在运行时确定对象类型 - C＃

Question

我有两个名为CalIntEvent和CalExtEvent的子类，它们有两个名为custId和roomNumber的属性。这些类继承自CalEvent。

我有以下代码但无法访问派生类属性。我如何访问这些？

CalEvent newEvent;   
while (userAns != '1' && userAns != '2')
{
    Console.WriteLine("\nPlease enter 1 for Internal Event or 2 for External Event: ");
    userAns = Console.ReadKey().KeyChar;

}

if (userAns == '1')
{
    newEvent = new CalIntEvent();

}
else
{
    newEvent = new CalExtEvent();
    newEvent.custId = 2;// issue is here<<<<<<
}
newEvent.location = GetUserInput(Field.Location, "Please enter a location");
newEvent.title = GetUserInput(Field.Title, "Please enter a title");
newEvent.description = GetUserInput(Field.Description, "Please enter a description");   

Answer 1

由于custId上定义了CalExtEvent，因此您无法从CalEvent类型的变量中访问它。

您可以做的是在构建CalExtEvent时初始化该属性。这是一个例子：

newEvent = new CalExtEvent() { custId = 2};