c# - 工厂创建相同界面的不同对象

Question

我有 1 个接口(interface):

public interface ISummary
{
   int EventId {get; set;}
}

还有许多实现这个接口(interface)的具体类:

public class EmployeeSummary : ISummary
{
   public int EventId {get; set;},
   public int TotalUniqueCount {get; set;}
   public int Location {get; set;}
}

public class CarSummary : ISummary
{
   public int EventId {get; set;}
   public int TotalMiles {get; set;}
   public int TotalHours {get; set;}
}

等....

唯一的共享属性是 EventId。有没有办法让 1 个工厂方法创建所有这些摘要对象？我想要 1 个入口点来决定要创建哪些对象。

所以像这样:

public ISummary CreateSummary(ConcreteObjectType with properties)
{
if EmployeeSummary
 --Call this method to create and return EmployeeSummary

if CarSummary
 --Call this method create and return CarSummary
}

我希望其他类中的所有调用都调用此方法，而不是自己创建对象。

我遇到的问题是如何将分配给对象的属性传递给此 CreateSummary 方法，因为对象的所有属性都将不同？

如果有更好的设计模式我应该在这里使用，我愿意改变此时的对象。

Answer 1

嗯，这就是为什么 Factory Method模式存在:

public class SummaryFactory
{        
    // new instance with values assigned by action delegate or default
    public T Create<T>(Action<T> action = null) where T : ISummary, new()
    {
        var result = new T();
        action?.Invoke(result);             
        return result;
    }

    // with object to assign value from (map) 
    public T Create<T>(object map) where T : ISummary, new()
    {
        var result = new T();
        PropertyInfo[] props = map.GetType().GetProperties();
        PropertyInfo[] tProps = typeof(T).GetProperties();

        foreach (var prop in props)
        {
            var upperPropName = prop.Name.ToUpper();
            var foundProperty = tProps.FirstOrDefault(p => p.Name.ToUpper() == upperPropName);
            foundProperty?.SetValue(result, prop.GetValue(map));
        }
        return result;
    }

    // new instance without generic parameters
    public object Create(Type type)
    {
        var instance = Activator.CreateInstance(type);

        // add some other logic that changes instance
        return instance;
    }
}

现在你可以使用这个工厂了:

var factory = new SummaryFactory();
var carSummary = factory.Create<CarSummary>();
var carSummary2 = factory.Create<CarSummary>(car => { car.TotalMiles = 50; });
var carSummary3 = factory.Create<CarSummary>(new { TotalMiles = 50 });
var employeeSummary = factory.Create(typeof(EmployeeSummary));