自定义容器，利用依赖注入创建对象

///容器：自动生成对象
/// 自动初始化需要的元素（依赖注入DI）

public interface IElevenContainer
{
void RegisterType<IT, T>();
IT Resolve<IT>();
}

//创建对象是使用无参构造器

public class ElevenContainer : IElevenContainer
{
private Dictionary<string, Type> typeContainer = new Dictionary<string, Type>();
public void RegisterType<IT, T>()
{
if (!typeContainer.ContainsKey(typeof(IT).FullName))
typeContainer.Add(typeof(IT).FullName, typeof(T));
}

public IT Resolve<IT>()
{
string key = typeof(IT).FullName;
if (!typeContainer.ContainsKey(typeof(IT).FullName))
{
throw new Exception("没有为{key}的初始化");
}
Type type = typeContainer[key];
//CreateInstance默认调用无参构造器,想要创建的对象的构造器如果是无参的，可以调用该方法
return (IT)Activator.CreateInstance(type);

}

}

//创建对象使用有属性标记的构造器，构造器依赖抽象类，抽象类构造器是无参构造器

public class ElevenContainer : IElevenContainer
{
private Dictionary<string, Type> typeContainer = new Dictionary<string, Type>();
public void RegisterType<IT, T>()
{
if (!typeContainer.ContainsKey(typeof(IT).FullName))
typeContainer.Add(typeof(IT).FullName, typeof(T));
}

public IT Resolve<IT>()
{
string key = typeof(IT).FullName;
if (!typeContainer.ContainsKey(typeof(IT).FullName))
{
throw new Exception("没有为{key}的初始化");
}
Type type = typeContainer[key];
var ctorArray = type.GetConstructors();
ConstructorInfo ctor = null;
if (ctorArray.Count(c => c.IsDefined(typeof(InjectionConstractorAttribute), true)) > 0)
{
//获取有标记属性InjectionConstractorAttribute的构造函数
ctor = ctorArray.FirstOrDefault(c => c.IsDefined(typeof(InjectionConstractorAttribute), true));
}
else
{
//获取构造器参数最多的构造函数
ctor = ctorArray.OrderByDescending(c => c.GetParameters().Length).FirstOrDefault();
}

var paraList = ctor.GetParameters();
Object[] paramArray = new object[paraList.Length];
int i = 0;
foreach (var param in paraList)
{
//方法一：构造函数依赖的参数对象的构造函数是无参的
//获取参数接口类型(代码是上层依赖下层的抽象)
Type interfaceType = param.ParameterType;
if (typeContainer.ContainsKey(interfaceType.FullName))
{
//获取参数
Type paramType = this.typeContainer[interfaceType.FullName];
//创建参数对象
Object objectParam = Activator.CreateInstance(paramType);
paramArray[i] = objectParam;
i++;
}
}
return (IT)Activator.CreateInstance(type, paramArray);

}

//创建对象使用有属性标记的构造器，构造器依赖抽象类，抽象类构造器是构造器依赖另外的抽象类，使用递归

public class ElevenContainer : IElevenContainer
{
private Dictionary<string, Type> typeContainer = new Dictionary<string, Type>();
public void RegisterType<IT, T>()
{
if (!typeContainer.ContainsKey(typeof(IT).FullName))
typeContainer.Add(typeof(IT).FullName, typeof(T));
}

public IT Resolve<IT>()
{
string key = typeof(IT).FullName;
if (!typeContainer.ContainsKey(typeof(IT).FullName))
{
throw new Exception("没有为{key}的初始化");
}
Type type = typeContainer[key];
return (IT)Resolve(type);

}

public object Resolve(Type type)
{
var ctorArray = type.GetConstructors();
ConstructorInfo ctor = null;
if (ctorArray.Count(c => c.IsDefined(typeof(InjectionConstractorAttribute), true)) > 0)
{
//获取有标记属性InjectionConstractorAttribute的构造函数
ctor = ctorArray.FirstOrDefault(c => c.IsDefined(typeof(InjectionConstractorAttribute), true));
}
else
{
//获取构造器参数最多的构造函数
ctor = ctorArray.OrderByDescending(c => c.GetParameters().Length).FirstOrDefault();
}

var paraList = ctor.GetParameters();
Object[] paramArray = new object[paraList.Length];
int i = 0;
foreach (var param in paraList)
{
Type interfaceType = param.ParameterType;
if (typeContainer.ContainsKey(interfaceType.FullName))
{
Type paramType = this.typeContainer[interfaceType.FullName];
var ParaObject = Resolve(paramType);
paramArray[i] = ParaObject;
i++;
}
}
return Activator.CreateInstance(type, paramArray);

}

public class Power: IPower
{
[InjectionConstractorAttribute]
public Power(IMicroPhone phone)
{
Console.WriteLine($"{phone.GetType().FullName}");
}
public Power()
{
Console.WriteLine($"{this.GetType().FullName}");
}
public Power(IMicroPhone phone, IPhone applePhone)
{
Console.WriteLine($"{phone.GetType().FullName} {applePhone.GetType().FullName}");
}

}

main函数：

IElevenContainer container = new ElevenContainer();
container.RegisterType<IMicroPhone, MicroPhone>();
container.RegisterType<IPower, Power>();
IPower power = container.Resolve<IPower>();

Console.ReadLine();

原文地址：https://www.cnblogs.com/fblogs/p/12169123.html