I'm working on an ASP.NET MVC 5, I want to log all exceptions that occurs in the controller's actions.
To accomplish this I'm creating a custom aspect using PostSharp (in a dll), there I've already created the code to write the log files, now I want that the aspect can be controller-wide (do not want to apply it by hand to all methods).
The aspect's code looks like this:
using System;
using PostSharp.Aspects;
namespace Banlinea.Ceb.Domain.Aspects
{
public class LogException : OnExceptionAspect
{
public LogException()
{
ApplyToStateMachine = true;
}
public override void OnException(MethodExecutionArgs args)
{
//Code for logging the exception
args.FlowBehavior = FlowBehavior.ThrowException;
}
}
}
Now, what I want in my controller is to do something like this:
[LogException]
public class MyController : Controller
{
public ActionResult Index()
{
return View();
}
public ActionResult Other()
{
return View();
}
public ActionResult Another()
{
return View();
}
}
Just decorate the class, How can I do that?
you can do this byimplementing IAspectProvider
http://doc.postsharp.net/iaspectprovider
public IEnumerable<AspectInstance> ProvideAspects(object targetElement)
{
Type type = (Type)targetElement;
return type.GetMethods().Select(
m => return new AspectInstance(targetElement, new LogException()) );
}
You can apply PostSharp aspects across your codebase by using a feature called attribute multicasting.
For example, when you apply a method-level aspect on a class level or assembly level, then it is automatically copied to all the methods in the corresponding class or assembly. You can additionally filter the target elements by setting the attribute properties, such as AttributeTargetTypes, AttributeTargetMemberAttributes etc.
The sample code from your question should actually work as you expect.
Related
I have a Blazor (Server) application which runs perfectly fine, and which adheres to all rules set by Microsoft.CodeAnalysis.FxCopAnalyzers and StyleCop.Analyzers.
A heavily cut-down razor page is as follows:
#inherits OwningComponentBase<MyService>
#inject IModalService ModalService
#inject IJSRuntime JSRuntime
// UI code
#code
{
private readonly CancellationTokenSource TokenSource = new CancellationTokenSource();
ElementReference myElementReferenceName;
protected override async Task OnAfterRenderAsync(bool firstRender)
{
await this.myElementReferenceName.FocusAsync(this.JSRuntime);
}
protected override async Task OnInitializedAsync()
{
....
}
public void Dispose()
{
this.TokenSource.Cancel();
}
protected void ShowModalEdit(object someObject)
{
.....
Modal.Show<MyPage>("Edit", parameters);
}
}
Note#1: I used #inherits OwningComponentBase<MyService> based on Daniel Roth's suggestion
Note#2: I am using the Chris Sainty's Modal component component
However, when I try to move all the code from the #code {...} section to a"Code Behind" partial class ("MyPage.razor.cs"), then I run into the following errors....
'MyPage' does not contain a definition for 'Service' and no accessible
extension method 'Service' accepting .....
'MyPage.OnAfterRenderAsync(bool)': no suitable method found to override
'MyPage.OnInitializedAsync()': no suitable method found to override
The type 'MyPage' cannot be used as type parameter 'T' in the generic
type or method 'IModalService.Show(string, ModalParameters,
ModalOptions)'. There is no implicit reference conversion from
'MyPage' to 'Microsoft.AspNetCore.Components.ComponentBase'.
Suggestions?
Your MyPage.razor.cs should inherit from ComponentBase class and your Mypage.razor should inherit from MyPage.razor.cs.
In your "code-behind" class you should use [Inject] attribute for every service you are injecting and make them at least protected properties to be able to use them in your razor components.
Below is an example from one of my testing apps, please note this uses .net-core 3.0, in 3.1 you can use partial classes.
Index.razor
#page "/"
#inherits IndexViewModel
<div class="row">
<div class="col-md">
#if (users == null)
{
<p><em>Hang on while we are getting data...</em></p>
}
else
{
<table class="table">
<thead>
<tr>
<th class="text-danger">Id</th>
<th class="text-danger">Username</th>
<th class="text-danger">Email</th>
<th class="text-danger">FirstName</th>
<th class="text-danger">LastName</th>
</tr>
</thead>
<tbody>
#foreach (var user in users)
{
<tr>
<td>#user.Id</td>
<td>#user.Username</td>
<td>#user.Email</td>
<td>#user.FirstName</td>
<td>#user.LastName</td>
</tr>
}
</tbody>
</table>
}
</div>
</div>
IndexViewModel.cs
public class IndexViewModel : ComponentBase, IDisposable
{
#region Private Members
private readonly CancellationTokenSource cts = new CancellationTokenSource();
private bool disposedValue = false; // To detect redundant calls
[Inject]
private IToastService ToastService { get; set; }
#endregion
#region Protected Members
protected List<User> users;
[Inject] IUsersService UsersService { get; set; }
protected string ErrorMessage { get; set; }
#endregion
#region Constructor
public IndexViewModel()
{
users = new List<User>();
}
#endregion
#region Public Methods
#endregion
#region Private Methods
protected override async Task OnInitializedAsync()
{
await GetUsers().ConfigureAwait(false);
}
private async Task GetUsers()
{
try
{
await foreach (var user in UsersService.GetAllUsers(cts.Token))
{
users.Add(user);
StateHasChanged();
}
}
catch (OperationCanceledException)
{
ShowErrorMessage($"{ nameof(GetUsers) } was canceled at user's request.", "Canceled");
}
catch (Exception ex)
{
// TODO: Log the exception and filter the exception messages which are displayed to users.
ShowErrorMessage(ex.Message);
}
}
private void ShowErrorMessage(string message, string heading ="")
{
//ErrorMessage = message;
//StateHasChanged();
ToastService.ShowError(message, heading);
}
private void ShowSuccessMessage(string message, string heading = "")
{
ToastService.ShowSuccess(message, heading);
}
protected void Cancel()
{
cts.Cancel();
}
#endregion
#region IDisposable Support
protected virtual void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing)
{
cts.Dispose();
}
disposedValue = true;
}
}
public void Dispose()
{
Dispose(true);
// TODO: uncomment the following line if the finalizer is overridden above.
// GC.SuppressFinalize(this);
}
#endregion
}
TLDR
Make sure the namespace in your razor.cs file is correct
Longer explanation
In my case, I got this error when I put the class in the wrong namespace. The page.razor.cs file was in the same directory as the page.razor file and it contained a partial class as accepted by the October 2019 update.
However, even though the files were located in path/to/dir, page.razor.cs had a namespace of path.to.another.dir, which led to this error being thrown. Simply changing the namespace to path.to.dir fixed this error for me!
Came across this error when I used partial class approach and I was trying to scaffold Identity. I changed to base class aprroach it was resolved.
partial class I was using
after adding a component say MyComponent, add a class MyComponent.razor.cs
for injecting services
use
[Inject]
public BuildingServices Services { get; set; }
for base class approach
after adding a component say MyComponent, add a class MyComponent.razor.cs
change the class name and make it inherit from componentBase
MyComponentBase : ComponentBase
and place this at the top of MyComponent.razor
#inherits MyComponentBase
Use protected keyword to make your methods accessible
All the above points are very true. FWIW, and just to add a weird thing that I was finding with this issue; I could not get that error to go away. Everything was declared as it should be. Once you have ruled out all potential coding issues, I have found exiting VS, coming back in, and rebuilding clears it up. It is almost like VS just will not let go of that error.
It took two days of cleaning, rebuilding, ... and it turned out to be a cut and paste error. I copied the razor file from another, similar class, and left this at the top by mistake:
#inject Microsoft.Extensions.Localization.IStringLocalizer<Person> localizer
'Person' was the wrong class, it wasn't defined by any of the include statements. For some strange reason the only error was "OnInitialized() No method found to override."
I found this when upgrading to 6.0. I had to switch from using base classes to using partial classes!
Use Case
A separated template engine that doesn't interfere in any way with normal Razor operation in an AspNetCore (2.X) web app.
Problem
Whilst trying to implement the above, I've created a whole bunch of derived wrapper classes based on RazorViewEngine, RazorViewCompilerProvider, DefaultRazorPageFactoryProvider, DefaultRazorViewEngineFileProviderAccessor and RazorViewEngineOptions in an effort that these can be registered with DI and injected whilst not having side affects in the normal Razor code path. I've succeeded except for one annoying issue, whereby I still need to configure my custom FileProvider (TemplateRepository) within the normal RazorViewEngineOptions rather than my wrapper class.
e.g. In the below code from Startup.cs, even though the file provider is specified in my custom Options object, and that is what is injected into the wrapper classes, the TemplateRepository is not called for a View request unless the second service.Configure is also included (using RazorViewEngineOptions).
services.Configure<TemplateOptions>(options =>
{
options.ViewLocationExpanders.Add(new TemplateNameExpander());
options.ViewLocationFormats.Add("{0}");
options.AreaViewLocationFormats.Add("{0}");
options.FileProviders.Clear();
options.FileProviders.Add(new TemplateRepository(new SqlConnectionFactory(configuration)));
});
services.Configure<RazorViewEngineOptions>(
options =>
{
options.FileProviders.Add(new TemplateRepository(new SqlConnectionFactory(configuration)));
});
This would suggest to me that somewhere in the RazorViewEngine dependency tree the RazorViewEngineOptions is being injected somewhere, but I cannot find it.
Full Source # GitHub
It seems that you have defined your custom RazorViewEngine but you do not tell MVC to use it.
Try to add below codes to add TemplateRazorEngine to MVC view engine.
services.Configure<TemplateOptions>(options =>
{
options.ViewLocationExpanders.Add(new TemplateNameExpander());
options.ViewLocationFormats.Add("{0}");
options.AreaViewLocationFormats.Add("{0}");
options.FileProviders.Clear();
options.FileProviders.Add(new TemplateRepository(new SqlConnectionFactory(configuration)));
});
services.Configure<MvcViewOptions>(options => {
var engine = services.BuildServiceProvider().GetRequiredService<TemplateRazorEngine>();
options.ViewEngines.Add(engine);
});
Late to the party but maybe you will use this in the future. I've also tried a lot of options and in the end I came to the conclusion that child containers would solve my particular issue. Unfortunately the AspNetCore container doesn't support them so I had to implement something quick that might not work in your case. Another option would be to use StructureMap or any other container that supports this functionality.
public class ChildServiceProvider : IServiceProvider, IDisposable
{
private readonly IServiceProvider _child;
private readonly IServiceProvider _parent;
public ChildServiceProvider(IServiceProvider parent, IServiceProvider child)
{
_parent = parent;
_child = child;
}
public ChildServiceProvider(IServiceProvider parent, IServiceCollection services)
{
_parent = parent;
_child = services.BuildServiceProvider();
}
public void Dispose()
{
(_child as IDisposable)?.Dispose();
}
public object GetService(Type serviceType)
{
return _child.GetService(serviceType) ?? _parent.GetService(serviceType);
}
}
And this is how I used it
public class Startup : IStartup
{
public IServiceProvider ChildServiceProvider { get; set; }
IServiceProvider IStartup.ConfigureServices(IServiceCollection services)
{
// Define a wrapper for the RazorViewEngine and it as a singleton
services.AddSingleton<CustomRazorEngine>(serviceProvider =>
{
// get the RazorViewEngine from the childContainer
var razorViewEngine = ChildServiceProvider.GetRequiredService<IRazorViewEngine>();
return new CustomRazorEngine(razorViewEngine);
});
return services.BuildServiceProvider();
}
public void Configure(IApplicationBuilder app)
{
ChildServiceProvider = CreateChildServiceProvider(app);
app.UseMvc();
}
IServiceProvider CreateChildServiceProvider(IApplicationBuilder parentApp)
{
// create the child container from the parentApp and register
// the custom RazorViewEngineOptions that you need for the isolated templating engine
// and whatever custom services that you need
var server = parentApp.ApplicationServices.GetRequiredService<IServer>();
var webHost = WebHost.CreateDefaultBuilder()
.ConfigureServices(services =>
{
services.AddOptions();
services.Configure<RazorViewEngineOptions>(opts =>
{
opts.FileProviders.Clear();
opts.FileProviders.Add(new CustomFileProvider());
});
services.AddMvc();
})
.Build();
return new ChildServiceProvider(parentApp.ApplicationServices, webHost.Services);
}
}
And the custom classes that you would need to implement
public class CustomFileProvider : IFileProvider
{
}
public class CustomRazorEngine
{
private readonly IRazorViewEngine _razorViewEngine;
public CustomRazorEngine(IRazorViewEngine razorViewEngine)
{
_razorViewEngine = razorViewEngine;
}
}
This was tested with dotnet 2.2 but haven't thoroughly tested it to be 100% that there are no performance issues or other hidden ones.
Also would be curious to know if you found another solution :)
I'm currently diving into the world of Xamarain with the MvvmCross framework. In my current project I want to make use of a MVVM base ViewModel to be able to reuse some of my code in other ViewModels.
When trying to implement this I've ran into a problem when using the MvxViewModel which supports passing parameters between navigation.
public abstract class BaseViewModel<TParameter> : MvxViewModel, IMvxViewModel<TParameter> where TParameter : class
{
protected readonly IMvxNavigationService _navigationService;
public BaseViewModel(IMvxNavigationService navigationService)
{
_navigationService = navigationService;
}
public new abstract Task Initialize(TParameter parameter);
}
This way I'm able to use the BaseViewModel as following.
public class ExampleViewModel : BaseViewModel<ExampleParameters>
{
private ExampleParameters _parameter;
public ExampleViewModel(IMvxNavigationService navigationService) : base(navigationService)
{
}
public override Task Initialize(ExampleParameters parameter)
{
return Task.Run(() => { _parameter = parameter; });
}
}
In this situation I think this is a pretty good solution. The ExampleViewModel even tells me I need to implement the Initialize Task when I've forgotten.
Still this solution is not great in every situation. When I have ViewModel that doesn't require the passing of parameters I still need to specify a parameters object and implement the Initialize method.
public class ParameterlessViewModel : BaseViewModel<object>
{
public ParameterlessViewModel(IMvxNavigationService navigationService) : base(navigationService)
{
}
public override Task Initialize(object parameter)
{
return Task.Run(() => { });
}
}
When removing the abstract method from the BaseViewModel I wont need to implement the Initialize method but then I won't be forced to implement it when I'm creating a ViewModel that requires the passing of parameters.
The above solution is workable but I'm curious if anyone ran into this same problem and maybe has a better solution? One which is good in both situations without having to setup two BaseViewModel classes.
Kind regards,
Jop Middelkamp
The documentation for this states: https://www.mvvmcross.com/documentation/fundamentals/navigation
If you have a BaseViewModel you might not be able to inherit MvxViewModel<TParameter> or MvxViewModel<TParameter, TResult> because you already have the BaseViewModel as base class. In this case you can implement the following interface:
IMvxViewModel<TParameter>, IMvxViewModelResult<TResult> or IMvxViewModel<TParameter, TResult>
In case you use TResult you can just copy the source code into your viewmodel:
public override TaskCompletionSource<object> CloseCompletionSource { get; set; }
public override void ViewDestroy()
{
if (CloseCompletionSource != null && !CloseCompletionSource.Task.IsCompleted && !CloseCompletionSource.Task.IsFaulted)
CloseCompletionSource?.TrySetCanceled();
base.ViewDestroy();
}
Do we do the add the Interface IMvxViewModel in the base class or the device class, can you give a simple example
In this case you can implement the following interface:
IMvxViewModel<TParameter>, IMvxViewModelResult<TResult> or IMvxViewModel<TParameter, TResult>
in a main viewmodel where i collect data from another viewmodels, I created in summary two or three public Init methods with different signatures. When i navigate back to the base viewmodel from the other viewmodels with ShowViewModel, I awaited that the right Init method will be executed, but this don't happen. Regarding the greet practical documentation here:
http://slodge.blogspot.ch/2013/03/v3-new-viewmodel-lifecycle.html
This should be work :-/.
I will explain this with some code.
My main view model is e.g.:
public class MainViewModel : MvxViewModel
{
MainViewModel() {}
public class ParameterFirst
{
public string Id { get; set; }
}
public class ParameterSecond
{
public string Id { get; set; }
}
public class ParameterSecond
{
public string Id { get; set; }
}
public class ParameterThird
{
public string Id { get; set; }
}
public void Init(ParameterFirst objFirst)
{
//do something
}
public void Init(ParameterSecond objSecond)
{
//do something
}
public void Init(ParameterThird objThird)
{
//do something
}
}
Then I will navigate from another viewmodel and await that the right Init method will be executed:
public class CollectData_ONE_ViewModel : MvxViewModel
{
CollectData_ONE_ViewModel() {}
public void DidWork()
{
//Hopefully the Init method with argument ParameterFirst should be called
base.ShowViewModel<MainViewModel>(new MainViewModel.ParameterFirst { Id = "11" });
}
}
next here the second viewmodel
public class CollectData_SECOND_ViewModel : MvxViewModel
{
CollectData_SECOND_ViewModel() {}
public void DidWork()
{
//Hopefully the Init method with argument ParameterFirst should be called
base.ShowViewModel<MainViewModel>(new MainViewModel.ParameterSecond { Id = "22" });
}
}
and the third viewmodel
public class CollectData_THIRD_ViewModel : MvxViewModel
{
CollectData_THIRD_ViewModel() {}
public void DidWork()
{
//Hopefully the Init method with argument ParameterFirst should be called
base.ShowViewModel<MainViewModel>(new MainViewModel.ParameterThird { Id = "33" });
}
}
In my code, each time the First Init method is called, I'm really at the end and don't have further ideas :) Did anyone here experienced the same issue? Or do anyone here have another Idea to collect data to the main viewmodel in an elegant way? Thanks a lot in advance for reading :)
The Init mechanism in MvvmCross is deliberately lightweight. If you declare multiple methods, all of them will be called - this is by design. Also if some of the Init parameter objects were to share properties then these would clash - see Custom types in Navigation parameters in v3
As it says in the blog post you reference "generally you will probably only want to use one within your application" - so I'd recommend refactoring to a single navigation parameter object and using your own ViewModel-based logic to decide how your ViewModel should initialise.
If you really do need three Init methods called in three different situations, then you can easily pack and unpack your own parameter objects using a custom method (possibly in a BaseViewModel class) like in https://stackoverflow.com/a/19059938/373321
In Junit 4 we add test suites using annotations as mentioned below:
#RunWith(Suite.class)
#SuiteClasses({
A.class, B.class })
public class MyTestsuite
{
}
My query is, do we have any way to specify condition to decide which classes i wanted to include in the #SuiteClasses. For example; lets say in the above code, if i wanted to class A if some particular condition is true, else i don't want to add it to #SuiteClasses.
In junit 3.8 we do it using suite() method like mentioned below:
public class MyTestsuite extends TestCase
{
public static Test suite()
{
TestSuite suite = new TestSuite();
if(some_condition_true)
{
suite.addTest(A.suite);
}
suite.addTest(B.suite);
return suite;
}
}
Is there any way we can achieve this using junit 4?
Extend Suite:
#RunWith(MySuite.class)//Customized
#SuiteClasses({
A.class, B.class })
public class MyTestsuite
{}
Define MySuite:
public class MySuite extends Suite {
public MySuite(Class<?> klass, RunnerBuilder builder)
throws InitializationError {
super(klass, builder);
try {
filter(new Filter() {
#Override public boolean shouldRun(Description description) {
return some_condition_true? true : false;
}
#Override
public String describe() {
return "...";
}
});
} catch (NoTestsRemainException e) {
System.out.println("Hey, all test cases are not satisfied your condition.");
}
}
}
plus: Although it can work, I recommend keep the test case simple. It is hard to maintain complex thing.
Shengyuan answer will work.
Another option is to always add the test class, but have an assumeTrue(condition) in your class that will decide when it should run and when it doesn't make sense.
(I like that approach better when the condition is related to test prerequisites: the test itself is the best place to know if it should run or not).