Hi Wen,
Thanks for using Syncfusion products.The sample url link is currently not available, so we have created a simple sample for displaying date time values in tooltip.
Please refer the following code snippet to achieve this:<code>
[CS]
void series_PrepareStyle(object sender, ChartPrepareStyleInfoEventArgs args)
{
ChartSeries series = sender as ChartSeries;
args.Style.ToolTip = "XValue: " + series.Points[args.Index].DateX + "YValue: " + series.Points[args.Index].YValues[0];
}
<code>
For more information about tooltip, please refer our online documentation in the following link:Please let us know if you have any concern.
Regards,
Anand