DataGridViewComboBoxCell not working right

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C#

DataGridView

I have a very simple sample application below. This is for Windows Forms, and should have a matching for created in Designer with a DataGridView that has two columns: Name, and Department. Department is a DataGridViewComboBoxCell.

The grid lists data as expected, and the combo-box list its items as expected. However, I cannot get the data selected in the combo-box tied to the DataBoundItem of the grid. For example, when the app first starts, my only Person object has a DepartmentID = 2, which matches a value in the combo-box, but nothing is selected in the combo-box. When something is selected in the combo-box, it does not get reflected in the Person object.

There is a commented-out line of code for setting ValueMember, but this causes a "Field called DeptID does not exist" error.

It is important that both data sets are ArrayList and not DataTable.

How do I complete the binding between row data and combo-box selection?

--- Full project code is below ---

using System;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace TestApp
{
	public partial class Form1 : Form
	{
		private ArrayList personList = new ArrayList();
		private ArrayList deptList = new ArrayList();
		BindingSource m_BindSource = new BindingSource();
		public Form1()
		{
			InitializeComponent();
		}
		private void Form1_Load(object sender, EventArgs e)
		{
			personList.Add(new Person("Tim", 2));
			deptList.Add(new Department("A", 1));
			deptList.Add(new Department("B", 2));
			deptList.Add(new Department("C", 3));
			DataGridViewComboBoxCell cell = (DataGridViewComboBoxCell)grid1.Columns[1].CellTemplate;
			cell.DataSource = deptList;
			cell.DisplayMember = "DeptName";
			//cell.ValueMember = "DeptID";	// "Field called DeptID does not exist"
			try
			{
				m_BindSource.DataSource = null;
				m_BindSource.DataSource = personList;
				grid1.DataSource = m_BindSource;
			}
			catch (Exception ex)
			{
				ex.GetType();
				MessageBox.Show(ex.Message);
			}
		}
	}
	public class Person
	{
		public Person(String name, int deptID)
		{
			PersonName = name;
			DepartmentID = deptID;
		}
		private String m_PersonName;
		public String PersonName
		{
			get { return m_PersonName; }
			set { m_PersonName = value; }
		}
		private int m_DepartmentID;
		public int DepartmentID
		{
			get { return m_DepartmentID; }
			set { m_DepartmentID = value; }
		}
	}
	public class Department
	{
		public Department(String name, int deptID)
		{
			DeptName = name;
			DepartmentID = deptID;
		}
		private String m_DeptName;
		public String DeptName
		{
			get { return m_DeptName; }
			set { m_DeptName = value; }
		}
		private int m_DepartmentID;
		public int DepartmentID
		{
			get { return m_DepartmentID; }
			set { m_DepartmentID = value; }
		}
	}
}