Column and Row Resize Events

Updated on Oct 7, 2026

When the user resizes a column or a row through the UI, RadVirtualGrid raises events that let you restrict the operation and react to its result. This article explains how to use the ColumnWidthChanging, ColumnWidthChanged, RowHeightChanging, and RowHeightChanged events.

The events are raised only for resizing performed by the user through the UI. Column resizing requires the CanUserResizeColumns property to be True (the default value), and row resizing requires the CanUserResizeRows property to be True. For more information, see Column and Row Resizing.

Resize Events Overview

The following table describes when each event is raised.

Event	Event arguments	Description
ColumnWidthChanging	VirtualGridColumnWidthChangingEventArgs	Raised while a column is being resized, on each step of the drag operation. Can be canceled.
ColumnWidthChanged	VirtualGridColumnWidthChangedEventArgs	Raised once after the user finishes resizing a column.
RowHeightChanging	VirtualGridRowHeightChangingEventArgs	Raised while a row is being resized, on each step of the drag operation. Can be canceled.
RowHeightChanged	VirtualGridRowHeightChangedEventArgs	Raised once after the user finishes resizing a row.

The event arguments of the column events expose the following properties:

Property	Type	Description
ColumnIndex	int	The index of the column being resized.
OldWidth	double	The width of the column before the resize operation started.
NewWidth	double	The new width of the column. In the ColumnWidthChanging event, this is the width that is about to be applied. In the ColumnWidthChanged event, this is the final width.

The event arguments of the row events expose the following properties:

Property	Type	Description
RowIndex	int	The index of the row being resized.
OldHeight	double	The height of the row before the resize operation started.
NewHeight	double	The new height of the row. In the RowHeightChanging event, this is the height that is about to be applied. In the RowHeightChanged event, this is the final height.

The VirtualGridColumnWidthChangingEventArgs and VirtualGridRowHeightChangingEventArgs classes inherit from CancelEventArgs, so they also expose the Cancel property.

Restricting the Resize Operation

Use the ColumnWidthChanging and RowHeightChanging events to prevent the user from resizing a column or a row to an unwanted size. Set the Cancel property of the event arguments to True to skip the pending size change. Because the events are raised on each step of the drag operation, the column or row keeps the last size that was not canceled.

The following example prevents the user from making the first column wider than 300 pixels and the rows taller than 80 pixels.

Subscribing to the resize events

xml

<telerik:RadVirtualGrid x:Name="virtualGrid"
                        CanUserResizeRows="True"
                        InitialColumnCount="5"
                        InitialRowCount="20" />

C#

this.virtualGrid.ColumnWidthChanging += this.VirtualGrid_ColumnWidthChanging;
this.virtualGrid.RowHeightChanging += this.VirtualGrid_RowHeightChanging;

Canceling the resize operation

C#

private void VirtualGrid_ColumnWidthChanging(object sender, VirtualGridColumnWidthChangingEventArgs e)
{
    if (e.ColumnIndex == 0 && e.NewWidth > 300)
    {
        e.Cancel = true;
    }
}

private void VirtualGrid_RowHeightChanging(object sender, VirtualGridRowHeightChangingEventArgs e)
{
    if (e.NewHeight > 80)
    {
        e.Cancel = true;
    }
}

The VirtualGridColumnWidthChangingEventArgs and VirtualGridRowHeightChangingEventArgs classes are defined in the Telerik.Windows.Controls.VirtualGrid namespace.

Reacting to the Completed Resize

Use the ColumnWidthChanged and RowHeightChanged events to run logic after the user releases the mouse button and the resize operation completes. The OldWidth and OldHeight properties hold the size at the start of the operation, and NewWidth and NewHeight hold the final size.

The following example stores the final column widths and row heights so that they can be restored later.

Storing the resized dimensions

C#

private readonly Dictionary<int, double> columnWidths = new Dictionary<int, double>();
private readonly Dictionary<int, double> rowHeights = new Dictionary<int, double>();

private void SubscribeToResizedEvents()
{
    this.virtualGrid.ColumnWidthChanged += this.VirtualGrid_ColumnWidthChanged;
    this.virtualGrid.RowHeightChanged += this.VirtualGrid_RowHeightChanged;
}

private void VirtualGrid_ColumnWidthChanged(object sender, VirtualGridColumnWidthChangedEventArgs e)
{
    this.columnWidths[e.ColumnIndex] = e.NewWidth;
}

private void VirtualGrid_RowHeightChanged(object sender, VirtualGridRowHeightChangedEventArgs e)
{
    this.rowHeights[e.RowIndex] = e.NewHeight;
}

See Also

• Column and Row Resizing
• Headers
• Telerik UI for WPF API Reference