list互转datatable 支持Nullable转换

 

        /// <summary>
        /// list转datatable
        /// </summary>
        /// <param name="list"></param>
        /// <returns></returns>
        public static DataTable ListToTable(IList list)
        {
            DataTable dt = new DataTable();
            if (list != null)
            {
                //通过反射获取list中的字段 
                System.Reflection.PropertyInfo[] p = list[0].GetType().GetProperties();
                foreach (System.Reflection.PropertyInfo pi in p)
                {
                    var colType = pi.PropertyType;
                    if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>)))
                    {
                        colType = colType.GetGenericArguments()[0];
                    }

                    dt.Columns.Add(pi.Name, colType);
                }
                for (int i = 0; i < list.Count; i++)
                {
                    IList TempList = new ArrayList();
                    //将IList中的一条记录写入ArrayList
                    foreach (System.Reflection.PropertyInfo pi in p)
                    {
                        object oo = pi.GetValue(list[i], null);
                        TempList.Add(oo);
                    }
                    object[] itm = new object[p.Length];
                    for (int j = 0; j < TempList.Count; j++)
                    {
                        itm.SetValue(TempList[j], j);
                    }
                    dt.LoadDataRow(itm, true);
                }
            }
            return dt;
        }

 

 /// <summary>  
        /// DataTable转化为List集合  
        /// </summary>  
        /// <typeparam name="T">实体对象</typeparam>  
        /// <param name="dt">datatable表</param>  
        /// <param name="isStoreDB">是否存入数据库datetime字段，date字段没事，取出不用判断</param>  
        /// <returns>返回list集合</returns>  
        public static List<T> TableToList<T>(DataTable dt, bool isStoreDB = true)
        {
            List<T> list = new List<T>();
            Type type = typeof(T);
            List<string> listColums = new List<string>();
            foreach (DataRow row in dt.Rows)
            {
                PropertyInfo[] pArray = type.GetProperties(); //集合属性数组  
                T entity = Activator.CreateInstance<T>(); //新建对象实例  
                foreach (PropertyInfo p in pArray)
                {
                    if (!dt.Columns.Contains(p.Name) || row[p.Name] == null || row[p.Name] == DBNull.Value)
                    {
                        continue;  //DataTable列中不存在集合属性或者字段内容为空则，跳出循环，进行下个循环  
                    }
                    if (isStoreDB && p.PropertyType == typeof(DateTime) && Convert.ToDateTime(row[p.Name]) < Convert.ToDateTime("1753-01-01"))
                    {
                        continue;
                    }
                    try
                    {
                        var obj = Convert.ChangeType(row[p.Name], p.PropertyType);//类型强转，将table字段类型转为集合字段类型  
                        p.SetValue(entity, obj, null);
                    }
                    catch (Exception)
                    {
                        // throw;  
                    }
                    //if (row[p.Name].GetType() == p.PropertyType)  
                    //{  
                    //    p.SetValue(entity, row[p.Name], null); //如果不考虑类型异常，foreach下面只要这一句就行  
                    //}  
                    //object obj = null;  
                    //if (ConvertType(row[p.Name], p.PropertyType,isStoreDB, out obj))  
                    //{                      
                    //    p.SetValue(entity, obj, null);  
                    //}  
                }
                list.Add(entity);
            }
            return list;
        }