Use environment-based settings to manage configuration values in your .NET Core application. This means that instead of hardcoding configuration values in your code, you should store them in environment variables or configuration files that can be easily changed based on the environment your application is running in. This approach has several benefits:

• Improved security: By storing sensitive configuration values like API keys or database connection strings in environment variables, you can prevent them from being accidentally committed to source control or exposed in logs.
• Greater flexibility: By separating configuration values from your code, you can easily change them based on the environment your application is running in. For example, you might have different database connection strings for your development, staging, and production environments.
• Easier deployment: By using environment-based settings, you can deploy the same code to multiple environments without having to modify it for each environment.

To use environment-based settings in your .NET Core application, you can use the built-in configuration system. This system allows you to read configuration values from a variety of sources, including environment variables, JSON files, and command-line arguments. Here's an example of how you might use the configuration system to read a database connection string from an environment variable:

public void ConfigureServices(IServiceCollection services)
{
    string connectionString = Environment.GetEnvironmentVariable("DATABASE_CONNECTION_STRING");
    services.AddDbContext<MyDbContext>(options => options.UseSqlServer(connectionString));
}

In this example, we're using the GetEnvironmentVariable method to read the value of the DATABASE_CONNECTION_STRING environment variable. We then pass this value to the UseSqlServer method to configure our database context. By using environment-based settings in this way, we can easily change the database connection string based on the environment our application is running in.