WPF DataGrid column header mouse events

Question

I have following events with subscriptions in the class, derived from DataGrid:

private void SubscribeHeaders(DependencyObject sender = null)
{
    sender = sender ?? this;

    for (int childIndex = 0; childIndex < VisualTreeHelper.GetChildrenCount(sender); childIndex++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(sender, childIndex);
        if (child is DataGridColumnHeader colHeader)
        {
            //Subscribe column headers
            colHeader.PreviewMouseLeftButtonDown += (obj, e) => OnColumnHeaderMouseDown(obj, e);
            colHeader.PreviewMouseLeftButtonUp += (obj, e) => OnColumnHeaderMouseUp(obj, e);
            colHeader.MouseEnter += (obj, e) => OnColumnHeaderMouseEnter(obj, e);
            colHeader.MouseLeave += (obj, e) => OnColumnHeaderMouseLeave(obj, e);

        }
        else if (child is DataGridRowHeader rowHeader)
        {
            //Subscribe row headers
        }
        else
        {
            SubscribeHeaders(child);
        }
    }
}

Everything binds fine, but OnColumnHeaderMouseEnter(obj, e) is not executed, while mouse button is pressed. It doesn't seem like mouse is captured,

if (Mouse.Captured != null)
    Mouse.Captured.ReleaseMouseCapture();

does not change anything, since Mouse.Captured is always null.

What I'm trying to achieve is to select a range of DataGrid columns by dragging a mouse with a pressed left button from start to the end of selection. My idea is to react on mouse buttons and movements from header to header.

How can I capture movements between DataGridColumnHeaders with a mouse button pressed?

Answer 1

I will give you a workaround with getting the selection by event SelectedCellsChanged.
1.Make the DataGrid with the below setting:

SelectedCellsChanged="Dg_SelectedCellsChanged" SelectionMode="Extended" SelectionUnit="CellOrRowHeader" 

2.Then get the each selectedCell like this:

 private void Dg_SelectedCellsChanged(object sender, SelectedCellsChangedEventArgs e)
        {
            foreach (DataGridCellInfo info in dataGrid.SelectedCells)
            {
                FrameworkElement element = info.Column.GetCellContent(info.Item);
                string str = ((TextBlock)info.Column.GetCellContent(info.Item)).Text;
                Console.WriteLine(str);
            }
        }