Gets an object used to indicate the expected drop location when an item is dragged within a ListView control.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The ListView insertion mark feature lets you visually indicate the expected drop location in a drag-and-drop operation when an item is dragged to a new position. This feature works only when the AutoArrange property is set to true and when the ListView control does not sort the items automatically. To prevent automatic sorting, the Sorting property must be set to SortOrder.None and the View property must be set to View.LargeIcon, View.SmallIcon, or View.Tile. Additionally, the insertion mark feature may not be visible with the ListView grouping feature because the grouping feature orders the items by group membership.
The ListViewInsertionMark class is typically used in a handler for the Control.DragOver or Control.MouseMove event to update the position of the insertion mark as an item is dragged. It is also used in a handler for the Control.DragDrop or Control.MouseUp event to insert a dragged item at the correct location. For more information, see ListViewInsertionMark and How to: Display an Insertion Mark in a Windows Forms ListView Control.
The insertion mark feature is available only on Windows XP and Windows Server 2003 when your application calls the Application.EnableVisualStyles method. On earlier operating systems, any code relating to the insertion mark has no effect and the insertion mark will not appear. As a result, any code that depends on the insertion mark feature might not work correctly. You might want to include code that determines whether this feature is available, and provide alternate functionality when it is unavailable. For example, you might want to bypass all code that implements drag-and-drop item repositioning when running on operating systems that do not support insertion marks.
The insertion mark feature is provided by the same library that provides the operating system themes feature. To check for the availability of this library, call the FeatureSupport.IsPresent(Object) method overload and pass in the OSFeature.Themes value.
The following code example demonstrates how to use the ListView insertion mark feature. This example implements drag-and-drop item reordering using the standard drag events. The position of the insertion mark is updated in a handler for the Control.DragOver event. In this handler, the position of the mouse pointer is compared to the midpoint of the nearest item, and the result is used to determine whether the insertion mark appears to the left or the right of the item.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.