C#使用泛型方法将Datatable转换成List对象集合

 在项目中遇到需要将Datatable转换成对象的需求，通过dr[0]取下标这种获取，如果数据的顺序发生了改变则需要改变全部，工作量大

foreach (DataRow dr in dt.Rows)
            {
                CheckDetail info = new CheckDetail();
                info.org_id = dr[0].ToString();
                info.am_line_id = dr[1].ToString();
                info.component = dr[2].ToString();
                info.standard = dr[3].ToString();
                info.frequency = dr[4].ToString();
                info.status_code = dr[5].ToString();
                info.status_name = dr[6].ToString();
                info.activity_type = dr[7].ToString();
                info.activity_type_name = dr[8].ToString();
                info.check_results = dr[9].ToString();
                info.remark = dr[10].ToString();
                info.creation_date = FrameWork.ToDateTimeWithNull(dr[11].ToString());
                info.created_by = dr[12].ToString();
                info.last_updated_date = FrameWork.ToDateTimeWithNull(dr[13].ToString());
                info.last_updated_by = dr[14].ToString();
                info.am_head_id = dr[15].ToString();
                info.check = dr[16].ToString();
                info.Seq = Seq;
                list.Add(info);
                Seq++;
            }

 

如果采用dr["columnName"]取列名的方式，一旦数据字段多了，工作量同样不小

foreach (DataRow dr in dt.Rows)
            {
                DeviceInfo info = new DeviceInfo();
                info.Line_ID = dr["LINE_ID"].ToString();
                info.Resource_ID = dr["RESOURCE_ID"].ToString();
                info.Item_ID = dr["ITEM_ID"].ToString();
                info.Item_Desc = dr["ITEM_DESC"].ToString();
                info.Uom = dr["UOM"].ToString();
                info.Desc = dr["DESCRIPTIONS"].ToString();
                info.Avail_Qty = dr["AVAIL_QTY"].ToString();
                info.Lot_Qty = dr["LOT_QTY"].ToString();
                info.Flag = Convert.ToInt32(dr["FLAG"].ToString());
                info.Plan_Flag = Convert.ToInt32(dr["PLAN_FLAG"].ToString());
                info.Item_Code = dr["ITEM_CODE"].ToString();
                info.Flag_Result = info.Flag == 1 ? true : false;
                info.Plan_Flag_Result = info.Plan_Flag == 1 ? true : false; 
                list.Add(info); 
            }

 

所以才有了通过泛型+反射的这种方式    这种方式有个致命的缺点：对象属性的大小写一定要与DataTable中列名一致，不然无法获取到数据

        /// <summary>
        /// 将Datatable数据转换成实体对象集合
        /// </summary>
        /// <typeparam name="T">对象</typeparam>
        /// <param name="dt">Datatable数据</param>
        /// <returns></returns>
        public List<T> ConvertDataTableToList<T>(DataTable dt) where T : new()
        {
            List<T> list = new List<T>();

            foreach (DataRow row in dt.Rows)
            {
                T obj = new T();

                foreach (DataColumn column in dt.Columns)
                {
                    string columnName = column.ColumnName;
                    PropertyInfo property = typeof(T).GetProperty(columnName, BindingFlags.Public | BindingFlags.Instance);

                    if (property != null && row[columnName] != DBNull.Value)
                    {
                        if (property.PropertyType == typeof(DateTime?))
                        {
                            DateTime? value = null;
                            string dateString = row[columnName].ToString();
                            DateTime parsedDate;

                            if (DateTime.TryParse(dateString, out parsedDate))
                            {
                                value = parsedDate;
                            }
                            property.SetValue(obj, value);
                        }
                        else if (property.PropertyType == typeof(int?))
                        {
                            int? value = null;
                            string dateString = row[columnName].ToString();
                            int parsedDate;

                            if (int.TryParse(dateString, out parsedDate))
                            {
                                value = parsedDate;
                            }
                            property.SetValue(obj, value);
                        }
                        else if (property.PropertyType == typeof(bool?))
                        {
                            bool? value = null;
                            string dateString = row[columnName].ToString();
                            bool parsedDate;

                            if (bool.TryParse(dateString, out parsedDate))
                            {
                                value = parsedDate;
                            }
                            property.SetValue(obj, value);
                        }
                        else
                        {
                            object value = Convert.ChangeType(row[columnName], property.PropertyType);
                            property.SetValue(obj, value);
                        }
                    }
                }

                list.Add(obj);
            }

            return list;
        }

 

下面是改良版本，这个版本可以直接用，不用担心对象属性大小写与DataTable列名不一致问题

        public static List<T> ConvertDataTableToList<T>(DataTable dataTable) where T : new()
        {
            List<T> result = new List<T>();

            if (dataTable == null || dataTable.Rows.Count == 0)
            {
                return result;
            }

            foreach (DataRow row in dataTable.Rows)
            {
                T item = CreateItemFromRow<T>(row);
                result.Add(item);
            }

            return result;
        }

        private static T CreateItemFromRow<T>(DataRow row) where T : new()
        {
            T item = new T();
            PropertyInfo[] properties = typeof(T).GetProperties();

            foreach (PropertyInfo property in properties)
            {
                string columnName = property.Name;

                if (!row.Table.Columns.Contains(columnName))
                {
                    foreach (DataColumn column in row.Table.Columns)
                    {
                        if (string.Equals(column.ColumnName, columnName, StringComparison.OrdinalIgnoreCase))
                        {
                            columnName = column.ColumnName;
                            break;
                        }
                    }
                }

                if (row.Table.Columns.Contains(columnName))
                {
                    if (property.PropertyType == typeof(DateTime?))
                    {
                        DateTime? value = null;
                        string dateString = row[columnName].ToString();
                        DateTime parsedDate;

                        if (DateTime.TryParse(dateString, out parsedDate))
                        {
                            value = parsedDate;
                        }
                        property.SetValue(item, value);
                    }
                    else if (property.PropertyType == typeof(int?))
                    {
                        int? value = null;
                        string dateString = row[columnName].ToString();
                        int parsedDate;

                        if (int.TryParse(dateString, out parsedDate))
                        {
                            value = parsedDate;
                        }
                        property.SetValue(item, value);
                    }
                    else if (property.PropertyType == typeof(bool?))
                    {
                        bool? value = null;
                        string dateString = row[columnName].ToString();
                        bool parsedDate;

                        if (bool.TryParse(dateString, out parsedDate))
                        {
                            value = parsedDate;
                        }
                        property.SetValue(item, value);
                    }
                    else
                    {
                        object value = Convert.ChangeType(row[columnName], property.PropertyType);
                        property.SetValue(item, value);
                    }
                }
            }

            return item;
        }