Chart zoom problem

Hello,

It's been a while since I worked with the chart, mainly because it's been working great. I recently did an update from version 6 of WPF Elements to version 7 (nightly). I found that some things aren't working as they did before. Some of the problems are solved, but one problem still remains.

We do our own zoom functionality, because we let the database decide what values are important (we have very large datasets and high load on the server, and we don't want to add too much load on the database). When zooming in, we replace the series in the chart with zoomed series, and when we zoom out, we restore the old non-zoomed series. We do the zooming by hooking in to the internal zoom events (mouse click+drag), and we add an additional check that's kind of special - when you drag to the left, we trigger a zoom out, when dragging to the right we zoom in.

We also have a button in another view that resets the zoom. This triggers the exact same code as when done by mouse.

The problem is that the mouse events work perfectly, but the button restores the axes but NOT the series (visually). The chart doesn't seem to redraw anything when restoring the series. I think that the mouse events internally causes the chart to redraw, but the button does not.

Is there a way to force the chart to redraw from code?

Best regards, Roland

Hi Roland,

There is a method on the Chart control called ForceRender which may help you here. If not, please send me a repro project and I'll fix this issue for you.

-Jason Fauchelle

ForceRender didn't help. I solved it, though, the same way we did when fixing the panning. It was the same thing.

        axis.Maximum = dataSetMaxValue;
        axis.Minimum = dataSetMinValue;
        axis.ActualMaximum = dataSetMaxValue;
        axis.ActualMinimum = dataSetMinValue;

        if (seriesTag == OwnerModule.SelectedTag)
        {
            ContentViewModel.ChartYAxis.Maximum = dataSetMaxValue;
            ContentViewModel.ChartYAxis.Minimum = dataSetMinValue;
            ContentViewModel.ChartYAxis.ActualMaximum = dataSetMaxValue;
            ContentViewModel.ChartYAxis.ActualMinimum= dataSetMinValue;
        }

I had to set all 4 properties, in that order, to make it work.

Great to hear you solved it!

-Jason Fauchelle