By default, the AllowLinkBars property is True. The AllowLinkBars property specifies whether the user can click a bar, and drag the link to a new bar. Use the ShowLink property to show or hide the links in the chart area. If the ShowLink property is False, the AllowLinkBars has no effect. Linking the bars using the mouse works like follows. The user clicks the bar where the link wants to start, and while keeping the left mouse button, he drags up or down the mouse, until the cursor us changed to a link cursor, and from there the user can select a new bar to link to. Once that the user releases the mouse over a bar, the control adds a new link between these two selected bars, if there were no link between bars. Use the AddLink method to add links programmatically. The AddLink event is fired when the control adds a new link between selected bars. 

  

The red circle shows the link cursor and the dot rectangle around the bar that indicates the selected bar to link to. Once that the user releases the mouse on the red circle, the AddLink event is called to specify the key of the link being added. Use the Link property to set or get the properties and options for the specified link.

The following screen shot shows the type of links you can display: