A funny feature that I've encountered recently. It's not something most people would find useful, but it helps tremendously with tracing and debugging what is going on. It's easy, just add .TagWith(someString) to your LINQ query and it will generate comments in SQL. More details here: Query tags. One of the best things you could do in software is unit testing. There are tons of articles, including mine, explaining why people should take the time to write code in a way that makes it easily split into independent parts that then can automatically tested. The part that is painful comes afterwards, when you've written your software, put it in production and you are furiously working for the second iteration. Traditionally, unit tests are great for refactorings, but when you are changing the existing code, you need not only to "fix" the tests, but also cover the new scenarios, allow for changes and expansions of existing ones.
Long story short, you will not be able to be confident your test suite covers the code as it changes until you can compute something called Code Coverage, or the amount of your code that is traversed during unit tests. Mind you, this is not a measure of how much of your functionality is covered, only the lines of code. In Visual Studio, they did a dirty deed and restricted the functionality to the Enterprise edition. But I am here to tell you that in .NET Core (and possibly for Framework, too, but I haven't tested it) it's very easy to have all the functionality and more even for the free version of Visual Studio.
These are the steps you have to take:
@ECHO OFF
REM You need to add references to the nuget packages ReportGenerator and coverlet.msbuild
IF NOT EXIST "..\..\packages\reportgenerator" (
ECHO You need to install the ReportGenerator by Daniel Palme nuget
EXIT 1
)
IF NOT EXIST "..\..\packages\coverlet.msbuild" (
ECHO You need to install the coverlet.msbuild by tonerdo nuget
EXIT 1
)
IF EXIST "bin/CoverageReport" RMDIR /Q /S "bin/CoverageReport"
IF EXIST "bin/coverage.opencover.xml" DEL /F "bin/coverage.opencover.xml"
dotnet test "Primus.Core.UnitTests.csproj" --collect:"code coverage" /p:CollectCoverage=true /p:CoverletOutputFormat=\"opencover\" /p:CoverletOutput=\"bin/coverage\"
for /f "tokens=*" %%a in ('dir ..\..\packages\reportgenerator /b /od') do set newest=%%a
"..\..\packages\reportgenerator\%newest%\tools\netcoreapp3.0\ReportGenerator.exe" "-reports:bin\coverage.opencover.xml" "-targetdir:bin/CoverageReport" "-assemblyfilters:-*.DAL*" "-filefilters:-*ServiceCollectionExtensions.cs"
start "Primus Plumbing Code Coverage Report" "bin/CoverageReport/index.htm"
Notes about the batch file:
Running the batch should start dotnet test and save the result in both coverage.opencover.xml and also some files in the TestResults folder. Then ReportGenerator will generate an html file with the coverage report that will get open at the end. However, if you followed the optional answer, now you are able to open the files in TestResults and see what parts of your code are covered when opened in the Visual Studio editor! I found this less useful than the HTML report, but some of my colleagues liked the option.
I hope this helps you.
There is one basic functionality of all main programming languages: throwing exceptions. Determining in code that something is wrong, one throws an exception of a certain type with extra messages and values. The problem this solves is breaking an execution flow that has entered an invalid state and being aware of what happened. Traditionally, errors are then caught in higher levels of the application and decisions are made: ignore the error, log it, encapsulate it into another exception with extra information, throw it as it is after some cleanup, etc.var exception = new ArgumentException("{localVariable} is null or empty");
var builder = new ExceptionBuilder(ex, logger)
.SetError(Error.EmptyValue)
.SetName(nameof(localVariable))
.AddValue(localVariable)
.SetOrigin("Getting the localVariable in order to save the world")
.SetMessageId(Messages.EmptyWorldNameWhenTryingToSaveIt)
.ShouldBeIgnored();
throw builder.Build(); // this also logs and returns an exception of a type the builder decides relevant
throw new ArgumentException("{localVariable} is null or empty")
.SetError(Error.EmptyValue)
.SetName(nameof(localVariable))
.AddValue(localVariable)
.SetOrigin("Getting the localVariable in order to save the world")
.SetMessageId(Messages.EmptyWorldNameWhenTryingToSaveIt)
.ShouldBeIgnored()
.Build();
/// <summary>
/// Add data to exceptions, then build a Custom exception
/// using registered <see cref="IExceptionBuildHandler"/> and optional logging
/// </summary>
public static class ExceptionBuilder
{
private const string CustomPrefix = "Custom.";
private static readonly List<IExceptionBuildHandler> _handlers = new List<IExceptionBuildHandler>();
private static ICustomLogger _logger;
#region Extended Data
/// <summary>
/// Attaches a custom <see cref="Error"/> to the exception
/// </summary>
/// <param name="ex"></param>
/// <param name="error"></param>
/// <returns></returns>
public static Exception SetError(this Exception ex, Error error)
{
_logger?.LogTrace($"Setting error {error} in exception {ex}");
return ex.SetData(nameof(Error), error);
}
/// <summary>
/// Attaches an object as the exception origin to the exception
/// </summary>
/// <param name="ex"></param>
/// <param name="origin"></param>
/// <returns></returns>
public static Exception SetOrigin(this Exception ex, object origin)
{
_logger?.LogTrace($"Setting exception origin {origin} in exception {ex}");
return ex.SetData("origin", origin);
}
/// <summary>
/// Attaches a name parameter to the exception
/// </summary>
/// <param name="ex"></param>
/// <param name="name"></param>
/// <returns></returns>
public static Exception SetName(this Exception ex, string name)
{
_logger?.LogTrace($"Setting exception name {name} in exception {ex}");
return ex.SetData("name", name);
}
/// <summary>
/// Declare an exception as not breaking the execution flow.
/// Implement catch blocks for exceptions like this to support this scenario.
/// </summary>
/// <param name="ex"></param>
/// <returns></returns>
public static Exception TryToIgnore(this Exception ex)
{
_logger?.LogTrace($"Declaring exception {ex} as not breaking execution flow");
return ex.SetData("tryToIgnore", true);
}
/// <summary>
/// True if this exception is declared as not breaking execution flow
/// </summary>
/// <param name="ex"></param>
/// <returns></returns>
public static bool ShouldBeIgnored(this Exception ex)
{
return object.Equals(ex.GetData("tryToIgnore"), true);
}
/// <summary>
/// Attaches a type to the exception
/// </summary>
/// <param name="ex"></param>
/// <param name="type"></param>
/// <returns></returns>
public static Exception AddType(this Exception ex, Type type)
{
_logger?.LogTrace($"Attaching type {type} in exception {ex}");
return ex.AddData("types", type);
}
/// <summary>
/// Attaches a value to the exception
/// </summary>
/// <param name="ex"></param>
/// <param name="value"></param>
/// <returns></returns>
public static Exception AddValue(this Exception ex, object value)
{
_logger?.LogTrace($"Attaching type {value} in exception {ex}");
return ex.AddData("values", value);
}
/// <summary>
/// Gets data from exception based on key.
/// Returns null if not found.
/// </summary>
/// <param name="ex"></param>
/// <param name="key"></param>
/// <returns></returns>
public static object GetData(this Exception ex, string key)
{
key = $"{CustomPrefix}{key}";
if (ex.Data?.Contains(key)!=true)
{
return null;
}
return ex.Data[key];
}
/// <summary>
/// Attaches an object to exception data replacing any previous one with the same key
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="ex"></param>
/// <param name="key"></param>
/// <param name="value"></param>
/// <returns></returns>
public static Exception SetData<T>(this Exception ex, string key, T value)
{
key = $"{CustomPrefix}{key}";
var result = ex.AsCustomException();
ex.Data[key] = value;
return result;
}
/// <summary>
/// Adds an object to a list that resides in the exception data at the given key
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="ex"></param>
/// <param name="key"></param>
/// <param name="value"></param>
/// <returns></returns>
public static Exception AddData<T>(this Exception ex, string key, T value)
{
key = $"{CustomPrefix}{key}";
var result = ex.AsCustomException();
var alreadyExists = ex.Data.Contains(key);
if (!alreadyExists || !(ex.Data[key] is List<T> list))
{
if (alreadyExists)
{
_logger?.LogWarning($"Overwriting data {ex.Data[key]} with key {key} with an empty list of {typeof(T).Name} in exception {ex}.");
_logger?.LogWarning($"Are you using Add* and Set* builder methods at the same time or adding objects of different types?");
}
list = new List<T>();
ex.Data[key] = list;
}
lock (list)
{
list.Add(value);
}
return result;
}
#endregion Extended Data
/// <summary>
/// Builds the exception from the Data and the provided base exception
/// </summary>
/// <param name="ex"></param>
/// <returns></returns>
public static CustomException Build(this Exception ex)
{
var CustomException = ex.AsCustomException();
lock (_handlers)
{
for (var index = _handlers.Count - 1; index >= 0; index--)
{
var handler = _handlers[index];
var result = handler.Build(CustomException, _logger);
if (result != null)
{
CustomException = result.AsCustomException();
break;
}
}
}
_logger?.LogTrace($"Built exception {CustomException}");
return CustomException;
}
#region Registration
/// <summary>
/// Register an <see cref="IExceptionBuildHandler"/>. The last handler to be added will take precedence.
/// </summary>
/// <param name="handler"></param>
public static void RegisterBuildHandler(IExceptionBuildHandler handler)
{
lock (_handlers)
{
_logger?.LogTrace($"Registering exception build handler {handler}");
_handlers.Add(handler);
}
}
/// <summary>
/// Register a logger
/// </summary>
/// <param name="logger"></param>
public static void RegisterLogger(ICustomLogger logger)
{
_logger = logger;
_logger?.LogTrace($"Registered logger in the exception builder");
}
#endregion Registration
private static CustomException AsCustomException(this Exception ex)
{
return ex is CustomException CustomException
? CustomException
: new CustomException(ex);
}
}
It all started with the source code for NonCapturingTimer, a static factory class that was creating a System.Threading.Timer without capturing the execution context and was described as "A convenience API for interacting with System.Threading.Timer in a way that doesn't capture the ExecutionContext. We should be using this (or equivalent) everywhere we use timers to avoid rooting any values stored in asynclocals.". What did that even mean?Update:
The problem described here was slightly false. The issue was that IOptionsSnapshot was registered as Scoped and I was just getting the service from the root IServiceProvider. The solution is to call provider.CreateScope() and with that scope as a provider use ActivatorUtilities. Even better, create a scope, then use it to get an instance of a business class that now would support Scoped services as well as Transient, just like a Controller would.
Warning, though: you need to dispose the scope, but you need to make sure you don't use any service that was created there outside the scope (after disposing).
I guess another solution would be to somehow register IOptionsSnapshot<> as transient, but haven't tried it.
And now for the original post
I was trying to create an instance of an object from a service provider to resolve any dependencies, using ActivatorUtilities.CreateInstance<MyObject>(_serviceProvider) and I was getting the exception:
System.InvalidOperationException
HResult=0x80131509
Message=Cannot resolve scoped service 'Microsoft.Extensions.Options.IOptionsSnapshot`1[ExternalConfiguration]' from root provider.
My object was receiving a parameter of type IOptionsSnapshot<ExternalConfiguration> and upon further investigation, my service provider (which came as a resolution from the dependency injection for IServiceProvider) was actually a ServiceProviderEngineScope which just refused to resolve any IOptionsSnapshot! Funny enough, if I replaced IOptionsSnapshot with IOptionsMonitor, which in my mind is a heavier interface, it worked without issues. Further still, the problem appeared only inside an IHostedService (a BackgroundService hooked up with services.AddHostedService<T>); if I wrote the same code in a controller action, for instance, it worked fine.
The .NET 2+ implementation of IOptionsSnapshot<T> is OptionsManager<T>. If I manually resolved an instance of OptionsManager before my object, then added it as a parameter, the code worked:
var optionsSnapshot = ActivatorUtilities.CreateInstance<OptionsManager<TestOptions>>(_serviceProvider);
var myObject = ActivatorUtilities.CreateInstance<MyObject>(_serviceProvider, optionsSnapshot);
So, specifically, the issue is that in .NET Core, the service provider implementation cannot resolve IOptionsSnapshot interfaces in worker services. You can still do that manually, but I suspect it is a bug, since there is no problem using an IOptionsMonitor instead of IOptionsSnapshot.
A possible solution is to use an additional service provider only for IOptionsSnapshot. Warning, this will not work in a general situation if the dependencies from the additional service provider also need parameters that would be found in the original service provider:
// initialization code
var serviceCollection = new ServiceCollection();
serviceCollection.AddSingleton(
typeof(IOptionsSnapshot<>),
typeof(OptionsManager<>)
);
serviceCollection.AddSingleton(
typeof(IOptionsFactory<>),
typeof(OptionsFactory<>)
);
_additionalServiceProvider = serviceCollection.BuildServiceProvider();
// resolution code
var constructor = typeof(MyObject).GetConstructors()
.Where(ci=>ci.IsPublic)
.Single();
var args = constructor.GetParameters()
.Select(p =>
{
try
{
return _serviceProvider.GetService(p.ParameterType);
}
catch
{
return _additionalServiceProvider.GetService(p.ParameterType);
}
})
.ToArray();
return ActivatorUtilities.CreateInstance<MyObject>(_serviceProvider, args);
.NET Core comes with its own dependency injection engine, separated in the Microsoft.Extensions.DependencyInjection package, and ASP.Net Core uses it by default. In a very simplistic description, it uses an IServiceCollection to add services to, then it builds an IServiceProvider from that list, an interface which returns an implementation based on a type or null if finding none. Any change in the list of services is not supported. There are situations, though, where you want to add new services. One of them being dynamically resolving new types.// IAdvancedServiceProvider either injected
// or resolved via serviceProvider.GetService<IAdvancedServiceProvider>
// or even serviceProvider as IAdvancedServiceProvider
advancedServiceProvider.ServiceCollection.AddSingleton...
/// <summary>
/// Service provider that allows for dynamic adding of new services
/// </summary>
public interface IAdvancedServiceProvider : IServiceProvider
{
/// <summary>
/// Add services to this collection
/// </summary>
IServiceCollection ServiceCollection { get; }
}
/// <summary>
/// Service provider that allows for dynamic adding of new services
/// </summary>
public class AdvancedServiceProvider : IAdvancedServiceProvider, IDisposable
{
private readonly List<ServiceProvider> _serviceProviders;
private readonly NotifyChangedServiceCollection _services;
private readonly object _servicesLock = new object();
private List<ServiceDescriptor> _newDescriptors;
private Dictionary<Type, object> _resolvedObjects;
/// <summary>
/// Initializes a new instance of the <see cref="AdvancedServiceProvider"/> class.
/// </summary>
/// <param name="services">The services.</param>
public AdvancedServiceProvider(IServiceCollection services)
{
// registers itself in the list of services
services.AddSingleton<IAdvancedServiceProvider>(this);
_serviceProviders = new List<ServiceProvider>();
_newDescriptors = new List<ServiceDescriptor>();
_resolvedObjects = new Dictionary<Type, object>();
_services = new NotifyChangedServiceCollection(services);
_services.ServiceAdded += ServiceAdded;
_serviceProviders.Add(services.BuildServiceProvider(true));
}
private void ServiceAdded(object sender, ServiceDescriptor item)
{
lock (_servicesLock)
{
_newDescriptors.Add(item);
}
}
/// <summary>
/// Add services to this collection
/// </summary>
public IServiceCollection ServiceCollection { get => _services; }
/// <summary>
/// Gets the service object of the specified type.
/// </summary>
/// <param name="serviceType">An object that specifies the type of service object to get.</param>
/// <returns>A service object of type serviceType. -or- null if there is no service object of type serviceType.</returns>
public object GetService(Type serviceType)
{
lock (_servicesLock)
{
// go through the service provider chain and resolve the service
var service = GetServiceInternal(serviceType);
// if service was not found and we have new registrations
if (service == null && _newDescriptors.Count > 0)
{
// create a new service collection in order to build the next provider in the chain
var newCollection = new ServiceCollection();
foreach (var descriptor in _services)
{
foreach (var descriptorToAdd in GetDerivedServiceDescriptors(descriptor))
{
((IList<ServiceDescriptor>)newCollection).Add(descriptorToAdd);
}
}
var newServiceProvider = newCollection.BuildServiceProvider(true);
_serviceProviders.Add(newServiceProvider);
_newDescriptors = new List<ServiceDescriptor>();
service = newServiceProvider.GetService(serviceType);
}
if (service != null)
{
_resolvedObjects[serviceType] = service;
}
return service;
}
}
private IEnumerable<ServiceDescriptor> GetDerivedServiceDescriptors(ServiceDescriptor descriptor)
{
if (_newDescriptors.Contains(descriptor))
{
// if it's a new registration, just add it
yield return descriptor;
yield break;
}
if (!descriptor.ServiceType.IsGenericTypeDefinition)
{
// for a non open type generic singleton descriptor, register a factory that goes through the service provider
yield return ServiceDescriptor.Describe(
descriptor.ServiceType,
_ => GetServiceInternal(descriptor.ServiceType),
descriptor.Lifetime
);
yield break;
}
// if the registered service type for a singleton is an open generic type
// we register as factories all the already resolved specific types that fit this definition
if (descriptor.Lifetime == ServiceLifetime.Singleton)
{
foreach (var servType in _resolvedObjects.Keys.Where(t => t.IsGenericType && t.GetGenericTypeDefinition() == descriptor.ServiceType))
{
yield return ServiceDescriptor.Describe(
servType,
_ => _resolvedObjects[servType],
ServiceLifetime.Singleton
);
}
}
// then we add the open type registration for any new types
yield return descriptor;
}
private object GetServiceInternal(Type serviceType)
{
foreach (var serviceProvider in _serviceProviders)
{
var service = serviceProvider.GetService(serviceType);
if (service != null)
{
return service;
}
}
return null;
}
/// <summary>
/// Dispose the provider and all resolved services
/// </summary>
public void Dispose()
{
lock (_servicesLock)
{
_services.ServiceAdded -= ServiceAdded;
foreach (var serviceProvider in _serviceProviders)
{
try
{
serviceProvider.Dispose();
}
catch
{
// singleton classes might be disposed twice and throw some exception
}
}
_newDescriptors.Clear();
_resolvedObjects.Clear();
_serviceProviders.Clear();
}
}
/// <summary>
/// An IServiceCollection implementation that exposes a ServiceAdded event for added service descriptors
/// The collection doesn't support removal or inserting of services
/// </summary>
private class NotifyChangedServiceCollection : IServiceCollection
{
private readonly IServiceCollection _services;
/// <summary>
/// Fired when a descriptor is added to the collection
/// </summary>
public event EventHandler<ServiceDescriptor> ServiceAdded;
/// <summary>
/// Initializes a new instance of the <see cref="NotifyChangedServiceCollection"/> class.
/// </summary>
/// <param name="services">The services.</param>
public NotifyChangedServiceCollection(IServiceCollection services)
{
_services = services;
}
/// <summary>
/// Get the value at index
/// Setting is not supported
/// </summary>
public ServiceDescriptor this[int index]
{
get => _services[index];
set => throw new NotSupportedException("Inserting services in collection is not supported");
}
/// <summary>
/// Count of services in the collection
/// </summary>
public int Count { get => _services.Count; }
/// <summary>
/// Obviously not
/// </summary>
public bool IsReadOnly { get => false; }
/// <summary>
/// Adding a service descriptor will fire the ServiceAdded event
/// </summary>
/// <param name="item"></param>
public void Add(ServiceDescriptor item)
{
_services.Add(item);
ServiceAdded.Invoke(this, item);
}
/// <summary>
/// Clear the collection is not supported
/// </summary>
public void Clear() => throw new NotSupportedException("Removing services from collection is not supported");
/// <summary>
/// True is the item exists in the collection
/// </summary>
public bool Contains(ServiceDescriptor item) => _services.Contains(item);
/// <summary>
/// Copy items to array of service descriptors
/// </summary>
public void CopyTo(ServiceDescriptor[] array, int arrayIndex) => _services.CopyTo(array, arrayIndex);
/// <summary>
/// Enumerator for service descriptors
/// </summary>
public IEnumerator<ServiceDescriptor> GetEnumerator() => _services.GetEnumerator();
/// <summary>
/// Index of item in the list
/// </summary>
public int IndexOf(ServiceDescriptor item) => _services.IndexOf(item);
/// <summary>
/// Inserting is not supported
/// </summary>
public void Insert(int index, ServiceDescriptor item) => throw new NotSupportedException("Inserting services in collection is not supported");
/// <summary>
/// Removing items is not supported
/// </summary>
public bool Remove(ServiceDescriptor item) => throw new NotSupportedException("Removing services from collection is not supported");
/// <summary>
/// Removing items is not supported
/// </summary>
public void RemoveAt(int index) => throw new NotSupportedException("Removing services from collection is not supported");
/// <summary>
/// Enumerator for objects
/// </summary>
IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)_services).GetEnumerator();
}
}
Long story short, check out this answer to a StackOverflow question: Package destination of restore of .net-core projects is always global package directory<?xml version="1.0" encoding="utf-8"?>
<configuration>
<config>
<add key="repositoryPath" value="./packages" />
<add key="globalPackagesFolder" value="./packages" />
</config>
<settings>
<repositoryPath>./packages</repositoryPath>
</settings>
...
</configuration>
We already know how to load types in .NET Framework and we know what they say we should use in .NET Core. But what about Standard? Is that a trick question? Sort of. Right now we have two .NET Standard and three .NET Core versions, albeit .NET Core 3 is in preview mode. The signature for AssemblyLoadContext and how it is used has changed dramatically. Core 3 enables context unloading, but Standard 2 does not. So you either are forced to build your library as Core 3 or you have to not use Unloading contexts or use reflection, which is not robust and probably will not be needed with the possible arrival of Standard 3.var context = new AssemblyLoadContext("testContext", true);The output is:
var interfaceAssembly = context.LoadFromAssemblyPath(interfaceAssemblyPath);
var interfaceType = interfaceAssembly.GetType("TestInterfaceLibrary.ITestInterface");
Console.WriteLine(interfaceType?.ToString()??"interface type not loaded");
var implementationAssembly = context.LoadFromAssemblyPath(implementationAssemblyPath);
var implementationType = implementationAssembly.GetType("TestImplementationLibrary.TestImplementation");
Console.WriteLine(implementationType?.ToString() ?? "implementation type not loaded");
Console.WriteLine("implementation implements interface: "+interfaceType.IsAssignableFrom(implementationType));
context.Unload();
TestInterfaceLibrary.ITestInterface
TestImplementationLibrary.TestImplementation
implementation implements interface: True
var context = new AssemblyLoadContext("testContext", true);
context.Resolving += Context_Resolving;
var implementationAssembly = context.LoadFromAssemblyPath(implementationAssemblyPath);
var implementationType = implementationAssembly.GetType("TestImplementationLibrary.TestImplementation", true);
Console.WriteLine(implementationType?.ToString() ?? "implementation type not loaded");
var interfaceAssembly = context.LoadFromAssemblyPath(interfaceAssemblyPath);
var interfaceType = interfaceAssembly.GetType("TestInterfaceLibrary.ITestInterface", true);
Console.WriteLine(interfaceType?.ToString() ?? "interface type not loaded");
Console.WriteLine("implementation implements interface: " + interfaceType.IsAssignableFrom(implementationType));
context.Resolving -= Context_Resolving;
context.Unload();
private static Assembly Context_Resolving(AssemblyLoadContext context, AssemblyName assemblyName)
{
var expectedPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, assemblyName.Name + ".dll");
return context.LoadFromAssemblyPath(expectedPath);
}
var context = new AssemblyLoadContext("testContext", true);the output will show
context.Resolving += Context_Resolving;
var implementationAssembly = context.LoadFromAssemblyPath(implementationAssemblyPath);
var implementationType = implementationAssembly.GetType("TestImplementationLibrary.TestImplementation", true);
Console.WriteLine(implementationType?.ToString() ?? "implementation type not loaded");
context.Resolving -= Context_Resolving;
context.Unload();
context = new AssemblyLoadContext("testContext2", true);
context.Resolving += Context_Resolving;
var interfaceAssembly = context.LoadFromAssemblyPath(interfaceAssemblyPath);
var interfaceType = interfaceAssembly.GetType("TestInterfaceLibrary.ITestInterface", true);
Console.WriteLine(interfaceType?.ToString() ?? "interface type not loaded");
Console.WriteLine("implementation implements interface: " + interfaceType.IsAssignableFrom(implementationType));
context.Resolving -= Context_Resolving;
context.Unload();
implementation implements interface: False
private static int CountTypes(string typeName)
{
return AppDomain.CurrentDomain.GetAssemblies()
.SelectMany(assembly => assembly.GetTypes().Where(t => t.FullName == typeName))
.Count();
}
var context = new AssemblyLoadContext("testContext", true);
context.Resolving += Context_Resolving;
var referencedInterfaceType = typeof(ITestInterface);
Console.WriteLine(referencedInterfaceType?.ToString() ?? "interface type not loaded");
var interfaceAssembly = context.LoadFromAssemblyPath(interfaceAssemblyPath);
var interfaceType = interfaceAssembly.GetType("TestInterfaceLibrary.ITestInterface", true);
Console.WriteLine(interfaceType?.ToString() ?? "interface type not loaded");
Console.WriteLine($"Types are the same: {interfaceType==referencedInterfaceType}");
Console.WriteLine($"Number of types with name {interfaceType.FullName}: {CountTypes(interfaceType.FullName)}");
context.Resolving -= Context_Resolving;
context.Unload();
Console.WriteLine($"Number of types with name {interfaceType.FullName}: {CountTypes(interfaceType.FullName)}");
TestInterfaceLibrary.ITestInterfaceThe types are always 2!
TestInterfaceLibrary.ITestInterface
Types are the same: False
Number of types with name TestInterfaceLibrary.ITestInterface: 2
Number of types with name TestInterfaceLibrary.ITestInterface: 2
public class TypeLoader : IDisposable
{
private readonly AssemblyLoadContext _context;
public TypeLoader()
{
_context = new AssemblyLoadContext(GetType().FullName, true);
_context.Resolving += Context_Resolving;
}
private Assembly Context_Resolving(AssemblyLoadContext context, AssemblyName assemblyName)
{
var expectedPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, assemblyName.Name + ".dll");
return context.LoadFromAssemblyPath(expectedPath);
}
public Type LoadType(string typeName, string assemblyPath)
{
var type = AppDomain.CurrentDomain.GetAssemblies()
.SelectMany(assembly => assembly.GetTypes().Where(t => t.FullName == typeName))
.FirstOrDefault();
if (type != null)
{
return type;
}
var assembly = _context.LoadFromAssemblyPath(assemblyPath);
return assembly.GetType(typeName, true);
}
public void Dispose()
{
_context?.Resolving -= Context_Resolving;
_context?.Unload();
}
}
var interfaceAssemblyPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestInterfaceLibrary.dll");and the result is
var implementationAssemblyPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestImplementationLibrary.dll");
var interfaceTypeName = "TestInterfaceLibrary.ITestInterface";
var implementationTypeName = "TestImplementationLibrary.TestImplementation";
using (var loader = new TypeLoader())
{
Type referencedType = typeof(TestInterfaceLibrary.ITestInterface);
var interfaceType = loader.LoadType(interfaceTypeName, interfaceAssemblyPath);
var implementationType = loader.LoadType(implementationTypeName, implementationAssemblyPath);
Console.WriteLine($@"
referenced type: {referencedType}
interface type: {interfaceType}
implementation type: {implementationType}
referenced and loaded interfaces are the same: {referencedType == interfaceType}
interface implemented: {interfaceType.IsAssignableFrom(implementationType)}");
}
referenced type: TestInterfaceLibrary.ITestInterface
interface type: TestInterfaceLibrary.ITestInterface
implementation type: TestImplementationLibrary.TestImplementation
referenced and loaded interfaces are the same: True
interface implemented: True
public class TypeLoader : IDisposable
{
private readonly DynamicAssemblyLoadContext _context;
public TypeLoader()
{
_context = new DynamicAssemblyLoadContext(GetType().FullName, true);
_context.Resolving += Context_Resolving;
}
private Assembly Context_Resolving(AssemblyLoadContext context, AssemblyName assemblyName)
{
var expectedPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, assemblyName.Name + ".dll");
return context.LoadFromAssemblyPath(expectedPath);
}
public Type LoadType(string typeName, string assemblyPath)
{
var type = AppDomain.CurrentDomain.GetAssemblies()
.SelectMany(ass => ass.GetTypes().Where(t => t.FullName == typeName))
.FirstOrDefault();
if (type != null)
{
return type;
}
var assembly = _context.LoadFromAssemblyPath(assemblyPath);
return assembly.GetType(typeName, true);
}
public void Dispose()
{
_context?.Resolving -= Context_Resolving;
_context?.Unload();
}
private class DynamicAssemblyLoadContext : AssemblyLoadContext
{
public DynamicAssemblyLoadContext(string name, bool isCollectible)
{
}
protected override Assembly Load(AssemblyName assemblyName)
{
return null;
}
public void Unload()
{
}
}
}
public class TypeLoader
{
private readonly object _resolutionLock = new object();
private Assembly Context_Resolving(AssemblyLoadContext context, AssemblyName assemblyName)
{
var expectedPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, assemblyName.Name + ".dll");
return context.LoadFromAssemblyPath(expectedPath);
}
public Type LoadType(string typeName, string assemblyPath)
{
var context = AssemblyLoadContext.Default;
lock (_resolutionLock)
{
context.Resolving += Context_Resolving;
var type = AppDomain.CurrentDomain.GetAssemblies()
.SelectMany(ass => ass.GetTypes().Where(t => t.FullName == typeName))
.FirstOrDefault();
if (type != null)
{
return type;
}
var assembly = context.LoadFromAssemblyPath(assemblyPath);
type = assembly.GetType(typeName, true);
context.Resolving -= Context_Resolving;
return type;
}
}
}
This is more a backup for the extensions that I have installed on the two main IDEs I'm using for my job: Visual Studio and Visual Studio Code.
In order to list the extensions installed, use the command code --list-extensions. For me, this results in this output:
code --install-extension aeschli.vscode-css-formatter
code --install-extension Angular.ng-template
code --install-extension christian-kohler.npm-intellisense
code --install-extension cmstead.jsrefactor
code --install-extension cssho.vscode-svgviewer
code --install-extension danwahlin.angular2-snippets
code --install-extension dbaeumer.jshint
code --install-extension dbaeumer.vscode-eslint
code --install-extension donjayamanne.jquerysnippets
code --install-extension donjayamanne.jupyter
code --install-extension DotJoshJohnson.xml
code --install-extension ecmel.vscode-html-css
code --install-extension eg2.vscode-npm-script
code --install-extension esbenp.prettier-vscode
code --install-extension fabianlauer.vs-code-xml-format
code --install-extension fknop.vscode-npm
code --install-extension HookyQR.beautify
code --install-extension humao.rest-client
code --install-extension joelday.docthis
code --install-extension k--kato.docomment
code --install-extension michelemelluso.code-beautifier
code --install-extension minhthai.vscode-todo-parser
code --install-extension mohsen1.prettify-json
code --install-extension mrmlnc.vscode-scss
code --install-extension ms-mssql.mssql
code --install-extension ms-vscode.csharp
code --install-extension ms-vscode.typescript-javascript-grammar
code --install-extension ms-vscode.vscode-typescript-tslint-plugin
code --install-extension msjsdiag.debugger-for-chrome
code --install-extension naumovs.color-highlight
code --install-extension pmneo.tsimporter
code --install-extension rbbit.typescript-hero
code --install-extension robinbentley.sass-indenrted
code --install-extension wayou.vscode-todo-highlight
In order to install them, use code --install-extension [extension name] for each line.
For Visual Studio, funny enough, in order to export and import your extensions you need to use an extension: Extension Manager 2017, which on my system exports a file in .vsext format:
{
"id": "5f191824-b8a6-47c0-9f96-f607dfd3c09b",
"name": "My Visual Studio extensions",
"description": "A collection of my Visual Studio extensions",
"version": "1.0",
"extensions": [
{
"name": ".NET Portability Analyzer",
"vsixId": "55d15546-28ca-40dc-af23-dfa503e9c5fe"
},
{
"name": "Advanced Installer for Visual Studio 2017",
"vsixId": "Caphyon.AdvancedInstaller.23debb5a-cff4-4b91-88bf-6280f72a7ebb"
},
{
"name": "Azure Data Lake and Stream Analytics Tools",
"vsixId": "1e906ff5-9da8-4091-a299-5c253c55fdc9"
},
{
"name": "Azure Functions and Web Jobs Tools",
"vsixId": "Microsoft.VisualStudio.Web.AzureFunctions"
},
{
"name": "BuildVision",
"vsixId": "837c3c3b-8382-4839-9c9a-807b758a929f"
},
{
"name": "Clean Code .NET",
"vsixId": "CleanCode.NET.9ecfa9bb-0775-48d0-9898-4dbbbd529fe3"
},
{
"name": "Cloud Explorer for VS 2017",
"vsixId": "Microsoft.VisualStudio.CloudExplorer"
},
{
"name": "Code Cracker for C#",
"vsixId": "CodeCracker.Vsix..5b99e64c-1418-4a06-990c-fd4cf01f4f63"
},
{
"name": "Code Graph",
"vsixId": "CodeAtlasVSIX.Company.df5456fb-08ea-4256-b5ff-ecdb3a512ad3"
},
{
"name": "CodeMaid",
"vsixId": "4c82e17d-927e-42d2-8460-b473ac7df316"
},
{
"name": "CommentCop",
"vsixId": "CommentCop..0521EE68-1A5D-4C78-9970-B6A46B03FA6D"
},
{
"name": "EntityFramework Reverse POCO Generator",
"vsixId": "EntityFramework_Reverse_POCO_Generator..d542a934-8bd6-4136-b490-5f0049d62033"
},
{
"name": "Extension Manager 2017",
"vsixId": "e83d71b8-8bfc-4e06-b145-b0388910c016"
},
{
"name": "Fix Mixed Tabs",
"vsixId": "FixMixedTabs.9f1d3050-b986-4b10-ae36-97c6efc5e968"
},
{
"name": "Fix Namespace",
"vsixId": "f073da8c-bb52-41f8-b95a-a6346b1a0b52"
},
{
"name": "MetricsAnalyzer",
"vsixId": "MetricsAnalyzer..8026235d-7afc-401b-8f45-ba8624a07ef5"
},
{
"name": "Microsoft Code Analysis 2017",
"vsixId": "4db2d63d-3320-4fbd-bf80-07f8d1500bd3"
},
{
"name": "Moq.Analyzers",
"vsixId": "Moq.Analyzers..c3c7e3f8-2407-428d-beef-c4557253517b"
},
{
"name": "Object Exporter",
"vsixId": "07fb5b16-f4be-4488-9a19-b4f36d2c05a6"
},
{
"name": "Output enhancer",
"vsixId": "VSOutputEnhancer.Nikolay Balakin.a06be4c3-f97e-425c-8a0d-bdef08ac2abb"
},
{
"name": "Power Commands for Visual Studio",
"vsixId": "PowerCommands.3ecdd89b-f985-483d-8c94-be37de4dc083"
},
{
"name": "Ref12",
"vsixId": "SLaks-Ref12-086C4CE4-7061-4B1F-BC77-B64E4ED71B8E"
},
{
"name": "Reference Conflicts Analyser",
"vsixId": "ff477521-e67b-4ca3-931f-3edf36125d28"
},
{
"name": "Regular Expression Tester Extension",
"vsixId": "a65d58d2-ead8-4eea-a47d-fa60865a6043"
},
{
"name": "ResolveUR - Resolve Unused References",
"vsixId": "637ba02c-3388-4e54-9051-3eea7c51b054"
},
{
"name": "Roslyn Security Guard",
"vsixId": "RoslynSecurityGuard..45fa56c2-16f1-4395-8c10-a5a460084018"
},
{
"name": "Roslynator 2017",
"vsixId": "9289a8ab-1bb6-496b-9992-9f7ea27f66a8"
},
{
"name": "Security Code Scan (for VS2017 and newer)",
"vsixId": "955196A7-ACBF-4F6B-820B-51B8507CE853"
},
{
"name": "Solution Error Visualizer",
"vsixId": "SolutionErrorVisualizer.a392f96b-6b33-4b53-b4bb-3376a05f986c"
},
{
"name": "SonarLint for Visual Studio 2017",
"vsixId": "SonarLint.36871a7b-4853-481f-bb52-1835a874e81b"
},
{
"name": "SQL Search",
"vsixId": "Redgate.SQLSearch.VSExtension.9BD7AEDA-C291-4702-8191-4189B099F3A9"
},
{
"name": "Target Framework Migrator",
"vsixId": "TargetFrameworkMigrator..4f7666b9-e62c-46a1-af25-21ab8742ef00"
},
{
"name": "Trailing Whitespace Visualizer",
"vsixId": "4c1a78e6-e7b8-4aa9-8812-4836e051ff6d"
},
{
"name": "Unit Test Boilerplate Generator",
"vsixId": "UnitTestBoilerplate.RandomEngy.ca0bb824-eb5a-41a8-ab39-3b81f03ba3fe"
},
{
"name": "Visual Studio IntelliCode",
"vsixId": "IntelliCode.VSIX.598224b2-b987-401b-8509-f568d0c0b946"
},
{
"name": "Visual Studio Spell Checker (VS2017 and Later)",
"vsixId": "43EA967E-0DE2-4136-8E52-C6DCFB5C2748"
},
{
"name": "Wix Toolset Visual Studio 2017 Extension",
"vsixId": "WixToolset.VisualStudioExtension.Dev15"
}
]
} Newtonsoft.Json.JsonSerializationException: Unable to serialize instance of 'System.IO.DirectoryInfo'.
at Newtonsoft.Json.Serialization.DefaultContractResolver.ThrowUnableToSerializeError(Object o, StreamingContext context)
at Newtonsoft.Json.Serialization.JsonContract.InvokeOnSerializing(Object o, StreamingContext context)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.OnSerializing(JsonWriter writer, JsonContract contract, Object value)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
// serializing DirectoryInfo without ISerializable will stackoverflow
// https://github.com/JamesNK/Newtonsoft.Json/issues/1541
if (Array.IndexOf(BlacklistedTypeNames, objectType.FullName) != -1)
{
contract.OnSerializingCallbacks.Add(ThrowUnableToSerializeError);
}
var settings = new JsonSerializerSettings
{
ContractResolver = new FileInfoContractResolver()
};
private class FileInfoContractResolver : DefaultContractResolver
{
protected override JsonContract CreateContract(Type objectType)
{
var result = base.CreateContract(objectType);
if (typeof(FileSystemInfo).IsAssignableFrom(objectType))
{
result.OnSerializingCallbacks.Clear();
}
return result;
}
}
private class FileSystemInfoConverter:JsonConverterAnd we use it like this:
{
public override bool CanConvert(Type objectType)
{
return typeof(FileSystemInfo).IsAssignableFrom(objectType);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
return null;
var jObject = JObject.Load(reader);
var fullPath = jObject["FullPath"].Value<string>();
return Activator.CreateInstance(objectType, fullPath);
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var info = value as FileSystemInfo;
var obj = info == null
? null
: new
{
FullPath = info.FullName
};
var token = JToken.FromObject(obj);
token.WriteTo(writer);
}
}
var settings = new JsonSerializerSettings
{
Converters = new List<JsonConverter>
{
new FileSystemInfoConverter()
}
};
var json = JsonConvert.SerializeObject(dir, settings);
var info = JsonConvert.DeserializeObject<DirectoryInfo>(json, settings);
This post starts from a simple question: how do I start a task with timeout? You go to StackOverflow, of course, and find this answer: Asynchronously wait for Task<T> to complete with timeout. It's an elegant solution, mainly to also start a Task.Delay and continue when either task completes. However, in order to cancel the initial operation, one needs to pass the cancellation token to the original task and manually handle it, meaning polluting the entire business code with cancellation logic. This might be OK, yet are there alternatives?/// <summary>This introduces some other issues, like what happens to the monitoring task if you never cancel the token or dispose of the cancellation source, but that's a bit too deep.
/// Executes the long running action and cancels it when needed
/// </summary>
/// <param name="token"></param>
private void LongRunningAction(CancellationToken token)
{
// instantiate a container and keep its reference
var container = new IdentificationContainer();
Task.Run(() =>
{
// wait until the token gets cancelled on another thread
token.WaitHandle.WaitOne();
// this will use the information in the container to kill the action
// (presumably by interrupting external processes or sending some kill signal)
KillLongRunningAction();
});
// this executes the action and populates the identification container if needed
RunLongRunningAction();
}
/// <summary>
/// Run an action and kill it when canceling the token
/// </summary>
/// <param name="action">The action to execute</param>
/// <param name="token">The token</param>
/// <param name="waitForGracefulTermination">If set, the task will be killed with delay so as to allow the action to end gracefully</param>
private static Task RunCancellable(Action action, CancellationToken token, TimeSpan? waitForGracefulTermination=null)
{
// we need a thread, because Tasks cannot be forcefully stopped
var thread = new Thread(new ThreadStart(action));
// we hold the reference to the task so we can check its state
Task task = null;
task = Task.Run(() =>
{
// task monitoring the token
Task.Run(() =>
{
// wait for the token to be canceled
token.WaitHandle.WaitOne();
// if we wanted graceful termination we wait
// in this case, action needs to know about the token as well and handle the cancellation itself
if (waitForGracefulTermination != null)
{
Thread.Sleep(waitForGracefulTermination.Value);
}
// if the task has not ended, we kill the thread
if (!task.IsCompleted)
{
thread.Abort();
}
});
// simply start the thread (and the action)
thread.Start();
// and wait for it to end so we return to the current thread
thread.Join();
// throw exception if the token was canceled
// this will not be reached unless the thread completes or is aborted
token.ThrowIfCancellationRequested();
}, token);
return task;
}
var token = new TaskCanceledException(task).CancellationToken;It might not help too much, especially if you want to use it inside the task itself, but it might help clean up the code.
This should be a simple question with a simple answer, but if you google for Angular Material tooltip styling or length or width you get different answers that are not always complete or even correct. The problem: you have something like <a matTooltip="some message" matTooltipClass="myTooltipClass" ... as per the examples easy to find. However, it doesn't seem to be working. The styling for myTooltipClass does not apply. Here are some points to check off while searching for the problem:<div class="cdk-overlay-container">
<div class="cdk-overlay-connected-position-bounding-box" dir="ltr" style="top: 0px; left: 0px; height: 100%; width: 100%;">
<div id="cdk-overlay-1" class="cdk-overlay-pane mat-tooltip-panel" style="pointer-events: auto; top: 8px; left: 417.625px;">
<mat-tooltip-component aria-hidden="true" class="ng-tns-c34-15 ng-star-inserted" style="zoom: 1;">
<div class="mat-tooltip ng-trigger ng-trigger-state" style="transform-origin: left center; transform: scale(1);">Info about the action</div>
</mat-tooltip-component>
</div>
</div>
</div>
I've stumbled on an article called Create A Dark/Light Mode Switch with CSS Variables which explains how to style your site with CSS variables which you can then change for various "themes". Her solution is to use a little Javascript - and let's be honest, there is nothing wrong with that, everything is using Javascript these days, but what if we mix this idea with "the CSS checkbox hack" as explained in Creating useful interactive elements using only CSS, or "The Checkbox Hack"? Then we could have a controllable theme in our website without any Javascript.:root {
--primary-color: #302AE6;
--secondary-color: #536390;
--font-color: #424242;
--bg-color: #fff;
--heading-color: #292922;
}[data-theme="dark"] {
--primary-color: #9A97F3;
--secondary-color: #818cab;
--font-color: #e1e1ff;
--bg-color: #161625;
--heading-color: #818cab;
}body {
background-color: var(--bg-color);
color: var(--font-color);
/*other styles*/
.....
}Update-Package <name-of-nuget-package> -Reinstall -ProjectName <name-of-project>
^.*?Visit http://docs.nuget.org/docs/workflows/reinstalling-packages for more information. Packages affected: ((?:[^,\s]+(?:, )?)+)\t([^\t]+)\t\t\d+\t\t$and replacement pattern
Update-Package $1 -Reinstall -ProjectName $2
Update-Package Microsoft.Extensions.Configuration -Reinstall -ProjectName MyProject.Common
Update-Package Serilog -Reinstall -ProjectName MyProject.Common
I spent hours trying to manually fix the assembly redirects in a web.config, only to give up and use the default Add-BindingRedirect in the NuGet package manager. And it worked! I have no idea if this won't break something else, but I got it from Rick Strahl's blog and it worked for me. More in his article. Thanks, Rick!