How to get first object out from List<Object> using Linq

Question

I have below code in c# 4.0.

//Dictionary object with Key as string and Value as List of Component type object
Dictionary>         


        

Answer 1

[0] or .First() will give you the same performance whatever happens.
But your Dictionary could contains IEnumerable instead of List, and then you cant use the [] operator. That is where the difference is huge.

So for your example, it doesn't really matters, but for this code, you have no choice to use First():

var dic = new Dictionary>();
foreach (var components in dic.Values)
{
    // you can't use [0] because components is an IEnumerable
    var firstComponent = components.First(); // be aware that it will throw an exception if components is empty.
    var depCountry = firstComponent.ComponentValue("Dep");
}