How to enable gridview column for editing in C#?

[Brian Connelly]

I have a datagridview populated by the following code:

  if (hasTime == true)
            {
 
                string hourQuery = string.Format("SELECT contact.contactID, contact.firstName, contact.lastName, hours.hoursWorked" +
                           " FROM contact INNER JOIN hours ON contact.contactID=hours.contactID WHERE hours.fiscalYearID ={0}", selectedYearID.ToString());
                cmd.CommandText = hourQuery;
                cmd.Connection.Open();
                var dr = cmd.ExecuteReader();
                if (dr.HasRows == true)
                {
                    DataTable cHours = new DataTable();
                    cHours.Load(dr);
                    bindings.DataSource = cHours;
                    dgvTime.DataSource = bindings;
                    cmd.Connection.Close();
                }
                foreach (DataGridViewColumn column in dgvTime.Columns)
                {
                    if (column.HeaderText == "contactID") { column.HeaderText = "ID"; column.ReadOnly = true; column.Visible = false; column.Width = 50; }
                    if (column.HeaderText == "firstName") { column.HeaderText = "First"; column.Width = 150; column.ReadOnly = true; }
                    if (column.HeaderText == "lastName") { column.HeaderText = "Last"; column.Width = 150; column.ReadOnly = true; }
                    if (column.HeaderText == "hoursWorked") { column.HeaderText = "Annual Hours"; column.Width = 150; column.ReadOnly = true; }
                }
 

How do I allow hhe column hoursWorked to be editable? When I change column.ReadOnly to false, it fails.

Any help or insight would be grsatly appreciated.