C#-Code

using System;
using System.Collections.Generic;

namespace Sudoku
{
	class Program
	{
		static int[,] grid = new int[9, 9];
		static Random rnd = new Random();
		static void Main(string[] args)
		{
			Console.WriteLine("Generating grid ...");
			while (!GenerateGrid())
			{

			}
			Console.Clear();
			ShowGrid();
			Console.ReadKey();
		}

		private static void ShowGrid()
		{
			for (int y = 0; y < 9; y++)
			{
				for (int x = 0; x < 9; x++)
				{
					Console.Write(grid[x, y]);
					if((x+1) % 3 == 0)
						Console.Write("|");
				}
				Console.WriteLine("");
				if ((y + 1) % 3 == 0)
					Console.WriteLine("------------");
			}
		}

		private static bool GenerateGrid()
		{
			grid = new int[9, 9];
			for (int i = 0; i < 9; i++)
			{
				grid[0, i] = rnd.Next(9)+1;
			}

			for (int y = 0; y < 9; y++)
			{
				for (int x = 1; x < 9; x++)
				{
					List<int> availableNumbers = Numbers();
					for (int i = 0; i< 9; i++)
					{
						if (grid[i, y] != 0)
						{
							availableNumbers.Remove(grid[i, y]);
						}
					}

					for (int i = 0; i < 9; i++)
					{
						if (grid[x, i] != 0)
						{
							availableNumbers.Remove(grid[x, i]);
						}
					}

					if (availableNumbers.Count == 0)
					{
						return false;
					}
					grid[x, y] = availableNumbers[rnd.Next(availableNumbers.Count)];
				}
			}
			return true;
		}

		private static List<int> Numbers()
		{
			List<int> numbers = new List<int>();
			for (int i = 0; i < 9; i++)
			{
				numbers.Add(i + 1);
			}
			return numbers;
		}
	}
}