BeforeDropDown Event (UltraCombo)

Occurs before the list portion of the combo is dropped down.

Syntax

Visual Basic

'Declaration
 
Public Event BeforeDropDown As CancelEventHandler

C#

public event CancelEventHandler BeforeDropDown

Event Data

The event handler receives an argument of type CancelEventArgs containing data related to this event. The following CancelEventArgs properties provide information specific to this event.

Property	Description
Cancel

Remarks

You can use this event to examine or change attributes of the list before it is displayed to the user. You can also use this event to cancel the dropdown of the list before it occurs.

Note that this event does not fire for editor button (buttons in the ButtonsLeft or ButtonsRight collection. To trap events for Infragistics.Win.UltraWinEditors.DropDownEditorButtons, use the BeforeEditorButtonDropDown event.

Example

Following code illustrates how one can use BeforeDropDown event to prevent the user from dropping down an UltraCombo's drop down by canceling the event.

For an overview of how to handle events in Visual Basic or Visual C#, see Event Handlers in Visual Basic and Visual C#. For specific information and code examples illustrating how to consume events in your application, see Consuming Events in the .NET Framework Developer's Guide.

Visual Basic

Imports Infragistics.Shared
Imports Infragistics.Win
Imports Infragistics.Win.UltraWinGrid

  Private Sub UltraCombo1_BeforeDropDown(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles ultraCombo1.BeforeDropDown

      Dim allowDropDown As Boolean = True

      If Not allowDropDown Then
          ' Set Cancel to true to prevent the ultra combo from dropping down.
          e.Cancel = True
      End If

  End Sub

C#

using Infragistics.Shared;
using Infragistics.Win;
using Infragistics.Win.UltraWinGrid;
using System.Diagnostics;

private void ultraCombo1_BeforeDropDown(object sender, System.ComponentModel.CancelEventArgs e)
{

	bool allowDropDown = true;

	if ( !allowDropDown )
	{
		// Set Cancel to true to prevent the ultra combo from dropping down.
		e.Cancel = true;
	}

}

Requirements

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