Remove Duplicate Records from a string

Remove Duplicate Records from a string

public string RemoveDuplicates(string items)
    {
        StringBuilder Result = new StringBuilder();


        String[] newArray = items.Split(',');


        for (int i = 0; i < newArray.Length; i++)
        {
            if (Result.ToString().IndexOf(newArray[i]) == -1)
            {
                Result.Append(newArray[i].ToString()).Append(",");
            }
        }
        return Result.ToString().Substring(0, Result.ToString().LastIndexOf(','));

    }


EXample : Value=Apple, Banana,Cherry, Apple,Banana

Value=RemoveDuplicates(Value);

Result: Apple, Banana, Cherry