.Net Core中利用反射实现批量依赖注入

在.net core中使用依赖注入是很常见的，最常见的我们会使用以下三种：

services.AddScoped<TestIBLL, TestBLL>();
services.AddSingleton<TestIBLL, TestBLL>();
services.AddTransient<TestIBLL, TestBLL>();

当我们的业务层内容不多的时候这样写没有什么问题，但是加入有100个BLL呢，那样一个一个加会很麻烦，每加一个就要多写一次，而且容易忘记漏掉。.

那么我们的需求是让希望能够实现批量注入，并且可以按照不同的生命周期去实现自动注入，以避免每加一个业务类，就要写一次services.AddScoped<>();

我将通过反射来实现它。

周期 AddScoped  AddSingleton  AddTransient

/// <summary>
/// Add Scoped
/// </summary>
/// <param name="services"></param>
/// <param name="interfaceAssembly"></param>
/// <param name="implementAssembly"></param>
public static void AddScoped(this IServiceCollection services, Assembly interfaceAssembly, Assembly implementAssembly)
{
    var interfaces = interfaceAssembly.GetTypes().Where(t => t.IsInterface);
    var implements = implementAssembly.GetTypes();
    foreach (var item in interfaces)
    {
        var type = implements.FirstOrDefault(x => item.IsAssignableFrom(x));
        if (type != null)
        {
            services.AddScoped(item, type);
        }
    }
}

/// <summary>
/// Add AddSingleton
/// </summary>
/// <param name="services"></param>
/// <param name="interfaceAssembly"></param>
/// <param name="implementAssembly"></param>
public static void AddSingleton(this IServiceCollection services, Assembly interfaceAssembly, Assembly implementAssembly)
{
    var interfaces = interfaceAssembly.GetTypes().Where(t => t.IsInterface);
    var implements = implementAssembly.GetTypes();
    foreach (var item in interfaces)
    {
        var type = implements.FirstOrDefault(x => item.IsAssignableFrom(x));
        if (type != null)
        {
            services.AddSingleton(item, type);
        }
    }
}

/// <summary>
/// Add AddTransient
/// </summary>
/// <param name="services"></param>
/// <param name="interfaceAssembly"></param>
/// <param name="implementAssembly"></param>
public static void AddTransient(this IServiceCollection services, Assembly interfaceAssembly, Assembly implementAssembly)
{
    var interfaces = interfaceAssembly.GetTypes().Where(t => t.IsInterface);
    var implements = implementAssembly.GetTypes();
    foreach (var item in interfaces)
    {
        var type = implements.FirstOrDefault(x => item.IsAssignableFrom(x));
        if (type != null)
        {
            services.AddTransient(item, type);
        }
    }
}

调用：

services.AddTransient(Assembly.Load("xxx.IBll"), Assembly.Load("xxx.Bll"));