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ActivityDesigner.OnMouseDragBegin Method

Occurs when the user starts to drag the mouse on the designer.

Namespace:  System.Workflow.ComponentModel.Design
Assembly:  System.Workflow.ComponentModel (in System.Workflow.ComponentModel.dll)

protected virtual void OnMouseDragBegin(
	Point initialDragPoint,
	MouseEventArgs e


Type: System.Drawing.Point

A Point that represents a single x,y coordinate.

Type: System.Windows.Forms.MouseEventArgs

A MouseEventArgs that contains the event data..

The following describes how and when events related to drag-and-drop operations are raised.

If the designer is a valid drop target, the OnGiveFeedback event is raised with the drag-and-drop effect specified. For a list of drag-and-drop effects, see the DragDropEffects enumeration.

  • Changes in the pointer position, keyboard state, and mouse button state are tracked.

  • If the user moves out of the designer bounds, the OnDragLeave event is raised.

  • If the mouse enters another designer, the OnDragEnter for that designer is raised.

  • If the mouse moves but stays within the same designer, the OnDragOver event is raised.

  • If there is a change in the keyboard or mouse button state, the OnQueryContinueDrag event is raised and determines whether to continue the drag, to drop the data, or to cancel the operation based on the value of the Action property of the event QueryContinueDragEventArgs.

If the value is DragAction.Continue, the OnDragOver event is raised to continue the operation and the OnGiveFeedback event is raised with the new effect so appropriate visual feedback can be set. For a list of valid drop effects, see the DragDropEffects enumeration.


The OnDragOver and OnGiveFeedback events are paired so that as the mouse moves across the drop target, the user is supplied with the most up to date feedback on the mouse position.

If the value is DragAction.Drop, the drop effect value is returned to the source, so that the source application can perform the appropriate operation on the source data; for example, cut the data if the operation was a move.

If the value is DragAction.Cancel, the OnDragLeave event is raised.

For more information about handling events, see Consuming Events.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0