我在ASP.NET MVC Beta 6中使用依赖注入时遇到问题。在Startup.ConfigureServices方法中,我注册了DatabaseConfiguration和MyDbContext类。项目启动时,我收到以下错误:
Unable to resolve service for type 'DatabaseConfiguration' while attempting to activate 'MyDbContext'.
我不确定为什么这样做无法解析DatabaseConfiguration类型。据我所知,它已正确注册。
我错过了什么?
// ASP.NET 5 Beta 6 Project
public void ConfigureServices(IServiceCollection services) {
services.Configure<DatabaseConfiguration>(appSettings => ConfigurationBinder.Bind(appSettings, this.Configuration.GetConfigurationSection(nameof(DatabaseConfiguration))));
services.AddTransient<MyDbContext>();
services.AddMvc();
}
public class ValuesController : Controller {
public ValuesController(MintoDbContext tenantRepo) { // ... }
// ...
}
// The following classes are in a Class Libary.
public class MyDbContext : DbContext {
public MyDbContext(DatabaseConfiguration databaseConfiguration) { // ... }
}
public class DatabaseConfiguration {
public string ConnectionString { get; set; }
}
答案 0 :(得分:10)
你的config.json应该是这样的:
{
"DatabaseConfiguration": {
"ConnectionString": "yourconnectionstringhere"
}
}
然后你的DI代码应该是这样的:
services.Configure<DatabaseConfiguration>(configuration.GetConfigurationSection("DatabaseConfiguration"));
然后你真正得到的是
IOptions<DatabaseConfiguration>
因此您需要更改DBContext的构造函数以接收
然后在你的DBContext中,你得到如下的连接字符串:
string connectionString = databaseConfiguration.Options.ConnectionString;
或者您可以获得像
这样的DatabaseConfiguration实例DatabaseConfiguration dbConfig = databaseConfiguration.Options;