Sudoku using Microsoft Solver Foundation

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Sudoku
{
	public class GridClass
	{

		private List<int> Squares = new List<int>(Constants.BoardSize);
		private List<List<int>> SquarePossibilities = InitPossibilities();

		public GridClass(List<int> squares)
		{
			if (Squares.Count == 0)
			{
				for (int i = 0; i < Constants.BoardSize; i++)
				{
					Squares.Add(i);
				}
			}
			Squares = squares;
		}

		public List<int> GetAllSquares()
		{
			return Squares;
		}

		public List<int> GetRow(int rowNumber)
		{
			List<int> row = new List<int>(9);
			for (int i = 0; i < 9; i++)
			{
				row.Add(Squares[i + (rowNumber * 9)]);
			}
			return row;
		}

		public List<int> GetColumn(int columnNumber)
		{
			List<int> column = new List<int>(9);
			for (int i = 0; i < 9; i++)
			{
				column.Add(Squares[(i * 9) + columnNumber]);
			}
			return column;
		}

		public List<int> GetRegion(int regionNumber)
		{
			List<int> region = new List<int>(9);
			int verticalOffSet = (regionNumber / 3) * 3;
			for (int i = 0 + verticalOffSet; i < 3 + verticalOffSet; i++)
			{
				List<int> row = GetRow(i);
				int horizontalOffSet = (regionNumber % 3) * 3;
				for (int j = 0 + horizontalOffSet; j < 3 + horizontalOffSet; j++)
				{
					region.Add(row[j]);
				}
			}
			return region;
		}

		private static List<List<int>> InitPossibilities()
		{
			List<List<int>> list = new List<List<int>>();
			for (int i = 0; i < 80; i++)
			{
				list.Add(new List<int>() {1,2,3,4,5,6,7,8,9});
			}
			return list;
		}

	}
}