I have a very, very basic MonoGame game (almost just a new project, with just a single image drawn on screen).
In my Game class, I created an instance of StandardKernel. In LoadContent, I bind it to my SpriteBatch:
protected override void LoadContent ()
{
// Create a new SpriteBatch, which can be used to draw textures.
this.SpriteBatch = new SpriteBatch (GraphicsDevice);
// Setup DI bindings
this.Kernel.Bind<SpriteBatch>().ToConstant<SpriteBatch>(this.spriteBatch);
//TODO: use this.Content to load your game content here
}
(The debugger hits this line.) Later, I try to consume it:
protected void LoadSpritesLater() {
var spriteBatch = Game.Instance.Kernel.Get<SpriteBatch>();
}
For some reason, this line always throws a NullReferenceException. I've verified that Game.Instance.Kernel returns me a StandardKernel instance, that I expect.
Oddly, if I replace the Bind call with a setter (eg. this.SpriteBatch = spriteBatch), I can fetch it in LoadSpritesLater and use it without issue.
I checked the Ninject source code and docs to see if the instance is created through Ninject itself (it seems like it isn't). I don't see why this isn't working.
Related
I have the following netcore 2.2 controller method that I am trying to write an xUnit integration test for:
private readonly ISoapSvc _soapSvc;
private readonly IRepositorySvc _repositorySvc;
public SnowConnectorController(ISoapSvc soapSvc, IRepositorySvc repositorySvc)
{
_soapSvc = soapSvc;
_repositorySvc = repositorySvc;
}
[Route("accept")]
[HttpPost]
[Produces("text/xml")]
public async Task<IActionResult> Accept([FromBody] XDocument soapRequest)
{
try
{
var response = new CreateRes
{
Body = new Body
{
Response = new Response
{
Status = "Accepted"
}
}
};
return Ok(response);
}
finally
{
// After the first API call completes
Response.OnCompleted(async () =>
{
// Run the close method
await Close(soapRequest);
});
}
}
The catch block runs and does the things it needs to, then the finally block runs and does things it needs to do after the request in the catch finishes per design.
Close has been both a private method . It started as a public controller method but I don't need to expose it for function so moved it to private method status.
Here's an integration test I started with the intention of just testing the try portion of the code:
[Fact]
public async Task AlwaysReturnAcceptedResponse()
{
// Arrange------
// Build mocks so that we can inject them in our system under tests constructor
var mockSoapSvc = new Mock<ISoapSvc>();
var mockRepositorySvc = new Mock<IRepositorySvc>();
// Build system under test(sut)
var sut = new SnowConnectorController(mockSoapSvc.Object, mockRepositorySvc.Object);
var mockRequest = XDocument.Load("..\\..\\..\\mockRequest.xml");
// Act------
// Form and send test request to test system
var actualResult = await sut.Accept(mockRequest);
var actualValue = actualResult.GetType().GetProperty("Value").GetValue(actualResult);
// Assert------
// The returned object from the method call should be of type CreateRes
Assert.IsType<CreateRes>(actualValue);
}
I am super new to testing... I've been writing the test and feeling my way through the problem. I started by entering the controller method not really knowing where it would go. The test works through the try method, and then an exception is thrown once it hits the delegate in the finally block.
It looks like my test will have to run through to the results of the finally block unless there is a way to tell it to stop with the catch blocks execution?
That's fine, i'm learning, but the problem with that approach for me now is that the HttpResponse's Response.OnCompleted delegate in the finally block returns null when my test is running and I haven't been successful at figuring out what I can do to not make it null - because it is null, it throws this when my unit test is executing -
System.NullReferenceException: 'Object reference not set to an instance of an object.'
*One thought that occurred was that if I was to make the private Close method a public controller method, and then make the Accept method not have the finally block, I could create a third controller method that does the try finally action by running the two controller methods and then just test the individual controller methods that are strung together with the third. However, it doesn't feel right because I would be exposing methods just for the sake of unit testing and I don't need Close to be exposed.
If the above idea is not the right approach, I am wondering what is, and if I just need to test through end to end, how I would get over the null httpresponse?
Any ideas would be appreciated. Thank you, SO community!
EDIT - Updated Test that works after the accepted answer was implemented. Thanks!
[Fact]
public async Task AlwaysReturnAcceptedResponse()
{
// Arrange------
// Build mocks so that we can inject them in our system under tests constructor
var mockSoapSvc = new Mock<ISoapSvc>();
var mockRepositorySvc = new Mock<IRepositorySvc>();
// Build system under test(sut)
var sut = new SnowConnectorController(mockSoapSvc.Object, mockRepositorySvc.Object)
{
// Supply mocked ControllerContext and HttpContext so that finally block doesnt fail test
ControllerContext = new ControllerContext
{
HttpContext = new DefaultHttpContext()
}
};
var mockRequest = XDocument.Load("..\\..\\..\\mockRequest.xml");
// Act------
// Form and send test request to test system
var actualResult = await sut.Accept(mockRequest);
var actualValue = actualResult.GetType().GetProperty("Value").GetValue(actualResult);
// Assert------
// The returned object from the method call should be of type CreateRes
Assert.IsType<CreateRes>(actualValue);
}
Curious what you are doing in the Close method against the input parameter.
Does it have to happen after response is being sent? It might not always happen as you would expect, see here.
Regardless though, during runtime asp.net core runtime sets a lot of properties on the controller including ControllerContext, HttpContext, Request, Response etc.
But those won't be available in unit testing since there is no asp.net core runtime there.
If you really want to test this, you'll have to mock them.
Here is the ControllerBase source code.
As we can see, ControllerBase.Response simply returns ControllerBase.HttpContext.Response, and ControllerBase.HttpContext is a getter from ControllerBase.ControllerContext. This means you'll have to mock a ControllerContext (and the nested HttpContext as well as HttpResponse) and assign it to your controller in the setup phase.
Furthermore, the OnCompleted callback won't get called in unit test either. If you want to unit test that part, you'll have to trigger it manually.
Personally I think it's too much hassle beside the open bug I mentioned above.
I would suggest you move the closing logic (if it's really necessary) to a IDisposable scoped service and handle that in the Dispose instead - assuming it's not a computation heavy operation which can impact the response latency.
I'm not sure what I'm doing wrong, but even though I'm definitely on the UI thread, I'm consistently getting the error " 'The application called an interface that was marshalled for a different thread.'" when constructing Xaml controls in C++.
See the following basic example, which uses a stripped down version of the default C++/WinRT CoreApplication template:
#include "pch.h"
using namespace winrt;
using namespace Windows;
using namespace Windows::ApplicationModel::Core;
using namespace Windows::Foundation::Numerics;
using namespace Windows::UI;
using namespace Windows::UI::Core;
using namespace Windows::UI::Composition;
using namespace Windows::ApplicationModel::Activation;
struct App : implements<App, IFrameworkViewSource, IFrameworkView> {
CompositionTarget m_target{nullptr};
IFrameworkView CreateView() { return *this; }
void Initialize(CoreApplicationView const &) {}
void Load(hstring const &) {}
void Uninitialize() {}
void Run() {
CoreWindow window = CoreWindow::GetForCurrentThread();
winrt::Windows::UI::Xaml::Controls::TextBox textbox; // Crashes here
CoreDispatcher dispatcher = window.Dispatcher();
dispatcher.ProcessEvents(CoreProcessEventsOption::ProcessUntilQuit);
}
void SetWindow(CoreWindow const &) {
Compositor compositor;
ContainerVisual root = compositor.CreateContainerVisual();
m_target = compositor.CreateTargetForCurrentView();
m_target.Root(root);
}
};
int __stdcall wWinMain(HINSTANCE, HINSTANCE, PWSTR, int) { CoreApplication::Run(make<App>()); }
I've tried using window.Dispatcher().HasThreadAccess() to verify that I'm on the correct thread to be making UI calls, and it always returns true.
I've also tried calling RunAsync() from the window's Dispatcher and constructing a Xaml object in a lambda passed to this method, and it still has exactly the same result. HasThreadAccess returns true here too.
Can anyone explain to me where I'm going wrong here? Is constructing Xaml objects not supported in C++?
[edit]
Here's a sample project that reproduces the issue, again based on the default CoreWindow C++/WinRT template:
https://github.com/lyptt/CoreApp1
Turns out the CoreApplication-based template does not support anything from the Xaml namespace, as it's intended more towards providing a thin UWP layer for games, etc.
To get Xaml support you need to use the full template instead, then things magically start to work.
I'm using nServiceBus 5 and have created a number of host endpoints, two of which listen for database changes. (The specifics of how to do this can be found here). The intention is to have a service running in the background which publishes an event message using the Bus when notified to do so by the database listener.
The code which creates the database listener object and handles events is in the Start method, implemented as part of IWantToRunWhenBusStartsAndStops.
So - Is putting the code here likely to cause problems later on, for example if an exception is thrown (yes, I do have try/catch blocks, but I removed them from the sample code for clarity)? What happens when the Start method finishes executing?
Would I be better off with a constructor on my RequestNewQuoteSender class to instantiate the database listener as a class property and not use the Start method at all?
namespace MySample.QuoteRequest
{
public partial class RequestNewQuoteSender : IWantToRunWhenBusStartsAndStops
{
public void Start()
{
var changeListener = new DatabaseChangeListener(_ConnectionString);
// Assign the code within the braces to the DBListener's onChange event
changeListener.OnChange += () =>
{
// code to handle database change event
changeListener.Start(_SQLStatement);
};
// Now everything has been set up.... start it running.
changeListener.Start(_SQLStatement);
}
public void Stop() { LogInfo("Service Bus has stopped"); }
}
}
Your code seems fine to me.
Just a few small things:
Make changeListener a class field, so that it won't be GC (not 100% sure if it would be but just to make sure);
Unsubscribe from OnChange on the Stop() method;
You may also want to have a "lock" around changeListener.Start(_SQLStatement); and the Stop so that there are no racing conditions (I leave that one up to you to figure out if you need it or not);
Does this make sense ?
I'm not sure but from my hours of debugging, this should be the best description of my problem I can give.
I'm creating a WinRT app, there are two pages- Main Page and Details Page. Inside Main Page constructor, I have initialized a listbox. On click of any of the element of listbox, user is taken to the Details page.
I'm just learning all this and design may not be best but here is what I did.
I took a static variable in MainPage.cs, and set it to point to the element which is clicked by the user. Now in the constructor of the Details page, I used this static variable to set the datacontext of Details Page itself.
What flow I'm expecting is:-
MainPage is created first. Listbox is setup.
User will click on any of the element of listbox. Itemclick event handler runs. It will set the static variable (of Mainpage.cs) to hold the infomation which item is clicked and navigate user to the Details page.
In Details page constructor, I have set the datacontext to point to some information based on the value of static variable mentioned in the previous step.
It works for most of the times, but once in like every 5 times, The Details page constructor throws an exception stating the static variable is not initialized yet. Why is Details page's constructor running when I'm starting the app? and why only sometimes? Do I need to set DataContext of Details Page in some other method instead of constructor?
The code is somewhat complex and too much in terms of domain of the problem so I'm avoiding posting it. But if I'm failing to explain the problem please tell, I'll post it keeping it as related as I can.
CODE:-
This is the method called when an item in listbox is clicked--will take user to the Details page.
private void overviewlistbox_Tapped_1(object sender, TappedRoutedEventArgs e)
{
MatchOverview selectedmatch = (sender as ListBox).SelectedItem as MatchOverview;
matchFullDetails = new ObservableCollection<Match>();
foreach (Match m in UpdateController.matchList)
{
if (m.matchDescription == selectedmatch.matchDesc)
{
matchFullDetails.Add(m);
break;
}
}
if(!(matchFullDetails.Count == 0))
this.Frame.Navigate(typeof(Details));
}
This is the constructor for Main Page:-
public static ObservableCollection<Match> matchFullDetails;
public MainPage()
{
matchFullDetails = new ObservableCollection<Match>();
this.InitializeComponent();
UpdateController update = new UpdateController(); // Creating new object will update the overview_list of UpdateController(static list).
overviewlistbox.ItemsSource = UpdateController.overview_list;
}
And this is the code for constructor of details page, where the exception occurs:-
public static ObservableCollection<Match> matchdetails = new ObservableCollection<Match>();
DispatcherTimer dtm_detailspage = null;
public Details()
{
this.InitializeComponent();
matchdetails = MainPage.matchFullDetails; // matchdetails.Last<>() is take because we only need item which is added latest to the collection.
if (matchdetails.Last<Match>().type == "TEST") // Exception is thrown here--Initialization
// error. When I check MainPage.matchFullDetails,
// no data is shown which means its not yet
// initialized. Also the exception is thrown either at
// the start of the app, or when details page is visited. That too once in 4-5 times, not always.
{
matchdetails.Add(matchdetails.First<Match>() as TestMatch);
}
if (matchdetails.Last<Match>().type == "ODI")
{
matchdetails.Add(matchdetails.Last<Match>() as ODIMatch);
}
if (matchdetails.Last<Match>().type == "T20")
{
matchdetails.Add(matchdetails.Last<Match>() as T20Match);
}
}
Exception Screenshot:-
Call Stack data on bug encounter:-
[Cricket Expert.exe!Cricket_Expert.Details.Details() Line 33 + 0x5 bytes
[External Code]
Cricket Expert.exe!Cricket_Expert.Common.SuspensionManager.RestoreFrameNavigationState(Windows.UI.Xaml.Controls.Frame frame) Line 236 + 0x5 bytes
Cricket Expert.exe!Cricket_Expert.Common.SuspensionManager.RestoreAsyn() Line 124 0x8 bytes
Cricket Expert.exe!Cricket_Expert.App.OnLaunched(Windows.ApplicationModel.Activation.LaunchActivatedEventArgs args) Line 74 + 0x5 bytes
[External Code]
MAJOR UPDATE:
I finally found the flaw. If the Details page is still active, and the app is restarted, the problem occurs.
Is there a solution to this problem??
You can pass information on what needs to be displayed on the Details page through the Navigate call and set the DataContext in OnNavigatedTo override to avoid using static variables. Pages don't get created unless you do it specifically e.g. by navigating to one. They might not be recreated if a page has NavigationCacheMode changed from the default (Disabled) so instances of the page can be reused during navigation calls. Ultimately it's hard to say what's wrong but it seems like something in your code and we couldn't help you if you don't share a sample that reproduces the problem.
*EDIT
One way to debug Details being created before MainPage would be to add this code at the beginning of the Details constructor:
if (MainPage.matchFullDetails == null)
{
System.Diagnostics.Debugger.Break();
}
Then look at the Call Stack panel in Visual Studio to see how it gets constructed.
One way to see if matchFullDetails is ever set to null is to search for its assignment (put a cursor on matchFullDetails in Visual Studio code editor and hit Shift+F12).
Another way would be to make matchFullDetails into a property and test it like this:
private static ObservableCollection<Match> _matchFullDetails;
public static ObservableCollection<Match> matchFullDetails
{
get
{
return _matchFullDetails;
}
set
{
if (value == null)
{
System.Diagnostics.Debugger.Break();
}
_matchFullDetails = value;
}
}
*EDIT 2
You can initialize your static property in a static constructor like this:
public static ObservableCollection<Match> matchFullDetails;
static MainPage()
{
matchFullDetails = new ObservableCollection<Match>();
}
public MainPage()
{
this.InitializeComponent();
UpdateController update = new UpdateController(); // Creating new object will update the overview_list of UpdateController(static list).
overviewlistbox.ItemsSource = UpdateController.overview_list;
}
this will prevent the null reference exception but won't fix your problem overall. When your app gets suspended and resumed - you have to restore the full state and it seems like your matchFullDetails collection would need to be serialized and saved to disk when your app gets suspended. Alternatively you might simply ignore the suspension manager call in App.xaml.cs and always start on home page, though that's not a very good experience and I am not sure if it satisfies app certification.
The problem: I'm crashing when I want to render my incoming data which was retrieved asynchronously.
The app starts and displays some dialog boxes using XAML. Once the user fills in their data and clicks the login button, the XAML class has in instance of a worker class that does the HTTP stuff for me (asynchronously using IXMLHTTPRequest2). When the app has successfully logged in to the web server, my .then() block fires and I make a callback to my main xaml class to do some rendering of the assets.
I am always getting crashes in the delegate though (the main XAML class), which leads me to believe that I cannot use this approach (pure virtual class and callbacks) to update my UI. I think I am inadvertently trying to do something illegal from an incorrect thread which is a byproduct of the async calls.
Is there a better or different way that I should be notifying the main XAML class that it is time for it to update it's UI? I am coming from an iOS world where I could use NotificationCenter.
Now, I saw that Microsoft has it's own Delegate type of thing here: http://msdn.microsoft.com/en-us/library/windows/apps/hh755798.aspx
Do you think that if I used this approach instead of my own callbacks that it would no longer crash?
Let me know if you need more clarification or what not.
Here is the jist of the code:
public interface class ISmileServiceEvents
{
public: // required methods
virtual void UpdateUI(bool isValid) abstract;
};
// In main XAML.cpp which inherits from an ISmileServiceEvents
void buttonClick(...){
_myUser->LoginAndGetAssets(txtEmail->Text, txtPass->Password);
}
void UpdateUI(String^ data) // implements ISmileServiceEvents
{
// This is where I would render my assets if I could.
// Cannot legally do much here. Always crashes.
// Follow the rest of the code to get here.
}
// In MyUser.cpp
void LoginAndGetAssets(String^ email, String^ password){
Uri^ uri = ref new URI(MY_SERVER + "login.json");
String^ inJSON = "some json input data here"; // serialized email and password with other data
// make the HTTP request to login, then notify XAML that it has data to render.
_myService->HTTPPostAsync(uri, json).then([](String^ outputJson){
String^ assets = MyParser::Parse(outputJSON);
// The Login has returned and we have our json output data
if(_delegate)
{
_delegate->UpdateUI(assets);
}
});
}
// In MyService.cpp
task<String^> MyService::HTTPPostAsync(Uri^ uri, String^ json)
{
return _httpRequest.PostAsync(uri,
json->Data(),
_cancellationTokenSource.get_token()).then([this](task<std::wstring> response)
{
try
{
if(_httpRequest.GetStatusCode() != 200) SM_LOG_WARNING("Status code=", _httpRequest.GetStatusCode());
String^ j = ref new String(response.get().c_str());
return j;
}
catch (Exception^ ex) .......;
return ref new String(L"");
}, task_continuation_context::use_current());
}
Edit: BTW, the error I get when I go to update the UI is:
"An invalid parameter was passed to a function that considers invalid parameters fatal."
In this case I am just trying to execute in my callback is
txtBox->Text = data;
It appears you are updating the UI thread from the wrong context. You can use task_continuation_context::use_arbitrary() to allow you to update the UI. See the "Controlling the Execution Thread" example in this document (the discussion of marshaling is at the bottom).
So, it turns out that when you have a continuation, if you don't specify a context after the lambda function, that it defaults to use_arbitrary(). This is in contradiction to what I learned in an MS video.
However by adding use_currrent() to all of the .then blocks that have anything to do with the GUI, my error goes away and everything is able to render properly.
My GUI calls a service which generates some tasks and then calls to an HTTP class that does asynchronous stuff too. Way back in the HTTP classes I use use_arbitrary() so that it can run on secondary threads. This works fine. Just be sure to use use_current() on anything that has to do with the GUI.
Now that you have my answer, if you look at the original code you will see that it already contains use_current(). This is true, but I left out a wrapping function for simplicity of the example. That is where I needed to add use_current().