Object initializer and set initializer in C #3.0

In C #3.0, object initializers and collection initializers are simplified.CodeTo write a line of code that can be written in a few lines. In this way, we will not write a large complex LINQ expression.

I have read several articles about object initializers and collection initializers.ArticleThis is a simple example. Initialization assignment for some special scenarios is not involved, so I will sort out this blog.

Some Questions about object initializers:

Question 1: Can I assign only partial values to the object initiator? That is, do not assign values to some of the values.

Answer: Yes. Refer to the code below.

Question 2: Can the object initiator assign values to internal members? (Private Members do not need to think about it. They certainly cannot assign values .)

Answer: Yes. refer to 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)
{
Person = new person {firstname = "Scott", lastname = "Guthrie", test02 = 56 ,};
Console. writeline (person. test02 );
Console. writeline (person. Age );
Console. Readline ();
}

}

Question 3: Can the object initiator be used together with the constructor?

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

VaR cookie3 = new system. net. Cookie ("mycookie", "Jose") {comment = "a cookie "};

In the constructor, we assign a value to the cookie name and value to the comment attribute in the initialization constructor.

Question 4: Which of the following statements is executed first when the constructor assigns a value and the initialization constructor assigns a value?

For example, what is the result of the following code ??

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 writeline is test02.

Collection initializers:

Question 1: Can a null value be constructed in the Set initialization constructor?

Answer: Yes. See the following code.

Question 2: Can the set initialization constructor initialize hashtable?

Answer: Yes. At this time, two objects are used to initialize the constructor. 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
{< br> static void main (string [] ARGs)
{< br> List People = new list {< br> new person {firstname = "Scott", lastname = "Guthrie ", age = 32 },< br> new person {firstname = "bill", lastname = "Gates", test02 = 85 },< br> new person {firstname = "Susanne ", age = 32 },< br> 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 ();
}
}