问题
I am running into the below error the first time my ViewModel is being instantiated by the SimpleIoC. I believe I have setup the container as it should be, but for some reason, I am still getting the below error. Any ideas or assistance would be very much appreciated.
Microsoft.Practices.ServiceLocation.ActivationException was unhandled by user code
HResult=-2146233088
Message=Type not found in cache: Windows.UI.Xaml.Controls.Frame.
Source=GalaSoft.MvvmLight.Extras
StackTrace:
at GalaSoft.MvvmLight.Ioc.SimpleIoc.DoGetService(Type serviceType, String key) in c:\Users\Public\Downloads\CodePlex\MVVMLight\GalaSoft.MvvmLight\GalaSoft.MvvmLight.Extras (NET35)\Ioc\SimpleIoc.cs:line 532
at GalaSoft.MvvmLight.Ioc.SimpleIoc.GetService(Type serviceType) in c:\Users\Public\Downloads\CodePlex\MVVMLight\GalaSoft.MvvmLight\GalaSoft.MvvmLight.Extras (NET35)\Ioc\SimpleIoc.cs:line 768
at GalaSoft.MvvmLight.Ioc.SimpleIoc.MakeInstance[TClass]() in c:\Users\Public\Downloads\CodePlex\MVVMLight\GalaSoft.MvvmLight\GalaSoft.MvvmLight.Extras (NET35)\Ioc\SimpleIoc.cs:line 708
InnerException:
Here are pieces of my code related to this:
ViewModelLocator.cs (Located in my Win8 project)
public class ViewModelLocator
{
/// <summary>
/// Initializes a new instance of the ViewModelLocator class.
/// </summary>
public ViewModelLocator()
{
ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
if (ViewModelBase.IsInDesignModeStatic)
{
// Create design time view services and models
//SimpleIoc.Default.Register<IDataService, DesignDataService>();
}
else
{
// Create run time view services and models
//SimpleIoc.Default.Register<IDataService, DataService>();
SimpleIoc.Default.Register<INavigationService, NavigationService>();
SimpleIoc.Default.Register<IParseService, ParseService>();
SimpleIoc.Default.Register<IServiceHandler, ServiceHandler>();
}
SimpleIoc.Default.Register<MainViewModel>();
SimpleIoc.Default.Register<ActionViewModel>();
}
public MainViewModel MainVM
{
get
{
return ServiceLocator.Current.GetInstance<MainViewModel>();
}
}
public ActionViewModel ActionVM
{
get
{
return ServiceLocator.Current.GetInstance<ActionViewModel>();
}
}
public static void Cleanup()
{
// TODO Clear the ViewModels
}
}
MainViewModel.cs Constructor
public class MainViewModel : ViewModelBase
{
#region Variables
private readonly INavigationService _navigationService;
private readonly IParseService _parseService;
#endregion
/// <summary>
/// Initializes a new instance of the MainViewModel class.
/// </summary>
public MainViewModel(INavigationService navigationService, IParseService parseService)
{
if (IsInDesignMode)
{
// Code runs in Blend --> create design time data.
}
else
{
_navigationService = navigationService;
_parseService = parseService;
BuildCommonData();
}
}
回答1:
I know this is long overdue, but here is the offending code in the implementation of my NavigationService class.
NavigationService class (Before)
public class NavigationService : INavigationService
{
/// <summary>
/// Gets the root frame.
/// </summary>
private Frame RootFrame;
public NavigationService(Frame rootFrame)
{
RootFrame = rootFrame;
}
public event NavigatingCancelEventHandler Navigating;
public void Navigate<T>(object parameter = null)
{
var type = typeof(T);
RootFrame.Navigate(type, parameter);
}
public void Navigate(string type, object parameter = null)
{
RootFrame.Navigate(Type.GetType(type), parameter);
}
public void GoBack()
{
if (RootFrame.CanGoBack)
{
RootFrame.GoBack();
}
}
public void GoForward()
{
if (RootFrame.CanGoForward)
{
RootFrame.GoForward();
}
}
}
I simply took out the constructor, and made the RootFrame private variable a property. Like so:
public class NavigationService : INavigationService
{
/// <summary>
/// Gets the root frame.
/// </summary>
private static Frame RootFrame
{
get { return Window.Current.Content as Frame; }
}
public event NavigatingCancelEventHandler Navigating;
public void Navigate<T>(object parameter = null)
{
var type = typeof(T);
RootFrame.Navigate(type, parameter);
}
public void Navigate(string type, object parameter = null)
{
RootFrame.Navigate(Type.GetType(type), parameter);
}
public void GoBack()
{
if (RootFrame.CanGoBack)
{
RootFrame.GoBack();
}
}
public void GoForward()
{
if (RootFrame.CanGoForward)
{
RootFrame.GoForward();
}
}
}
Simple, I know, but hope it's of some use.
回答2:
I was getting the same error today in my Xamarin
project. The actual error given was "System.Reflection.TargetInvocationException: 'Exception has been thrown by the target of an invocation.'" and then when I look up the InnerException
I could see the actual error, which is Type not found in cache.
It was a silly mistake that I was using DataService
instead of IDataService
for the Constructor Dependency Injection.
public SearchViewModel(DataService dataService, IErrorLoggingService errorLoggingService, IDialogService dialogService, IResourceService resourceService, INavigationService navigationService) {
SearchCommand = new AsyncRelayCommand <SearchFilter>(SearchAsync);
DataService = dataService;
ErrorLoggingService = errorLoggingService;
DialogService = dialogService;
ResourceService = resourceService;
NavigationService = navigationService;
CancelCommand = new RelayCommand(Cancel);
}
And just for your information, this is how I registered my service.
SimpleIoc.Default.Register<IDataService, DataService>();
So the issue was fixed after changing to IDataService
. Hope it helps.
来源:https://stackoverflow.com/questions/17175893/simpleioc-type-not-found-in-cache-windows-ui-xaml-controls-frame