How to set timeout for a line of c# code [duplicate]

You can use the Task Parallel Library. To be more exact, you can use Task.Wait(TimeSpan):

using System.Threading.Tasks;

var task = Task.Run(() => SomeMethod(input));
if (task.Wait(TimeSpan.FromSeconds(10)))
    return task.Result;
else
    throw new Exception("Timed out");