.ActiveNode.Selected;
// Re-enable the Before/AfterSelect events
eventManager.SetEnabled( TreeEventIds.BeforeSelect, true );
eventManager.SetEnabled( TreeEventIds.AfterSelect, 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 disbled.
if ( !eventManager.IsEnabled(TreeEventIds.BeforeSelect ) )
eventManager.SetEnabled(TreeEventIds.BeforeSelect, true );
// The tree 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( TreeEventIds.BeforeSelect ) )
{
// ...
}
}
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
