----------
20180926
var
local var type inference


Beginning in Visual C# 3.0, variables that are declared at method scope can have an implicit "type" var. An implicitly typed local variable is strongly typed just as if you had declared the type yourself, but the compiler determines the type. The following two declarations of i are functionally equivalent: 

var i = 10; // Implicitly typed. 
int i = 10; // Explicitly typed. 

Note: C# 3.0 is from visual studio 2008.

----------
// Example #1: var is optional because
// the select clause specifies a string
string[] words = { "apple", "strawberry", "grape", "peach", "banana" };
var wordQuery = from word in words
                where word[0] == 'g'
                select word;

// Because each element in the sequence is a string, 
// not an anonymous type, var is optional here also.
foreach (string s in wordQuery)
{
    Console.WriteLine(s);
}

// Example #2: var is required because
// the select clause specifies an anonymous type
var custQuery = from cust in customers
                where cust.City == "Phoenix"
                select new { cust.Name, cust.Phone };

// var must be used because each item 
// in the sequence is an anonymous type
foreach (var item in custQuery)
{
    Console.WriteLine("Name={0}, Phone={1}", item.Name, item.Phone);
}

----------
Example 3:

var result = new[] {new { ID=101, Name="Honda"}, new {ID = 102, Name="YAMAHA" }}

foreach (var item in result)
{
    Console.WriteLine("ID={0}, Name={1}", item.ID, item.Name);
}