how do print first month and after days of month

See more:

C#

hi all

for create a bill i want print first month and then days base on below syntax :

we have a 2 date : 1- start date 2- end date

i want print month and daye between this dates ...

suppose start date is 2009/05/12 and end date is 2013/03/11

i want first print 18 month between first and end date like this (start one month after start date 2012/06/12):

2009/06/12
2009/07/12
2009/08/12
2009/09/12
2009/10/12
.
.
.
2010/08/12
2010/09/12
2010/10/12

and after it print base on days like
2010/10/13
2010/10/14
2010/10/15
.
.
.
until end date (2013/03/11)

how do i this ?

i use this code :

private void showbill_Load(object sender, EventArgs e)
    {

        lbl_user_fullname.Text  = Class_Variables.bill_user_firstname + " " + Class_Variables.bill_user_lastname;
        lbl_debt_price.Text = Class_Variables.bill_dept_price;
        lbl_peyments_count.Text = Class_Variables.bill_debt_peyments_count;

        string debt_year = Class_Variables.bill_dept_date.Substring(0, 4);
        string debt_month = Class_Variables.bill_dept_date.Substring(5,2);
        string debt_day = Class_Variables.bill_dept_date.Substring(8,2);

        string current_date_year = Class_Variables.bill_current_date.Substring(0, 4);
        string current_date_month = Class_Variables.bill_current_date.Substring(5, 2);
        string current_date_day = Class_Variables.bill_current_date.Substring(8, 2);



        dtp_farsi.CustomFormat = "y/MM/dd";
        dtp_farsi.Format = BehComponents.DateTimePickerX.FormatDate.Custom;
        dtp_farsi.SetSelectedDate(BehComponents.CalendarTypes.Persian, Convert.ToInt32(debt_year), Convert.ToInt32(debt_month), Convert.ToInt32(debt_day));

        dtp_farsi2.CustomFormat = "y/MM/dd";
        dtp_farsi2.Format = BehComponents.DateTimePickerX.FormatDate.Custom;
        dtp_farsi2.SetSelectedDate(BehComponents.CalendarTypes.Persian, Convert.ToInt32(current_date_year), Convert.ToInt32(current_date_month), Convert.ToInt32(current_date_day));

        int debt_price = Convert.ToInt32( Class_Variables.bill_dept_price);
        int peyments_count = Convert.ToInt32(Class_Variables.bill_debt_peyments_count);

        string todaydate = dtp_farsi.Text;

        //colnames names
        string[] colnames = new string[5];

        colnames[0] = "no";
        colnames[1] = "date";
        colnames[2] = "delay days";
        colnames[3] = "delay percent";
        colnames[4] = "delay price";
        //--------------------------------------------------

        const int dim = 1000;


        string[,] array = new string[dim, 5];
        int peyment_count = 1;
        TimeSpan ts = new TimeSpan();
        TimeSpan ts2 = new TimeSpan();
        int daydiff = 31;
        int daydiff2 = 0;

        int while_loop_counter=0;


        while(daydiff > 30)
        {
            ts = dtp_farsi2.GetSelectedDateInPersianDateTime().Subtract(dtp_farsi.GetSelectedDateInPersianDateTime().AddMonths(while_loop_counter+1));
            daydiff = ts.Days;

            for (int j = 0; j < 5; j++)
            {
                if (j == 0)
                {
                    array[while_loop_counter, j] = (while_loop_counter + 1).ToString();
                }
                else
                {
                    //Column #1
                    array[while_loop_counter, 1] = dtp_farsi.GetSelectedDateInPersianDateTime().AddMonths(peyment_count).ToStringFormat("y/MM/dd");

                    //Column #2
                    ts2 = dtp_farsi2.GetSelectedDateInPersianDateTime().Subtract(dtp_farsi.GetSelectedDateInPersianDateTime().AddMonths(peyment_count));
                    daydiff2 = ts2.Days;
                    array[while_loop_counter, 2] = daydiff2.ToString();

                    //Column #3
                    switch (while_loop_counter + 1)
                    {
                        case 1:
                        case 2:
                        case 3:
                        case 4:
                        case 5:
                        case 6:
                        case 7:
                        case 8:
                        case 9: array[while_loop_counter, 3] = 26.ToString();
                            break;

                        case 10:
                        case 11:
                        case 12: array[while_loop_counter, 3] = 24.ToString();
                            break;

                        case 13:
                        case 14:
                        case 15:
                        case 16: array[while_loop_counter, 3] = 22.ToString();
                            break;

                        case 17:
                        case 18: array[while_loop_counter, 3] = 20.ToString();
                            break;

                        default: array[while_loop_counter, 3] = 28.ToString();
                            break;
                    }



                    //Column #4

                    if (while_loop_counter <= 18)
                    {
                        array[while_loop_counter, 4] = (((debt_price / peyments_count) * Convert.ToInt64(array[while_loop_counter, 3]) * Convert.ToInt64(array[while_loop_counter, 2])) / 36500).ToString();
                    }
                    else
                    {
                        array[while_loop_counter, 4] = (((debt_price / peyments_count) * Convert.ToInt64(array[while_loop_counter, 3]) * Convert.ToInt64(array[while_loop_counter, 2])) / 36500).ToString();
                    }


                }

            }
            peyment_count++;

        while_loop_counter++;
    }



        dgv_bill.DataSource = new Mommo.Data.ArrayDataView(array, colnames);



        }

please help me ...

thanks a lot