I prefer using DateTime.TryParseExact to help ensure the month and day are never transposed due to an unexpected difference between regional settings in my local development environment and regional settings in the environment where the code might eventually run (e.g. a remote web server).
If the input string always follows the same pattern (e.g. "yyyy-MM-DDtHH:mm:ss") then my preferred solution looks like this:
var culture = new CultureInfo("en-US");
var input = "2015-06-01t00:00:00";
if ( DateTime.TryParseExact(input, @"yyyy-MM-dd\tHH:mm:ss", culture, DateTimeStyles.None, out parsed ) )