Question

我有一个名为employee的类，它有一个名为insurance的字段，类似于此类

public class Employee
{
    public string Name;
    public Insurance Insurance;
}

我有另一个叫保险的课程

public class Insurance
{
    public int PolicyId;
    public String PolicyName;
}

现在在主程序中我想做类似

的事情

var myEmployee = new Employee();
myEmployee.Name = "Jhon";
myEmployee.Insurance.PolicyId = 123 ;
myEmployee.Insurance.PolicyName = "Life Time" ;

C＃抱怨，我知道如何通过创建Insurance类的实例来修复它。

我的问题是我可以以某种方式使用类似

在主程序中以我想要的方式分配字段的值

**

myEmployee.Insurance.PolicyId = 123 ;
myEmployee.Insurance.PolicyName = "Life Time" ;

** 我试过了

 public class Employee
    {

        public Employee()
        {
            Insurance Insurance = new Insurance();
        }

        public String Name;
        public Insurance Insurance;



        public class Insurance
        {
            public int PolicyId;
            public String PolicyName;
        } 
    }

在我尝试的主要方法

class Program
    {
        static void Main(string[] args)
        {
            var joe = new Employee();
            joe.Name = "Joe";
            joe.Insurance.

        }

我收到此错误 -

错误2“ConsoleApplication1.Employee.Insurance”与“ConsoleApplication1.Employee.Insurance”之间的歧义c：\ users \ lenovo \ documents \ visual studio 2012 \ Projects \ ConsoleApplication1 \ ConsoleApplication1 \ Program.cs 15 17 ConsoleApplication1

Answer 1

您可以在Employee的构造函数中实例化保险，因此它会自动为您完成。您可以提供默认值，以确保在以后访问时尚未将其定义为有效。

public class Employee
{
    Insurance Insurance { get; set; }

    public Employee()
    {
        this.Insurance = new Insurance() { PolicyId = -1 };
    }
}

public class Insurance
{
    public int PolicyId { get; set; }
    public string PolicyName { get; set; }
}

或者保持嵌套的类：

public class Employee
{
    Insurance InsurancePolicy { get; set; }

    public Employee()
    {
        this.InsurancePolicy = new Insurance() { PolicyId = -1 };
    }
    public class Insurance
    {
        public int PolicyId { get; set; }
        public string PolicyName { get; set; }
    }
}

Answer 2

无需更改Employee类，您可以使用对象初始值设定项：

var myEmployee = new Employee 
{
    Name = "Jhon",
    Insurance = new Insurance
    {
        PolicyId = 123,
        PolicyName = "Life Time"
    }
};

或者，也许最好，您可以让Employee类在其构造函数中创建Insurance的新实例（如在其他答案中），或者另一个选项是执行此操作在Insurance属性getter本身，所以只有在你使用它时它才被实例化。以下是后者的一个例子：

class Employee 
{
    private Insurance insurance;

    public Insurance Insurance
    {
        get
        {
            if (insurance == null)
            {
                insurance = new Insurance();
            }
            return insurance;
        }
    }
}

最后，我建议您不要构建具有所有公共字段的类，除非您确实知道这是您想要的。相反，我会考虑在字段上使用属性。我已将其他建议纳入以下代码，并提供了我自己的建议：

public class Employee
{
    public Employee() 
    {
        this.Insurance = new Insurance();
    }

    // Perhaps another constructor for the name?
    public Employee(string name)
        : this()
    {
        this.Name = name;
    }

    public string Name { get; set; }
    public Insurance Insurance { get; private set; }
}

public class Insurance
{
    public int PolicyId { get; set; }
    public string PolicyName { get; set; }
}

Answer 3

当然，但是如何分配属于null对象的内容？您需要在Insurance的构造函数中实例化Employee。

public Employee()
{
     this.Insurance = new Insurance();
}

编辑关于你的评论：按照这种方法，您将能够使用两个点访问myEmplyee.Insurance.PolicyID。构造函数是里面的 Employee的类，所以一旦实现它，你就不必输入比你已经尝试过的更多的东西了。

Answer 4

您可以为您的员工编写一个构建器，以便实例化Insurance

public class Employee
{
    public Employee()
    {
        this.Insurance = new Insurance();
    }
    public string Name;
    public Insurance Insurance;
}

初始化嵌套对象属性

4 个答案: