I'm trying to bind the command parameter in XAML for a RelayCommand<MessageTokens> as below, where MessageTokens is an enum
public ICommand OpenInvoiceWindowCommand { get { return _openInvoiceWindowCommand ?? (_openInvoiceWindowCommand = new RelayCommand<MessageTokens>(OpenInvoiceWindow, prm => CanExecuteOpenInvoiceWindowCommand)); } } The XAML is:
<Controls1:RadMenuItem Command="{Binding SupplierInvoiceViewModel.OpenInvoiceWindowCommand}" CommandParameter="{Binding Source={x:Type ShipmentDetails:DebitInvoiceViewModelBase}, Path=MessageTokens.SupplierInvoice}" Header="Register a supplier's invoice"/> Using Telerik's RadGridView the code crashes with
at GalaSoft.MvvmLight.Command.RelayCommand`1.CanExecute(Object parameter) at Telerik.Windows.Controls.RadMenuItem.CanExecuteApply() in c:\Builds\WPF_Scrum\HotFix_2010_Q3\Sources\Development\Controls\Navigation\Menu\RadMenuItem.cs:line 2105 at Telerik.Windows.Controls.RadMenuItem.ChangeCommand(ICommand oldCommand, ICommand newCommand) in c:\Builds\WPF_Scrum\HotFix_2010_Q3\Sources\Development\Controls\Navigation\Menu\RadMenuItem.cs:line 2124 at Telerik.Windows.Controls.RadMenuItem.OnCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) in c:\Builds\WPF_Scrum\HotFix_2010_Q3\Sources\Development\Controls\Navigation\Menu\RadMenuItem.cs:line 1623 at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e) at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e) at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args) at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
etc.
If I change the parameter to RelayCommand<string> instead of RelayCommand<MessageTokens> the code runs fine.
I'm loathe to do this since I lose all the benefits of strongly typing my parameters.
I suspect that I am not declaring the enum properly in XAML. I've tried
CommandParameter = "<fullpath>..MessageTokens.SupplierInvoice>" but that gives an InvalidCastException in MVVMLight.
Does anyone have any suggestions?
Many thanks Jeremy
Edited with the solution
The issue was because I wasn't properly referring to the inner class in the CommandParameter binding with the + sign.
the correct XAML should be:
<Controls1:RadMenuItem Command="{Binding SalesInvoiceViewModel.OpenInvoiceWindowCommand}" CommandParameter="{x:Static local:DebitInvoiceViewModelBase+MessageTokens.SalesInvoice}" Header="Raise a sales invoice"/> 