C# string does not contain possible?

Question

This should do the trick for you.

For one word:

if (!string.Contains("One"))

For two words:

if (!(string.Contains("One") && string.Contains("Two")))

You should put all your words into some kind of Collection or List and then call it like this:

var searchFor = new List<string>();
searchFor.Add("pineapple");
searchFor.Add("mango");

bool containsAnySearchString = searchFor.Any(word => compareString.Contains(word));

If you need to make a case or culture independent search you should call it like this:

bool containsAnySearchString = 
   searchFor.Any(word => compareString.IndexOf
     (word, StringComparison.InvariantCultureIgnoreCase >= 0);

So you can utilize short-circuiting:

bool containsBoth = compareString.Contains(firstString) && 
                    compareString.Contains(secondString);

Use Enumerable.Contains function:

var result =
    !(compareString.Contains(firstString) || compareString.Contains(secondString));

bool isFirst = compareString.Contains(firstString);
bool isSecond = compareString.Contains(secondString );

Option with a regexp if you want to discriminate between Mango and Mangosteen.

var reg = new Regex(@"\b(pineapple|mango)\b", 
                       RegexOptions.IgnoreCase | RegexOptions.Multiline);
   if (!reg.Match(compareString).Success)
      ...