How to understand object initializer and collection initializer in C # 3.0

This article mainly explains "how to understand object initializers and set initializers in C # 3.0". The explanation in this article is simple and clear and easy to learn and understand. let's study and learn how to understand object initializers and set initializers in C# 3.0.

Some questions about object initializers (Object Initializers):

Question 1: does the object initializer allow only partial values to be assigned? That is, some of these values are not assigned.

Answer: allow; refer to the following code.

Question 2: does the object initializer allow you to assign values to members of internal? (private members certainly don't have to think about it, and they certainly can't assign values. )

Answer: allow; refer to the code below.

Public class Person {public string FirstName {get; set;} public string LastName {get; set;} public int Age {get; set;} private int test01 = 25; internal int test02;} class Program {static void Main (string [] args) {Person person = new Person {FirstName = "Scott", LastName = "Guthrie", test02 = 56,}; Console.WriteLine (person.test02); Console.WriteLine (person.Age); Console.ReadLine ();}}

Question 3: can object initializers be used in conjunction with constructors?

Answer: you can see the following code for normal use:

Var cookie3 = new System.Net.Cookie ("MyCookie", "Jose") {Comment = "a cookie"}

We assign a value to the name and value of Cookie in the constructor and a value to the Comment property in the initialization constructor.

Question 4: which constructor assignment and initialization constructor assignment is performed?

For example, the following code, which one is the result?

Static void Main (string [] args) {var cookie = new System.Net.Cookie ("MyCookie", "Jose") {Name = "test02", Comment = "a cookie"}; Console.WriteLine (cookie.Name); Console.ReadLine ();}

Answer:

The constructor is executed earlier than the initialization constructor.

The message written by the above WriteLine is: test02

Some problems with set initializers (Collection Initializers):

Question 1: can an item in the collection initialization constructor be null?

Answer: yes, see the following code.

Question 2: can the collection initialization constructor initialize Hashtable?

Answer: yes. This is equivalent to initializing the constructor with two objects, see the following code:

Public class Person {public string FirstName {get; set;} public string LastName {get; set;} public int Age {get; set;} private int test01 = 25; internal int test02 } class Program {static void Main (string [] args) {List people = new List {new Person {FirstName = "Scott", LastName = "Guthrie", Age = 32}, new Person {FirstName = "Bill", LastName = "Gates", test02 = 85}, new Person {FirstName = "Susanne", Age = 32}, null,} Hashtable pp = new Hashtable {{1, new Person {FirstName = "Scott", LastName = "Guthrie", Age = 32}}, {2, new Person {FirstName = "Bill", LastName = "Gates", test02 = 85}}, {3, new Person {FirstName = "Susanne", Age = 32}}, {4, null},}; Console.ReadLine () }} Thank you for your reading, the above is the content of "how to understand object initializers and set initializers in C# 3.0". After the study of this article, I believe you have a deeper understanding of how to understand object initializers and collection initializers in C# 3.0, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!