Questions

Hi Anil

You can control the SciChartSurface directly from the ViewModel by following this technique:

ViewportManager – Full Control over Axis Ranges and Viewport

You can call the following functions on a ViewportManager from a ViewModel. Use these to have direct control over the SciChartSurface in absence of a SciChartSurface instance itself.

Assuming you have bound a ViewportManager as per Declaring a Binding to a ViewportManager in MVVM

public class MyViewModel : INotifyPropertyChanged
{
    // Viewmodel
       private DefaultViewportManager _viewportManager = new DefaultViewportManager();
       public IViewportManager ViewportManager
       {
          get { return _viewportManager; }
          set
          {
               _viewportManager = value;
               OnPropertyChanged("ViewportManager");
          }
       }

       public void Foo()
       {
             // All things you can do from the ViewModel with a ViewportManager
             // We don't recommend doing them all at once! :)
             _viewportManager.ZoomExtents();
              _viewportManager.AnimateZoomExtents(TimeSpan.FromMilliseconds(500));
             _viewportManager.ZoomExtentsY();
             _viewportManager.AnimateZoomExtentsY(TimeSpan.FromMilliseconds(500));
             _viewportManager.ZoomExtentsX();
             _viewportManager.AnimateZoomExtentsX(TimeSpan.FromMilliseconds(500));
       }
}

Note that there may be a short delay between setting data and being able to zoom to extents on it. This is because of the delay in binding in WPF itself.

In order to work around this delay, we recommend a technique like this:

            // Invoke AnimateZoomExtents after binding engine has stabilised 
            _viewportManager.BeginInvoke(() =>
            {
                var duration = TimeSpan.FromMilliseconds(250);
                _viewportManager.AnimateZoomExtents(duration);                    
            });

Best regards,
Andrew