# .NET Configuration
The configuration system depends on configuration providers - the sources of configuration data.
# Options
services.Configure<MyOptions>(Configuration.GetSection("MyOptions"));
The IOptions<T> instance is registered as a singleton.
Reloading
To support configuration providers that can be reloaded during runtime, we can
inject IOptionsSnapshot<T> instead of IOptions<T>.
The class for out options needs to have properties that:
- are public
- have getters
- have setters (or non-null value if complex type)
- are not indexers
IEnumerable
An IEnumerable<T> property that is initialized cannot be bound to. That's
becasue IEnumerable<T> does not have the Add method.
# Lambda
We are able to customize Options in runtime:
services.Configure<MyOptions>(Configuration.GetSection("MyOptions"));
services.Configure<MyOptions>(options =>
{
options.Mode = Modes.Mode1;
});
The configuration system executes both operations. First, the IConfiguration
is read and then Mode property is overwritten.
# Without Options
# Nuget packages:
- Microsoft.Extensions.Configuration;
- Microsoft.Extensions.Configuration.Files.Json
- Microsoft.Extensions.Configuration.Binder
# Building
private static AppConfiguration GetConfiguration()
{
var rawConfig = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json")
.Build();
return ConfigurationBinder.Get<AppConfiguration>(rawConfig);
}