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ColumnGroups.Add produces null reference exception

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GridView

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Matthew Kruczek asked on 10 Oct 2012, 02:50 PM

The following piece of code...

this.DataGrid.ColumnGroups.Clear();

var groupColumnDef = new GridViewColumnGroup();

groupColumnDef.Header = column.Title;

groupColumnDef.Name = column.Title.GetColumnName();

groupColumnDef.HeaderStyle = this.Resources["s1"] as Style;

groupColumnDef.HeaderTemplate = this.Resources["GroupHeader"] as DataTemplate;

// Add the group

// The current column is top level so just add it

if (!this.DataGrid.ColumnGroups.Contains(groupColumnDef))

this.DataGrid.ColumnGroups.Add(groupColumnDef);

Produces the following error..

base {System.NullReferenceException: Object reference not set to an instance of an object.
at Telerik.Windows.Controls.GridView.CommonHeaderPresenter.ArrangeLowestHeaders()
at Telerik.Windows.Controls.GridView.CommonHeaderPresenter.ArrangeHeaders()
at Telerik.Windows.Controls.GridView.CommonHeaderPresenter.PlaceCommonHeaders()
at Telerik.Windows.Controls.GridView.CommonHeaderPresenter.Rearrangeheaders()
at Telerik.Windows.Controls.GridView.CommonHeaderPresenter.NotifyCellsPropertyChanged(DependencyObject d, String propertyName, DependencyPropertyChangedEventArgs e, UpdateTarget target)
at Telerik.Windows.Controls.GridView.GridViewHeaderRow.NotifyPropertyChanged(DependencyObject d, String propertyName, DependencyPropertyChangedEventArgs e, UpdateTarget target)
at Telerik.Windows.Controls.GridView.GridViewDataControl.NotifyPropertyChanged(DependencyObject d, String propertyName, DependencyPropertyChangedEventArgs e, UpdateTarget target)
at Telerik.Windows.Controls.GridViewColumnCollectionInternal.CalculateColumnWidths(Object arg)} System.Exception {System.NullReferenceException}

Any thoughts as to why?