从源字符串中查找多个索引

    var indexs = "Prashant".MultipleIndex('a');//Extension Method's Class    public static class Extensions    {         static int i = 0;         public static int[] MultipleIndex(this string StringValue, char chChar)         {var indexs = from rgChar in StringValue  where rgChar == chChar && i != StringValue.IndexOf(rgChar, i + 1)  select new { Index = StringValue.IndexOf(rgChar, i + 1), Increament = (i = i + StringValue.IndexOf(rgChar)) }; i = 0; return indexs.Select(p => p.Index).ToArray<int>();          }    }