Column resize event

[JP]

Hello,

Is there an event that is raised when a column is resized?  If not, do you have any suggestions about how to get notified whenever a column is resized?

Thanks,

Joel

[Hristo Deshev]

Hello Joel,

We do not expose such an event at the moment. I found a relatively easy way to get notified when that happens. The header cells are placed in a Grid panel inside the header row. Each cell has a GridViewSplitter control beside it. A GridViewSplitter contains a Thumb control that we use for its DragDelta event. DragDelta is a bubbling event that you can handle on the RadGridView control:

<telerik:RadGridView Name="RadGridView1" Thumb.DragDelta="OnHeaderSplitterDrag">
</telerik:RadGridView>

The hard part is getting the right cell and its column definition. Here is the code that does that:

private void OnHeaderSplitterDrag(object sender, DragDeltaEventArgs e)
{
    var dragThumb = (DependencyObject) e.OriginalSource;
    var headerSplitter = (UIElement) VisualTreeHelper.GetParent(dragThumb);
    var headerRowGrid = (Grid) VisualTreeHelper.GetParent(headerSplitter);
    var splitterIndex = headerRowGrid.Children.IndexOf(headerSplitter);
    var cellColumnDefinitionIndex = (splitterIndex - 1) / 2;
    var width = headerRowGrid.ColumnDefinitions[cellColumnDefinitionIndex].Width;

    this.Title = "column resized to: " + width;
}

I hope that does the job for you.

Best wishes,
Hristo Deshev
the Telerik team

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[JP]

Hi Hristo,

This solution worked great, once I made a couple adjustments.  When I ran the code, the OriginalSource of the event was already a GridViewHeaderSplitter object, so I got rid of that line of code.  Also, the event seemed to get fired when the grid was scrolled too.  Below is the code I ended up with.

        private void OnHeaderSplitterDrag(object sender, System.Windows.Controls.Primitives.DragDeltaEventArgs e)
        {
            var headerSplitter = e.OriginalSource as GridViewHeaderSplitter;

            if (headerSplitter != null)
            {
                var headerRowGrid = (Grid)VisualTreeHelper.GetParent(headerSplitter);
                var splitterIndex = headerRowGrid.Children.IndexOf((UIElement)headerSplitter);
                var cellColumnDefinitionIndex = (splitterIndex - 1) / 2;
                var width = headerRowGrid.ColumnDefinitions[cellColumnDefinitionIndex].Width;

                this.Title = "column resized to: " + width;
            }
        }