You can add the chart legend using the <Legend> element tag which is defined as a child node of the <Options> element tag.
This sample chart is to show how to display and undisplay the series data when the chart is initially displayed. If you want to undisplay a series data with having the legend item of the series data unchecked, then you must set the value of the visible to "false"
... <Options> <Legend useVisibleCheck="true" markerWidth="12" markerHeight="12" /> </Options> ... <Column3DSeries ... visible="false" > ... <Column3DSeries ... visible="false" > ... <Column3DSeries ... visible="true" > ...
|useVisibleCheck||The useVisibleCheck attribute determines whether or not to use the checkbox in the chart legend. you cannot use the checkbox in the chart legend for the pie or doughnut chart.|
|markerWidth||The markerWidth attribute is to set the width of the shape which represents the series data.|
|markerHeight||The markerHeight attribute is to set the height of the shape which represents the series data.|