C#3.0(.NET 3.5)引入了对象初始化器语法,这是一种初始化类或集合对象的新方法。对象初始化程序允许您在创建对象时将值分配给字段或属性,而无需调用构造函数。
public class Student
{
public int StudentID { get; set; }
public string StudentName { get; set; }
public int Age { get; set; }
public string Address { get; set; }
}
class Program
{
static void Main(string[] args)
{
Student std = new Student() { StudentID = 1,
StudentName = "Bill",
Age = 20,
Address = "New York"
};
}
}
在上面的示例中,没有任何构造函数的情况下定义了 Student 类。在 Main() 方法中,我们创建了Student对象,并同时为大括号中的所有或某些属性分配了值。这称为对象初始化器语法。
编译器将上述初始化程序编译为如下所示的内容。
Student __student = new Student();
__student.StudentID = 1;
__student.StudentName = "Bill";
__student.Age = 20;
__student.StandardID = 10;
__student.Address = "Test";
Student std = __student;
可以使用集合初始化器语法以与类对象相同的方式初始化集合。
var student1 = new Student() { StudentID = 1, StudentName = "John" };
var student2 = new Student() { StudentID = 2, StudentName = "Steve" };
var student3 = new Student() { StudentID = 3, StudentName = "Bill" } ;
var student4 = new Student() { StudentID = 3, StudentName = "Bill" };
var student5 = new Student() { StudentID = 5, StudentName = "Ron" };
IList<Student> studentList = new List<Student>() {
student1,
student2,
student3,
student4,
student5
};
您还可以同时初始化集合和对象。
IList<Student> studentList = new List<Student>() {
new Student() { StudentID = 1, StudentName = "John"} ,
new Student() { StudentID = 2, StudentName = "Steve"} ,
new Student() { StudentID = 3, StudentName = "Bill"} ,
new Student() { StudentID = 3, StudentName = "Bill"} ,
new Student() { StudentID = 4, StudentName = "Ram" } ,
new Student() { StudentID = 5, StudentName = "Ron" }
};
您还可以将null指定为元素:
IList<Student> studentList = new List<Student>() {
new Student() { StudentID = 1, StudentName = "John"} ,
null
};
初始化程序语法使代码更具可读性,易于将元素添加到集合中。
在多线程中很有用。