Are there any sources for line/spark charts with zoom and vertical selection such as selecting a point, and returning the index of the data at that point, while drawing a vertical line?
Each sparkline is implemented as a single Shape whose Geometry is a long sequence of straight lines. Each shape is normally considered a “black box” so there is no built-in functionality such as what you propose.
It sounds to me as if you need a custom click event handler that finds the index of the data for the X value (in local coordinates) of the mouse point and a custom selection Adornment that shows a vertical line there.
If I get a chance later today I can work on this for you.
Try this: Sparkline Graphs with click information Basically the only change I made was to the node template.
There’s now a click event handler on the node (template) that looks where the click occurred, which line (array of values) the click point is closest to, and save that information on the node data object.
There’s now also a custom selection Adornment that is data bound to those new properties. It shows a colored vertical line where the user clicked. The color matches the color of the closest chart line. There’s also a TextBlock showing the closest line number, the closest “time” value index into the values arrays, and the data value at that index.