public static partial class StringExtensions
        public static bool HasMultipleInstancesOf(this string input, char charToFind)

            if ((string.IsNullOrEmpty(input)) || (input.Length == 0) || (input.IndexOf(charToFind) == 0))
                return false;

            if (input.IndexOf(charToFind) != input.LastIndexOf(charToFind))
                return true;

            return false;
string myStr1= "Hello.World.txt";
string myStr2= "Hello World";

bool hasMultPeriods = myStr1.HasMultipleInstancesOf('.'); //returns true
bool hasMultSpaces = myStr2.HasMultipleInstancesOf(' '); //returns false


Determines whether a string has multiple occurrences of a particular character. May be helpful when parsing file names, or ensuring a particular string has already contains a given character. This may be extended to use strings, rather than a char.


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