ASP.NET Core-DI-使用操作 <T> 或IOption <T>

Question

I'm trying to understand the different between using IOptions<T> and Action<T> and when to use what.

I have a library that is using an extension method for IServiceCollection where I need to configure my service as well as configure a EF DbContext .

Example:

namespace Microsoft.Extensions.DependencyInjection 
{
    public static void AddModule(this IServiceCollection services, IOptions<SomeOptionsClass> options) {
        services.AddDbContext<MyContext>(contextOptions => contextOptions.UseSqlServer(SomeOptionsClass.ConnectionString));
    }
}

How do I get the ConnectionString property value from the SomeOptionsClass ?

Answer 1

Not sure why the need for IOptions<T> here.

Should be able to get the connection string from Configuration ( appsetting ) during startup. IOptions<T> is usually used for injecting setting into classes

I suggest simplifying the API to expect the connection string

namespace Microsoft.Extensions.DependencyInjection  {
    public static void AddModule(this IServiceCollection services, string connectionString) {
        services.AddDbContext<MyContext>(contextOptions => contextOptions.UseSqlServer(connectionString));
    }
}

This would allow users more flexibility when configuring the module.

For example in the configure services in composition root you can access configuration and extract the connection string to be used as needed

//...

services.AddModule(Configuration["Appsettings Key Here"]);