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Articles about working with the appsettings.json configuration file in C#.
When you use ConfigurationSection.Get() to load an object from appsettings.json, it returns null if the section doesn’t exist. Since you’re probably not expecting this to be null, this can lead to problems surfacing in unexpected places, such as getting a NullReferenceException: Note: If you’re using ASP.NET Core, you’ll be referring to the config via builder.Configuration … Read more
If you’re trying to use ConfigurationBuilder to read appsettings.json, you probably have the following code snippet and are running into compiler errors: This has three different errors, but the compiler only shows you one error at a time. This is due to the way this is designed – ConfigurationBuilder is in one library and its … Read more
User Secrets are stored in secrets.json. This file is specific to your application. Once you know the path of secrets.json, you can load and update it. Here’s an example of how to update secrets.json programmatically: Note: 1) For brevity, this isn’t showing all using statements. 2) This is using Newtonsoft because it’s better than System.Text.Json … Read more
You have to overwrite the appsettings.json file to be able to update values programmatically. You have to deal with the whole file, not individual parts of it. The process can be summarized in the following steps: There are two options for deserialization. You can either 1) Deserialize appsettings.json into a dynamic object or 2) Load … Read more
Problem You’ve configured user secrets properly, but the framework will not swap in the secret value at runtime. It appears to not be loading secrets.json at all. Check if you’re using GenerateAssemblyInfo=false in your .csproj file. When you add a user secrets file, it generates a user secrets guid and puts it in your .csproj … Read more
When you launch an ASP.NET Core web app, you may see the following startup logging messages: These messages come from having a console logger. If you’re using Host.CreateDefaultBuilder(), it adds a console logger provider by default. There are two simple ways to get rid of these logging messages: turn off logging in appsettings.json or remove … Read more
The User Secrets feature in .NET Core is a safe, simple way to override values in appsettings.json. The overridden values only exist in a file sitting in your own dev environment, so you don’t accidently commit them to your source control repository. This feature is enabled in ASP.NET by default, and the framework does most … Read more
To add User Secrets in an ASP.NET project in Visual Studio do the following steps: For example, let’s say your appsettings.json looks like this: You want to override ApiKey. In secrets.json you would put this: Now when you run your web API, when you go to use the “ApiKey” from the configuration, it’ll use the … Read more
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 anything to it (as long as it’s valid JSON). Compared with working with the … Read more
