我在我的WPF应用程序中使用PRISM 5。我的应用程序的Shell视图有两个区域,称之为A和B。区域A包含一个弹出窗口(使用PRISM 5互动特性显示弹出窗口)。
当我在视图构造函数中创建弹出窗口视图模型的实例时,应用程序正常工作。
正常工作代码
public PopupView()
{
InitializeComponent();
this.DataContext = new PopupViewModel(); // Working code
}
但是当我尝试使用依赖注入创建视图模型实例时,应用程序会在父视图(View A)的InitializeComponent();
处崩溃。
依赖注入未起作用的代码
public PopupView(PopupViewModel viewModel)
{
InitializeComponent(); // Failing in AView initialze
// before reaching here
this.DataContext = viewModel;
}
在模块/引导程序中注册视图模型
container.RegisterType<AViewModel>();
错误发生了
发生了空引用异常
堆栈跟踪(已编辑,仅供本问题使用)
at System.DefaultBinder.BindToMethod(BindingFlags bindingAttr, MethodBase[] match, Object[]& args, ParameterModifier[] modifiers, CultureInfo cultureInfo, String[] names, Object& state)
at MS.Internal.Xaml.Runtime.DynamicMethodRuntime.CreateInstanceWithCtor(Type type, Object[] args)
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.CreateInstance(XamlType xamlType, Object[] args)
at MS.Internal.Xaml.Runtime.PartialTrustTolerantRuntime.CreateInstance(XamlType xamlType, Object[] args)
at System.Xaml.XamlObjectWriter.Logic_CreateAndAssignToParentStart(ObjectWriterContext ctx)
at System.Xaml.XamlObjectWriter.WriteEndObject()
at System.Windows.Markup.WpfXamlLoader.TransformNodes(XamlReader xamlReader, XamlObjectWriter xamlWriter, Boolean onlyLoadOneNode, Boolean skipJournaledProperties, Boolean shouldPassLineNumberInfo, IXamlLineInfo xamlLineInfo, IXamlLineInfoConsumer xamlLineInfoConsumer, XamlContextStack`1 stack, IStyleConnector styleConnector)
at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
at MyNamespace.AView.InitializeComponent() in e:\xxx\xxxxx\xxx\AView.xaml:line 1
at MyNamespace.AView..ctor(AViewModel viewModel) in e:\xxx\xxxxx\xxx\AView.xaml.cs:line 18
AViewModel(已编辑以避免特定项目信息)
public class ItemSelectionNotification : Confirmation
{
//This class includes properties related to my project
}
public class AViewModel
{
public InteractionRequest<ItemSelectionNotification> ItemSelectionRequest { get; private set; }
public AViewModel(EventAggregator eventAggregator,IUnityContainer container)
{
this.eventAggregator = eventAggregator;
this.container = container;
ItemSelectionRequest = new InteractionRequest<ItemSelectionNotification>();
SettingsCommand = new DelegateCommand(OnClickSetting); //Command for settings button click
}
//Button click handling
public void OnClickSetting()
{
var notification = new ItemSelectionNotification()
{
Title = "Items"
};
this.ItemSelectionRequest.Raise(notification,OnSaveCallback);
}
private void OnSaveCallback(PropertySelectionNotification returned)
{
}
}