WPF/MVVM: Sync scrolling of two datagrids in different views

Question

I have two datagrids side by side bound to different data tables and each with their own view.

The datatables both have the same number of rows, and I want both grids to maintain the same scroll position.

I am having trouble finding a way to do this using MVVM... anyone have any ideas?

Thanks! -Steven

score 8 · Accepted Answer · answered May 14 '10 at 20:00

8

Take a look at codeproject Scroll Synchronization

answered May 14 '10 at 20:00

volody

6,946
3
42
54

Thanks for the quick response! This was exactly what I was looking for, already have it implemented and working :) – stevosaurus May 14 '10 at 20:30

score 8 · Answer 2 · answered Nov 08 '10 at 18:16

I was able to overcome this issue via some reflection hacks:

<DataGrid Name="DataGrid1" ScrollViewer.ScrollChanged="DataGrid1_ScrollChanged" />
<DataGrid Name="DataGrid2" />

and the code itself is:

    private void DataGrid1_ScrollChanged(object sender, ScrollChangedEventArgs e)
    {
        if (e.HorizontalChange != 0.0f)
        {
            ScrollViewer sv = null;
            Type t = DataGrid1.GetType();
            try
            {
                sv = t.InvokeMember("InternalScrollHost", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetProperty, null, DataGrid2, null) as ScrollViewer;
                sv.ScrollToHorizontalOffset(e.HorizontalOffset);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }

+1 for reflection hack. used this in conjunction with the codeproject article to achieve a working attached property implementation for WPF Datagrid — Dr. Andrew Burnett-Thompson, Feb 07 '12 at 13:23

score 4 · Answer 3 · answered Aug 24 '10 at 00:03

4

The Scroll Synchronization project doesn't work for Datagrid because it doesn't expose ScrollToVerticalOffset

answered Aug 24 '10 at 00:03

Michael

641
5
4

score 0 · Answer 4 · answered Jan 26 '14 at 05:45

The best way I've used so far is to use the VisualTreeHelper class to find the correct ScrollViewer object (grid or no grid). I've used this in several projects.

Try this if any of you need it:

private static bool ScrollToOffset(DependencyObject n, double offset)
{
    bool terminate = false;
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(n); i++)
    {
        var child = VisualTreeHelper.GetChild(n, i);
        if (child is ScrollViewer)
        {
            (child as ScrollViewer).ScrollToVerticalOffset(offset);
            return true;
        }
    }
    if (!terminate)
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(n); i++)
            terminate = ScrollToOffset(VisualTreeHelper.GetChild(n, i), offset);
     return false;
}

Note: I typically use ListBox classes and would pass it directly to this function.

Happy programming :)

WPF/MVVM: Sync scrolling of two datagrids in different views

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