配置项相关

读取Appsetting.json的内容

有配置项 BookStoreDatabase 如下：

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "BookStoreDatabase": {
    "ConnectionString": "mongodb://localhost:27017",
    "DatabaseName": "BookStore",
    "BooksCollectionName": "Books"
  }
}

如果想使用实体类模型一次性读取，首先新建相应视图模型

public class BookStoreDatabaseSettings
{
    public string ConnectionString { get; set; } = null!;
    public string DatabaseName { get; set; } = null!;
    public string BooksCollectionName { get; set; } = null!;
}

然后在Program.cs中，使用.NET类库的方法，把配置实例在依赖关系注入 (DI) 容器中注册

var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.Configure<BookStoreDatabaseSettings>(builder.Configuration.GetSection("BookStoreDatabase"));