Excel Fill Handle function call

[schebotar]

Hello
I'm playing with simple function returning random double

        [ExcelFunction]
        public static double Random()
        {
            return new Random().NextDouble();
        }

This works nice on =Random() in cell or Ctrl + C,V cell with function.
But when I try to copy it with fill handle I just get one random number

Is it possible to call function on each row filled with fill handle?

[govert]

If you mark your function as volatile with [ExcelFunction(IsVolatile=true)] it will recalculate and return a new value every time the sheet calculates, just like the built-in =RAND() function.
To get a good distribution of random numbers, you should also create one instance of the .NET 'Random' class, and use that one repeatedly.

       static Random _rand = new Random();

       [ExcelFunction(IsVolatile=true)]
        public static double Random()
        {
            return _rand.NextDouble();
        }