綁定枚舉到MVVM光RelayCommand <T> CommandParameter

Question

我試圖在XAML命令參數綁定爲一個RelayCommand <MessageTokens>如下，其中MessageTokens是一個枚舉

public ICommand OpenInvoiceWindowCommand 
     { 
      get 
      { 
       return _openInvoiceWindowCommand ?? 
         (_openInvoiceWindowCommand = new RelayCommand<MessageTokens>(OpenInvoiceWindow, prm => CanExecuteOpenInvoiceWindowCommand)); 
      } 
     } 

的XAML是：

<Controls1:RadMenuItem Command="{Binding SupplierInvoiceViewModel.OpenInvoiceWindowCommand}" CommandParameter="{Binding Source={x:Type ShipmentDetails:DebitInvoiceViewModelBase}, Path=MessageTokens.SupplierInvoice}" Header="Register a supplier's invoice"/> 

使用Telerik的RadGridView代碼崩潰與

 
    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) 

等

如果我將參數更改爲RelayCommand <string>而不是RelayCommand <MessageTokens>代碼運行良好。

我不喜歡這樣做，因爲我失去了強烈輸入我的參數的所有好處。

我懷疑我沒有在XAML中正確聲明枚舉。我試過

CommandParameter = "<fullpath>..MessageTokens.SupplierInvoice>" 

但在MVVMLight中給出了InvalidCastException。

有沒有人有任何建議？

非常感謝 傑里米

編輯與解決方案

的問題是，因爲我沒有正確指在CommandParameter內部類的+號綁定。

正確的XAML應該是：

<Controls1:RadMenuItem Command="{Binding SalesInvoiceViewModel.OpenInvoiceWindowCommand}" CommandParameter="{x:Static local:DebitInvoiceViewModelBase+MessageTokens.SalesInvoice}" Header="Raise a sales invoice"/> 

Answer 1

您可能wnat來看看這篇文章解釋瞭如何通過一個枚舉值作爲commandparameter：Passing an enum value as command parameter from XAML。