SharePoint 获取Lookup 字段的值

获取某个List里的Lookup字段的值是很普遍的事，那么我们将它封装起来

获取Lookup字段值的方法：

        /// <summary>
        /// To get lookup field Id or Value
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="item"></param>
        /// <param name="fieldName"></param>
        /// <param name="defaultValue"></param>
        /// <param name="getValueType">0:return Id, 1:return Value</param>
        /// <returns></returns>
        public static T GetLookupField<T>(this SPListItem item, string fieldName, int getValueType, T defaultValue)
        {
            fieldName = fieldName.Replace(" ", ConstVariables.blankSpicalCode);

            if (item[fieldName] == null)
            {
                return defaultValue;
            }

            var itemElements = Regex.Split(item[fieldName].ToString(), ";#", RegexOptions.IgnoreCase);

            if (itemElements.Length >= 2)
            {
                return ConvertTo<T>(itemElements[getValueType], defaultValue);
            }
            else
            {
                return defaultValue;
            }
        }

调用该方法： <oldPlan是SPListItem>
1. 获取Lookup的ID: 

oldPlan.GetLookupField<int>(ConstVariables.PRColumns.ColumnStatus, 0, 0);

2. 获取Lookup的Value:

oldPlan.GetLookupField<string>(ConstVariables.AllBGProfileColumns.ColumnBGName, 1, string.Empty)