public static string GetCustomProperty(this Excel.Workbook book, string propertyName)        {            //string strResult = string.Empty;            //Office.DocumentProperties pros = (Office.DocumentProperties)book.CustomDocumentProperties;            //strResult = GetCustomProperty(pros, propertyName);            //if (!string.IsNullOrEmpty(strResult))            //{            //    return strResult;            //}            //int index = 1;            //while (true)            //{            //    string pName = propertyName + index++.ToString();            //    string pValue = http://www.mamicode.com/GetCustomProperty(pros, pName);>//    if (string.IsNullOrEmpty(pValue))            //    {            //        break;            //    }            //    else            //    {            //        strResult += pValue;            //    }            //}            //return strResult;            string strResult = string.Empty;            var bookType = book.GetType();            var pros = bookType.InvokeMember("CustomDocumentProperties", System.Reflection.BindingFlags.GetProperty, null, book, null);            var propertiesType = pros.GetType();            var enumerator = (IEnumerator)propertiesType.InvokeMember("GetEnumerator", System.Reflection.BindingFlags.InvokeMethod, null, pros, null);            Func<string, string> getPropertyValue = http://www.mamicode.com/new Func<string, string>(s =>            {                string strValue = http://www.mamicode.com/string.Empty;                enumerator.Reset();                while (enumerator.MoveNext())                {                    var p = enumerator.Current;                    var name = p.GetType().InvokeMember("Name", System.Reflection.BindingFlags.GetProperty, null, p, null);                    if (name != null && name.ToString().Equals(propertyName))                    {                        return (string)p.GetType().InvokeMember("Value", System.Reflection.BindingFlags.GetProperty, null, p, null);                    }                }                return strValue;            });            strResult = getPropertyValue(propertyName);            if (!string.IsNullOrEmpty(strResult))            {                return strResult;            }            int index = 1;            while (true)            {                string pName = propertyName + index++.ToString();                string pValue =http://www.mamicode.com/ getPropertyValue(pName);                if (string.IsNullOrEmpty(pValue))                {                    break;                }                else                {                    strResult += pValue;                }            }            return strResult;        }


注掉的代码，在多线程操作中会出错