Initialization of list in class for availability from functions

Question

I want initialize list with collection initializer values in class to make it available to use from separate functions:

public Form1()
{
    InitializeComponent();
}

List<string> list = new List<string>() {"one", "two", "three"}; 

What is a difference of list with brackets and without, which one is proper for this case:

List<string> list = new List<string> {"one", "two", "three"}; 

Answer 1

Calling

List<string> list = new List<string> {"one", "two", "three"}; 

is just a shorthand and implicitly calls the default constructor:

List<string> list = new List<string>() {"one", "two", "three"}; 

Also see the generated IL code, it is the same:

List<string> list = new List<string>() {"one"}; 
List<string> list2 = new List<string> {"one"}; 

becomes:

IL_0001:  newobj     instance void class [mscorlib]System.Collections.Generic.List`1<string>::.ctor()
IL_0006:  stloc.2
IL_0007:  ldloc.2
IL_0008:  ldstr      "one"
IL_000d:  callvirt   instance void class [mscorlib]System.Collections.Generic.List`1<string>::Add(!0)
IL_0012:  nop
IL_0013:  ldloc.2
IL_0014:  stloc.0

IL_0015:  newobj     instance void class [mscorlib]System.Collections.Generic.List`1<string>::.ctor()
IL_001a:  stloc.3
IL_001b:  ldloc.3
IL_001c:  ldstr      "one"
IL_0021:  callvirt   instance void class [mscorlib]System.Collections.Generic.List`1<string>::Add(!0)
IL_0026:  nop
IL_0027:  ldloc.3
IL_0028:  stloc.1

You see that the {} notation is just syntactical sugar that first calls the default constructor and then adds every element inside the {} using the List<T>.Add() method. So your code is equivalent to:

List<string> list = new List<string>();
list.Add("one");
list.Add("two");
list.Add("three");