Here's an example of how you might validate input:
string input=Console.ReadLine ();
if (input == "") Environment.Exit(-1);
input = input.Trim().ToLower();
string destination = "";
foreach(string dest in display_location.arrival_location)
{
if(dest.ToLower().Contains(input))
{
destination = dest;
break;
}
}
if (destination == "") Environment.Exit(-1);
switch(input)
{
case "Bangkok":
break;
case "Damascas":
break;
default:
break;
}
Notes:
1. by converting the user input to lower-case and comparing it with the destination names in lower-case, the user can have a bit more leeway to make typing mistakes in terms of case.
2. the code to exit the Console app you see here are just place-holders.
The real work in a Console app, imho, is to get a loop structure set-up so you can let the user repeat data-entry ... until they either "succeed," or they enter some character that causes the Console to terminate.