The contains method can be used if you want to check if a string
contains certain characters. It’s fairly simple to use. Here’s an example:
After the contains method, you type a pair of round brackets. In between the
round brackets, you type the text you’re checking for. In our code, we’re using
an if statement. If it’s true that the string contains a “-” character,
then some code can be executed.
A more complicated, and probably more useful, method that you’ll need to know
about is called IndexOf. That’s the next lesson.
Kaynak : https://www.homeandlearn.co.uk/csharp/csharp_s8p3.html ‘sitesinden alıntı