Add different data in same column in DataTable in C#

Question

I want to add two different Values in Same column in DataTable.

row0["sessionID"] = ss.session_id;
row0["sessionID"] = se.session_id;

Scenario is I have to sessions 2015-16 and 2016-17 they both have a start date and a end date and ID. I want if start date of 2nd session occurs than ID of 2nd session must be added into sessionIDcolumn.

For Example: the ID of session 2015-16 is 50 and the ID of session 2016-17 is 70 then the DataTable must be look like this:

SessionID       Session Date
____________________________
 50             2015-10-01
 50             2015-11-01
 50             2015-12-01
 50             2016-01-01
 50             2016-02-28
 70             2016-03-01
 70             2016-04-01
 70             2016-05-01
 .                  .
 .                  .
 70             2017-03-31

Date is Adding fine but I am unable to add Session ID. How can I add it?

Here is my complete code:

  var sessionsFrom = (from o in _session.GetAll()
                        where o.session_name == ddl_SessionFrom.SelectedItem.Text
                        && o.branch_id == Convert.ToInt32(ddl_search_branch.SelectedValue)
                        select o).ToArray();

        var sessionsTo = (from o in _session.GetAll()
                            where o.session_id == Convert.ToInt32(ddl_SessionTo.SelectedValue)
                            && o.branch_id == Convert.ToInt32(ddl_search_branch.SelectedValue)
                            select o).ToArray();


        DataTable dt = new DataTable();
        dt.Columns.Add("id").DataType = typeof(Int32);
        dt.Columns.Add("SessionFrom"); 
        dt.Columns.Add("SessionTo");
        dt.Columns.Add("Month");
        dt.Columns.Add("totalStudent").DataType = typeof(Int32);
        dt.Columns.Add("totalAdmission").DataType = typeof(Int32);
        dt.Columns.Add("totLefts").DataType = typeof(Int32);
        dt.Columns.Add("sessionID").DataType = typeof(Int32);

        foreach (var ss in sessionsFrom)
            foreach(var se in sessionsTo)
        {

            var row0 = dt.NewRow();               

            row0["totalStudent"] = totalStudent;
            row0["SessionFrom"] = ss.session_name;
            row0["SessionTo"] = se.session_name;
            row0["sessionID"] = ss.session_id;
            row0["sessionID"] = se.session_id;               

            id = id + 1;
            row0["id"] = id;
            ts = totalStudent;
            dt.Rows.Add(row0);

            for (DateTime i = ss.session_startdate; i < se.session_enddate; i = i.AddMonths(1))
            {
                int a = i.Month;
                int b = i.Year;
                var row = dt.NewRow();

                row["SessionFrom"] = ss.session_name;
                row["SessionTo"] = se.session_name;
                row["sessionID"] = se.session_id;
                .
                .
                .

Answer 1

The following code creates a DataTable which reach your example table in your question:

//Help Method to iterate over Dates
public IEnumerable<DateTime> EachMonth(DateTime from, DateTime thru)
{
    for(var month = from.Date; month.Date <= thru.Date; month = month.AddMonth(1))
        yield return month;
}

DataTable dt = new DataTable();
dt.Columns.Add("SessionID").DataType = typeof(Int32);
dt.Columns.Add("SessionDate").DataType = typeof(DateTime);

// Iterate over all dates from 01.01.2015 to 01.03.2017
foreach (DateTime date in EachMonth(new DateTime(2015,1,1), new DateTime(2017,3,1))
{
   DataRow row = dt.NewRow();

   // Check if the magic Date is reached. After this ID jumps to 70
   if (date.CompareTo(new DateTime(2016, 2, 28)) <= 0)
   {
      row["SessionID"] = 50;
   }
   else
   {
      row["SessionID"] = 70;
   }

   row["SessionDate"] = date;
   dt.Rows.Add(row);
}

This is the hardcoded way to reach your table preferred in your question.

I hope this helps you. You simple add one row each month. If the month is higher then value X your Id is set to another value.