如何使用Ninject绑定与所需的连接字符串类的构造函数？ [英] How to bind classes with required connection string in constructor using Ninject?

问题描述

如何使用Ninject绑定所需的连接字符串类的构造函数？

How to bind classes with required connection string in constructor using Ninject?

下面是我使用的类：

AppService服务类：

using SomeProject.LayerB;

namespace SomeProject.LayerA;
{
    public class AppService
    {
        private readonly ISomeRepository someRepository;

        public LocationManagementService(ISomeRepository someRepository)
        {
            this.someRepository = someRepository;
        }

        // other codes ...
    }  
}

SomeRepository 类：

namespace SomeProject.LayerB;
{
    public class SomeRepository : ISomeRepository
    {
        private readonly SomeDbContext context;

        public SomeRepository(SomeDbContext context)
        {
            this.context = context;
        }

        // other codes ...
    }
}

SomeDbContext 类：

namespace SomeProject.LayerB;
{
    public class SomeDbContext : DbContext
    {
        public SomeDbContext(string nameOrConnectionString)
            : base(nameOrConnectionString)
        {
        }

        // other codes ...
    }  
}

然后，我用的 Ninject模块包含以下代码：

Then, I use a Ninject module containing the following code:

namespace SomeProject.LayerC;  
{
    public class SomeModule : NinjectModule
    {
        public override void Load()
        {
            Bind<ISomeRepository>().To<SomeRepository>();

            // My problem is on this part.. I want to provide the connection string on the
            // main program, not here on this class.
            // Bind<SomeDbContext>().ToSelf().WithConstructorArgument("nameOrConnectionString", "the connection string I want to inject");
        }
    } 
} 

主要节目

using SomeProject.LayerA;
using SomeProject.LayerC;

namespace SomeProject.LayerD;
{
    public class MainProgram
    {
        public MainProgram()
        {
            IKernel kernel = new StandardKernel(new SomeModule());

            AppService appService = kernel.Get<AppService>();
        }
    }  
}

注意：该主程序可以参考的唯一层是层1.在这里AppService服务类定位和以及LayerC其中ninject模块中找到。

NOTE: The only layer that main program can reference is LayerA where AppService class is located and as well as LayerC where the ninject module is found.

推荐答案

添加配置类是这样的：

public class Config
{
    public static string ConnectionString { get; set; }
}

和你ninject模块写的：

and in your ninject module write this:

Bind<SomeDbContext>().ToSelf()
   .WithConstructorArgument("nameOrConnectionString", 
       c => Config.ConnectionString);  

然后在你的主要方法，你可以写如下：

then in your main method you could write following:

public class MainProgram
{
    public MainProgram()
    {
        IKernel kernel = new StandardKernel(new SomeModule());
        Config.ConnectionString = "The connection string";
        AppService appService = kernel.Get<AppService>();
    }
}  

更新：

您可以使用 ninject 找到配置类，如果你还不想用静态方法：

You can use ninject to locate config class also if you don't want use static methods:

class Config2
{
    public string ConnectionString { get; set; }
}

在模块：

Bind<Config2>().ToSelf().InSingletonScope();
Bind<SomeDbContext>().ToSelf()
   .WithConstructorArgument("nameOrConnectionString",
       c=>c.Kernel.Get<Config2>().ConnectionString);

在主：

IKernel kernel = new StandardKernel(new SomeModule());
var conf = kernel.Get<Config2>();
conf.ConnectionString = "The connection string";
AppService appService = kernel.Get<AppService>();

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