addsingleton

Logging to the database with ASP.NET Core

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I was reading about logging in ASP.NET when I came across this statement about logging to the database: When logging to SQL Server, don’t do so directly. Instead, add log messages to an in-memory queue and have a background worker dequeue and insert data to SQL Server. Paraphrased from Microsoft – No asynchronous logger methods … Read more

C# – How to supply IOptions

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The options pattern is an indirect way to dependency inject settings into a registered service. If you’re using code that implements the options pattern, then you’re required to supply an IOptions<T> object. For example, let’s say you’re using the MovieService class and it has the following constructor: This requires you to supply the IOptions<MovieSettings> parameter. … Read more

Calling BuildServiceProvider from application code results in an additional copy of singleton services being created

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When you try to call BuildServiceProvider(), you get the following warning: Warning ASP0000 Calling ‘BuildServiceProvider’ from application code results in an additional copy of singleton services being created. Consider alternatives such as dependency injecting services as parameters to ‘Configure’. There are two scenarios where you may be calling BuildServiceProvider() because you want to resolve services … Read more

C# – Dependency inject BackgroundService into controllers

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Let’s say you have a hosted BackgroundService called DatabaseLoggerService. It runs in the background and logs messages to the database. It has the following definition: You want your controllers to use this for logging. In other words, you want them to depend on ILoggerService, not the concrete DatabaseLoggerService class. First, constructor inject ILoggerService into your … Read more

InvalidOperationException: Unable to resolve service for type

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When the built-in dependency injection functionality is trying to create a type, it tries to resolve all of the constructor parameters. If it can’t resolve one of the parameters, it’ll throw a variation of one of these exceptions: The error you get will depend on how you’re doing registration. First, I’ll show the solution. Then … Read more

C# – How to read configuration from appsettings.json

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The appsettings.json file is a convenient way to store and retrieve your application’s configuration. You can add it to any project and then use the Microsoft.Extensions.Configuration library to work with it. Since appsettings.json is just a JSON file, you can add any section / values you want (this is easier than working with XML-based app.config … Read more