Possible Duplicate:
Remove duplicates from array
How to get distinct values from an array in C#
Possible Duplicate:
Remove duplicates from array
How to get distinct values from an array in C#
You could use the .Distinct() extension method.
var collectionWithDistinctElements = oldArray.Distinct().ToArray();
 
    
    Use the Distinct method in LINQ.
See http://msdn.microsoft.com/en-us/library/bb348436.aspx
            List<int> ages = new List<int> { 21, 46, 46, 55, 17, 21, 55, 55 };
            IEnumerable<int> distinctAges = ages.Distinct();
            Console.WriteLine("Distinct ages:");
            foreach (int age in distinctAges)
            {
                Console.WriteLine(age);
            }
            /*
             This code produces the following output:
             Distinct ages:
             21
             46
             55
             17
            */
 
    
    Distinct should suffice your problem, but if you are doing this on custom object you will need to implement IEquatable<T> and will need to override GetHashCode() method to make it work.
