How to get first object out from List using Linq

Try:

var firstElement = lstComp.First();

You can also use FirstOrDefault() just in case lstComp does not contain any items.

http://msdn.microsoft.com/en-gb/library/bb340482(v=vs.100).aspx

Edit:

To get the Component Value:

var firstElement = lstComp.First().ComponentValue("Dep");

This would assume there is an element in lstComp. An alternative and safer way would be…

var firstOrDefault = lstComp.FirstOrDefault();
if (firstOrDefault != null) 
{
    var firstComponentValue = firstOrDefault.ComponentValue("Dep");
}