Nevron .NET Vision Documentation
Drag Tools Overview

All drag operations inherit directly or indirectly from the NDragTool class, which suggests that they share a number of common features.

Selection
All drag tools depend on the current selection. As we mentioned in the Selection topic the selection can be modified both programmatically and visually (by the user).
Events

All drag tools raise the BeginDrag, DoDrag, EndDrag and Cancel events. Their meaning and paramters are described in the following table:

Event Description Event argument
BeginDrag Fired before a drag operation is about to begin. An object of type NDragEventArgs containg the mouse coordinates as well as the current key state.
Drag Fired when a drag operation is being processed. An object of type NDragEventArgs containg the mouse coordinates as well as the current key state.
EndDrag Fired after a drag operation has ended. An object of type NDragEventArgs containg the mouse coordinates as well as the current key state.
Cancel Fired if the user pressed the Escape button. A null (Nothing in VB.NET) value.


You subscribe to these events in the following manner:

C#
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someDragTool.BeginDrag += new EventHandler(OnSomeDragToolBeginDrag);
someDragTool.EndDrag += new EventHandler(OnSomeDragToolEndDrag);
someDragTool.Drag += new EventHandler(OnSomeDragToolDoDrag);
someDragTool.Cancel += new EventHandler(OnSomeDragToolCancel);
Visual Basic
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AddHandler someDragTool.BeginDrag, AddressOf OnSomeDragToolBeginDrag
AddHandler someDragTool.EndDrag, AddressOf OnSomeDragToolEndDrag
AddHandler someDragTool.Drag, AddressOf OnSomeDragToolDoDrag
AddHandler someDragTool.Cancel, AddressOf OnSomeDragToolCancel
Cancelling Drag Operations
All drag operations can be cancelled by the user when he/she presses the Esc key. In addition you can programmatically terminate a drag operation by calling the Cancel method of NDragTool class.
Changing the Mouse Drag Button

Most of the drag operations are activated when the user presses the left mouse button and drags the mouse over the chart. An exception to this is the NDataPanTool drag tool which is activated when the user presses the right mouse button key. You can control the mouse action that triggers the drag operation by modifying the BeginDragMouseCommand property of the NDragTool object. The following code will create a trackball tool activated when the user presses the right mouse button:

C#
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NTrackballTool trackballTool = new NTrackballTool();
trackballTool.BeginDragMouseCommand = new NMouseCommand(MouseAction.Down, MouseButtons.Right, 1);

chartControl.Controller.Tools.Add(trackballTool);
Visual Basic
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Dim trackballTool As New NTrackballTool
trackballTool.BeginDragMouseCommand = New NMouseCommand(MouseAction.Down, MouseButtons.Right, 1)

chartControl.Controller.Tools.Add(trackballTool)
Changing the Mouse Cursor

The mouse cursor associated with each drag operation can be modified with the help of the Cursor property of the NDragTool object:

C#
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someDragTool.Cursor = Cursors.Hand;
Visual Basic
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someDragTool.Cursor = Cursors.Hand
See Also

 

 


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