C#泛型类型转换列表<T>到列表<BaseType>

Question

我怎么能强制转换List<Car>到 List<MyBaseClass>,在列表中我的代码实例会作为一个对象(程序要求不是故意的),这样做,我会找回vehicleId ..

 public Form1()
    {           
        List<Car> lstCar = new List<Car>();
        lstCar.Add(new Car() { Make = "tootay", Model = "camry", VechicleId = 1 });
        lstCar.Add(new Car() { Make = "honda", Model = "civic", VechicleId = 2 });
        VehicleConverter(lstCar);
    }
    public void VehicleConverter(object obj)
    {
      //Want to typecast it to List<MyBaseClass>            
    }        
}

public class MyBaseClass
{        
    public int VechicleId { get; set; }        
}

public class Car:MyBaseClass
{
    public string Make { get; set; }
}

public class Bike : MyBaseClass
{
    public int CC { get; set; }
}

Answer 1

这是不可能的.

如果有可能,您将能够编写以下内容:

List<Car> carList = new List<Car>();
List<BaseClass> baseList = (List<BaseClass>)carList;
baseList.Add(new Bike());    //I just put a Bike into a List<Car>!

备择方案:

• 将列表声明为 List<BaseCLass>
• 转换为非泛型IList(不推荐)
• 投射到IEnumerable<BaseClass>,使用.NET 4中的协方差

• 传递列表的类型副本:

  VehicleConverter(lstCar.ConvertAll(c => (BaseClass)c));