Note that each data point in the series of the chart has a corresponding label. You can control the visibility of the those labels with the ShowLabels property of the series. However, you should keep in mind that this property will show (or hide) only the labels of the data points in the series where the property is set.
On the other hand the SmartLabels strategy is used to position the labels of the points so that they don't overlap one another. This strategy is helpful when you have a large number of points with displayed labels.
Thank you for the attachment but I don't think I can understand what is your requirement. Can you send me another drawing which demonstrates the expected result. This will help me in understanding your scenario better. In addition you can take a look at our SmartLabels demo and also the Label Customization demo which demonstrates how you can customize the appearance of the labels in the series.
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