Difference between the implementation of var in Javascript and C#

Question

I would like to ask a theoretical question. If I have, for example, the following C# code in Page_load:

cars = new carsModel.carsEntities();

var mftQuery =          


        

Answer 1

var in C# is dynamic at design time but staticly typed at compile time. You will see that if you do:

var mftQuery = from mft in cars.Manufacturers
    where mft.StockHeaders.Any(sh=> sh.StockCount>0) 
    orderby mft.CompanyName
    select new {mft.CompanyID, mft.CompanyName};

and then:

mftQuery = "Hello world!";

It will not compile and complain about missmatching types even though you didn't specify any type.

This is a useful productivity enhancement because you can easily change return types to similar types without breaking anything and it is easier to write. A stupid example:

foreach(var animal in GetCats()){
   Console.WriteLine(animal.Owner);
}

could be changed to:

foreach(var animal in GetDogs()){
   Console.WriteLine(animal.Owner);
}