private void InitializeGrid()
        {
            dataGridView1 = new DataGridView();
            dataGridView1.Dock = DockStyle.Fill;
            dataGridView1.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight;
            dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
            dataGridView1.Parent = this;
        }

        private void LoadFirstMonth(int year)
        {
            DateTime dt = new DateTime(year, 1, 1);

            for (int i = 0; i < DateTime.DaysInMonth(year, 1); i++)
            {
                int dayNumber = i + 1;
                dt = new DateTime(year, 1, dayNumber);

                CreateColumn(dt.DayOfWeek);
            }
            int row = dataGridView1.Rows.Add();
            dataGridView1.Rows[row].HeaderCell.Value = dt.ToString("MMMM");

        }

        private void LoadGridData(int year)
        {
            
            for (int i = 0; i < 12; i++)
            {
                DateTime dt = new DateTime(year, i + 1, 1);
                int row = 0;

                if (i > 0)
                {
                    row = dataGridView1.Rows.Add();
                    dataGridView1.Rows[row].HeaderCell.Value = dt.ToString("MMMM");
                }

                for (int j = 0; j < this.dataGridView1.ColumnCount; j++)
                {                    
                    this.dataGridView1.Columns[j].Width = 25;                    
                }

                int startFrom = 0;
                for (int j = 0; j < DateTime.DaysInMonth(year, i + 1); j++)
                {
                    DateTime currentDay = new DateTime(year, i + 1, j + 1);
                    
                    //calculate start position
                    if (j == 0)
                    {
                        int month = i + 1;
                        int day = j + 1;
                        DateTime x = new DateTime(year, month, day);
                        startFrom = First(x.DayOfWeek.ToString());

                    }

                    // Create extra columns if is neded.
                    if (dataGridView1.Columns.Count <= j + startFrom)
                    {
                        CreateColumn(currentDay.DayOfWeek);
                    }

                    // Set cell value.
                    dataGridView1[j + startFrom, row].Value = currentDay.Day.ToString();
                }
            }
        }

        private int First(string n)
        {
            for (int i = 0; i < dataGridView1.Columns.Count; i++)
            {
                
                if (dataGridView1.Columns[i].Name == n)
                {
                    return i;
                }
            }
            return 0;
        }

        private void CreateColumn(DayOfWeek dayOfWeek)
        {
            string day1 = dayOfWeek.ToString();
            
            
            int columnIndex = dataGridView1.Columns.Add(dayOfWeek.ToString(), day1.Remove(3, day1.Length - 3));
            

            if (dayOfWeek == DayOfWeek.Saturday || dayOfWeek == DayOfWeek.Sunday)
            {
                dataGridView1.Columns[columnIndex].DefaultCellStyle.BackColor = ControlPaint.Light(Color.LightGray);                
            }
        }