/// <summary>
        /// Reads new values entered by the user for the field (as id)
        /// </summary>
        /// <param name="control">Parent control that controls were added to in the CreateEditControl() method</param>
        /// <param name="configurationValues">The configuration values.</param>
        /// <returns></returns>
        public override string GetEditValue(System.Web.UI.Control control, Dictionary <string, ConfigurationValue> configurationValues)
        {
            bool allowMultiSelect = false;

            if (configurationValues != null &&
                configurationValues.ContainsKey(CONFIG_GROUP_PICKER_ALLOW_MULTI_SELECT) &&
                configurationValues[CONFIG_GROUP_PICKER_ALLOW_MULTI_SELECT] != null)
            {
                allowMultiSelect = configurationValues[CONFIG_GROUP_PICKER_ALLOW_MULTI_SELECT].Value.AsBoolean();
            }

            CheckinGroupPicker picker = control as CheckinGroupPicker;

            if (picker != null)
            {
                if (allowMultiSelect)
                {
                    return(string.Join("|", picker.SelectedGroups.Select(g => g.Guid.ToString())));
                }
                else
                {
                    if (picker.SelectedGroup != null)
                    {
                        return(picker.SelectedGroup.Guid.ToString());
                    }
                }
            }
            return(null);
        }
        /// <summary>
        /// Creates the control(s) necessary for prompting user for a new value
        /// </summary>
        /// <param name="configurationValues">The configuration values.</param>
        /// <param name="id"></param>
        /// <returns>
        /// The control
        /// </returns>
        public override System.Web.UI.Control EditControl(Dictionary <string, ConfigurationValue> configurationValues, string id)
        {
            bool allowMultiSelect = false;

            if (configurationValues != null &&
                configurationValues.ContainsKey(CONFIG_GROUP_PICKER_ALLOW_MULTI_SELECT) &&
                configurationValues[CONFIG_GROUP_PICKER_ALLOW_MULTI_SELECT] != null)
            {
                allowMultiSelect = configurationValues[CONFIG_GROUP_PICKER_ALLOW_MULTI_SELECT].Value.AsBoolean();
            }

            CheckinGroupPicker groupPicker = new CheckinGroupPicker {
                ID = id, AllowMultiSelect = allowMultiSelect
            };

            return(groupPicker);
        }