How can I check if a string contains a character in C#?

Question

Is there a function I can apply to a string that will return true of false if a string contains a character.

I have strings with one or more character options such

Answer 1

It will be hard to work in C# without knowing how to work with strings and booleans. But anyway:

        String str = "ABC";
        if (str.Contains('A'))
        { 
            //...
        }

        if (str.Contains("AB"))
        { 
            //...
        }