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The OnClientTileDragStart event is raised when the user starts dragging a tile. It is the first event related to dragging that is fired and can be cancelled. If it is cancelled no other dragging-related event will be fired.

This event can be used to check for a certain condition and prevent drag and drop. For example, the developer may want only certain tiles to be draggable, so this event can be cancelled for the rest.

The event handler receives two arguments:

  1. the RadTileList object that fired the event

  2. an event arguments object that exposes the following methods

OnClientTileDragStart event arguments object

Name Return type Arguments Description
get_cancel() bool Gets a value that indicates whether the event is cancelled.
get_tile() RadBaseTile client-side object Gets a reference to the tile that is clicked.
set_cancel(value) bool Sets whether the event will be cancelled (if true is passed).

The following example shows how a certain condition can be used to prevent the user from dragging certain tiles. In this case the tiles' Name properties contain an indicator whether dragging should be allowed.

<telerik:RadTileList RenderMode="Lightweight" EnableDragAndDrop="true" ID="TileList1" runat="server" OnClientTileDragStart="OnClientTileDragStartHandler">
            <telerik:RadTextTile Name="First" Text="First tile, draggable" runat="server"></telerik:RadTextTile>
            <telerik:RadTextTile Name="SecondNoDrag" Text="Second tile, not draggable" runat="server"></telerik:RadTextTile>
            <telerik:RadTextTile Name="ThirdNoDrag" Text="Third tile, not draggable" runat="server"></telerik:RadTextTile>
            <telerik:RadTextTile Name="Fourth" Text="Fourth tile, draggable" runat="server"></telerik:RadTextTile>
            <telerik:RadTextTile Name="Fifth" Text="Fifth tile, draggable" runat="server"></telerik:RadTextTile>
function OnClientTileDragStartHandler(sender, args)
    var tileName = args.get_tile().get_name();
    if (tileName.indexOf("NoDrag") > -1) args.set_cancel(true);
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