C#

private void dg_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    DataGridView dg = sender as DataGridView;

    DataGridViewComboBoxColumn combo = dg.Columns[0] as DataGridViewComboBoxColumn;
    LogManager.Instance.Logger("Policy SI").Info("Edit Control Showing");
    if (dg.CurrentCellAddress.X == combo.DisplayIndex)
    {
        LogManager.Instance.Logger("Policy SI").Info("We have a combo");
        cb = e.Control as ComboBox;
        if (cb != null)
        {
            cb.SelectedIndexChanged -= new EventHandler(cb_SelectedIndexChanged);
            cb.DropDownStyle = ComboBoxStyle.DropDown;
            cb.SelectedIndexChanged += new EventHandler(cb_SelectedIndexChanged);
        }
    }
}

private void cb_SelectedIndexChanged(object sender, EventArgs e)
{
    originalDescription = cb.Text;
}

private void dg_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
        {
            
            DataGridView dgB = sender as DataGridView;
            if (dgB.CurrentRow.IsNewRow == true) 
            {
                LogManager.Instance.Logger("Policy SI").Info("New Row ");
                return; 
            }

            if (e.ColumnIndex == 0)
            {
                LogManager.Instance.Logger("Policy SI").Info("Validating Col 1");
                string newDescription = string.Empty;
                newDescription = e.FormattedValue.ToString();

                quoteTemplate = valuablesBinding.FirstOrDefault(p => p.Description == originalDescription || p.Description == policySumInsured.Description);
                
                //Attempted here to deepclone the object from the valuables bindinglist
                //quoteTemplate = quoteTemplateNewDescription.DeepClone();  

                 //Here with these 3 lines it will then fire the selectedindexchanged 
                 //event that is on the combobox
                policySumInsured.ItemNo = (int)quoteTemplate.ItemNo;
                policySumInsured.Description = quoteTemplate.Description;
                policySumInsured.Section = quoteTemplate.Section;
            }
            else
            {
                if (e.ColumnIndex == 1)
                {
                    //Other validation routine here
                }
            }     
        }