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Binding ItemsSource to ObservableCollection<BaseClass> causes exception

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GridView

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Evan asked on 24 Sep 2010, 09:59 PM

I have a RadGridView set up to handle displaying a number of reports, and the user story says that I need to get the configuration information for each of them into the detail view, but the configuration information is different for each one (potentially). So I created a base class that contains all the common information, and then concrete classes for the specific implementations, I load an observable collection of the base class with the concrete classes and assign that to the ItemsSource and i get an exception telling me that it can't cast from one concrete class to another (second concrete class type in list to first concrete class type in list).

Does the ItemsSource not recognize the base class i'm using in my observable collection? Any suggestions for how to work around this? The RowLoaded event is handling the loading of the data templates for the different class types (if I can get them loaded into the grid).

I have tried to include all the relevant information for perusal:

RadGridView Version:

2009.3.1208.1030

Property:

private ObservableCollection<ReportDefinitionVMBase> activeReports;

public ObservableCollection<ReportDefinitionVMBase> ActiveReports

{

get

{

return this.activeReports;

}

set

{

this.activeReports = value;

PropertyChangedHandler("ActiveReports");

}

Binding:

<grid:RadGridView Name="reportGrid"

Grid.Row="2"

Opacity="1"

ColumnsWidthMode="Fill"

CanUserResizeColumns="False"

VerticalAlignment="Top"

AutoGenerateColumns="False"

IsReadOnly="False"

RowIndicatorVisibility="Collapsed"

CanUserFreezeColumns="False"

UseAlternateRowStyle="True"

ColumnBackground="{x:Null}"

ShowGroupPanel="False"

CanUserReorderColumns="False"

IsFilteringAllowed="False"

RowDetailsVisibilityMode="VisibleWhenSelected"

Background="Transparent"

Width="Auto"

Height="Auto"

ItemsSource="{Binding ActiveReports}"

Style="{StaticResource RadGridViewSettings}"

RowLoaded="ReportRowLoadedHandler"

>

Exception:

System.InvalidCastException was unhandled by user code

Message="Unable to cast object of type 'Ceridian.Hrpr.Sl.Payroll.ReportOptions.PayrollSummaryVM' to type 'Ceridian.Hrpr.Sl.Payroll.ReportOptions.RegisterVM'."

StackTrace:

at System.Linq.Enumerable.<CastIterator>d__aa`1.MoveNext()

at Telerik.Windows.Data.QueryableCollectionView.PopulateInternalList(IQueryable view)

at Telerik.Windows.Data.QueryableCollectionView.CreateInternalList()

at Telerik.Windows.Data.QueryableCollectionView.EnsureInternalList()

at Telerik.Windows.Data.QueryableCollectionView.get_InternalList()

at Telerik.Windows.Data.QueryableCollectionView.get_IsEmpty()

at Telerik.Windows.Controls.GridView.BaseItemsControl.OnItemCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)

at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)

at Telerik.Windows.Data.DataItemCollection.OnCollectionChanged(NotifyCollectionChangedEventArgs e)

at Telerik.Windows.Data.DataItemCollection.SetItemsSource(IEnumerable source)

at Telerik.Windows.Controls.GridView.GridViewDataControl.<>c__DisplayClass47.<Bind>b__46()

at Telerik.Windows.Controls.CursorManager.PerformTimeConsumingOperation(FrameworkElement frameworkElement, Action action)

at Telerik.Windows.Controls.GridView.GridViewDataControl.Bind(Object newValue)

at Telerik.Windows.Controls.GridView.GridViewDataControl.OnItemsSourceChanged(Object oldValue, Object newValue)

at Telerik.Windows.Controls.DataControl.OnItemsSourcePropertyChanged(DependencyObject origin, DependencyPropertyChangedEventArgs args)

at Telerik.Windows.PropertyMetadata.<>c__DisplayClass1.<Create>b__0(DependencyObject d, DependencyPropertyChangedEventArgs e)

at System.Windows.DependencyObject.RefreshExpression(DependencyProperty dp)

at System.Windows.Data.BindingExpression.RefreshExpression()

at System.Windows.Data.BindingExpression.SendDataToTarget()

at System.Windows.Data.BindingExpression.SourcePropertyChanged(PropertyPathListener sender, PropertyPathChangedEventArgs args)

at System.Windows.PropertyPathListener.RaisePropertyPathStepChanged(PropertyPathStep source)

at System.Windows.PropertyAccessPathStep.RaisePropertyPathStepChanged(PropertyListener source)

at System.Windows.CLRPropertyListener.SourcePropertyChanged(Object sender, PropertyChangedEventArgs args)

at System.Windows.Data.WeakPropertyChangedListener.PropertyChangedCallback(Object sender, PropertyChangedEventArgs args)

at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)

at Ceridian.Core.Sl.Infrastructure.ViewModelBase.PropertyChangedHandler(String propertyName, Boolean setDirtyBit)

at Ceridian.Core.Sl.Infrastructure.ViewModelBase.PropertyChangedHandler(String propertyName)

at Ceridian.Hrpr.Sl.Payroll.ReportOptions.ReportOptionsVM.set_ActiveReports(ObservableCollection`1 value)

at Ceridian.Hrpr.Sl.Payroll.ReportOptions.ReportOptionsVM.LoadActiveReportDetails(ObservableCollection`1 detailList)

at Ceridian.Hrpr.Sl.Payroll.ReportOptions.ReportOptionsVM.<LoadReports>b__0(Object o, GetReportingOptionsSummaryDetailsCompletedEventArgs e)

at Ceridian.Core.Sl.Infrastructure.ViewModelBase.<>c__DisplayClass6`1.<CallService>b__4(Event`1 p)

at System.Collections.Generic.AnonymousObserver`1.Next(T value)

at System.Collections.Generic.AbstractObserver`1.OnNext(T value)

at System.Collections.Generic.AnonymousObservable`1.AutoDetachObserver.Next(T value)

at System.Collections.Generic.AbstractObserver`1.OnNext(T value)

at System.Linq.Observable.<>c__DisplayClasse2`1.<>c__DisplayClasse4.<FromEvent>b__df(Object sender, TEventArgs eventArgs)

at System.EventHandler`1.Invoke(Object sender, TEventArgs e)

at HrprPayrollDomainServiceClient.OnGetReportingOptionsSummaryDetailsCompleted(Object state)

InnerException:

5 Answers, 1 is accepted

answered on 30 Sep 2010, 03:00 PM

Vlad,

rather than try the upgrade path (which I don't have control over) I have done a workaround: I've combined all of the properties that can exist between all of the different types of option screens and I'm switching out the template using the RowLoaded event and examining the properties on the DataItem.

If you can guarantee me that this will work differently in an upgraded version I can put that information forward for the developers on the "core" team to consider, but in an enterprise environment, with so many different teams and responsibilities, etc. I can't push an upgrade to a control or toolkit.

Regards,

Evan

Binding ItemsSource to ObservableCollection&lt;BaseClass&gt; causes exception

5 Answers, 1 is accepted

Binding ItemsSource to ObservableCollection<BaseClass> causes exception