datatable与实体相互转换 反射

namespace Mall.Config
{
/// <summary>
    /// DataTable与实体类互相转换
    /// </summary>
    /// <typeparam name="T">实体类</typeparam>
    public class ModelHandler<T> where T : new()
    {
        #region DataTable转换成实体类

        /// <summary>
        /// 填充对象列表：用DataSet的第一个表填充实体类
        /// </summary>
        /// <param name="ds">DataSet</param>
        /// <returns></returns>
        public List<T> FillModel(DataSet ds)
        {
            if (ds == null || ds.Tables[0] == null || ds.Tables[0].Rows.Count == 0)
            {
                return null;
            }
            else
            {
                return FillModel(ds.Tables[0]);
            }
        }

        /// <summary>  
        /// 填充对象列表：用DataSet的第index个表填充实体类
        /// </summary>  
        public List<T> FillModel(DataSet ds, int index)
        {
            if (ds == null || ds.Tables.Count <= index || ds.Tables[index].Rows.Count == 0)
            {
                return null;
            }
            else
            {
                return FillModel(ds.Tables[index]);
            }
        }

        /// <summary>  
        /// 填充对象列表：用DataTable填充实体类
        /// </summary>  
        public List<T> FillModel(DataTable dt)
        {
            if (dt == null || dt.Rows.Count == 0)
            {
                return null;
            }
            List<T> modelList = new List<T>();
            foreach (DataRow dr in dt.Rows)
            {
                //T model = (T)Activator.CreateInstance(typeof(T));  
                T model = new T();
                for (int i = 0; i < dr.Table.Columns.Count; i++)
                {
                    PropertyInfo propertyInfo = model.GetType().GetProperty(dr.Table.Columns[i].ColumnName);
                    if (propertyInfo != null && dr[i] != DBNull.Value)
                        propertyInfo.SetValue(model, dr[i], null);
                }

                modelList.Add(model);
            }
            return modelList;
        }

        /// <summary>  
        /// 填充对象：用DataRow填充实体类
        /// </summary>  
        public T FillModel(DataRow dr)
        {
            if (dr == null)
            {
                return default(T);
            }

            //T model = (T)Activator.CreateInstance(typeof(T));  
            T model = new T();

            for (int i = 0; i < dr.Table.Columns.Count; i++)
            {
                PropertyInfo propertyInfo = model.GetType().GetProperty(dr.Table.Columns[i].ColumnName);
                if (propertyInfo != null && dr[i] != DBNull.Value)
                    propertyInfo.SetValue(model, dr[i], null);
            }
            return model;
        }

        #endregion

        #region 实体类转换成DataTable

        /// <summary>
        /// 实体类转换成DataSet
        /// </summary>
        /// <param name="modelList">实体类列表</param>
        /// <returns></returns>
        public DataSet FillDataSet(List<T> modelList)
        {
            if (modelList == null || modelList.Count == 0)
            {
                return null;
            }
            else
            {
                DataSet ds = new DataSet();
                ds.Tables.Add(FillDataTable(modelList));
                return ds;
            }
        }

        /// <summary>
        /// 实体类转换成DataTable
        /// </summary>
        /// <param name="modelList">实体类列表</param>
        /// <returns></returns>
        public DataTable FillDataTable(List<T> modelList)
        {
            if (modelList == null || modelList.Count == 0)
            {
                return null;
            }
            DataTable dt = CreateData(modelList[0]);

            foreach (T model in modelList)
            {
                DataRow dataRow = dt.NewRow();
                foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                {
                    dataRow[propertyInfo.Name] = propertyInfo.GetValue(model, null);
                }
                dt.Rows.Add(dataRow);
            }
            return dt;
        }

        /// <summary>
        /// 根据实体类得到表结构
        /// </summary>
        /// <param name="model">实体类</param>
        /// <returns></returns>
        private DataTable CreateData(T model)
        {
            DataTable dataTable = new DataTable(typeof(T).Name);
            foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
            {
                dataTable.Columns.Add(new DataColumn(propertyInfo.Name, propertyInfo.PropertyType));
            }
            return dataTable;
        }


        /// <summary>
        /// 实体类转换成DataTable
        /// </summary>
        /// <param name="modelList">实体类列表</param>
        /// <param name="nameList">具体列集合</param>
        /// <returns></returns>
        public DataTable FillDataTable(List<T> modelList, List<string> nameList)
        {
            if (modelList == null || modelList.Count == 0)
            {
                return null;
            }
            DataTable dt = CreateData(modelList[0], nameList);

            foreach (T model in modelList)
            {
                DataRow dataRow = dt.NewRow();
                foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                {
                    foreach (string item in nameList)
                    {
                        string[] arr = item.Split(‘,‘);
                        if (arr[0] == propertyInfo.Name)
                        {
                            string temp = "";
                            switch (arr[2])
                            {
                                case "Int":
                                    temp = propertyInfo.GetValue(model, null).ToString() == "无数据"
                                        ? propertyInfo.GetValue(model, null).ToString()
                                        : Math.Round((double)propertyInfo.GetValue(model, null), 0).ToString();
                                    break;
                                case "Double":
                                    if (propertyInfo.GetValue(model, null).ToString() == "--")
                                        temp = "--";
                                    else if (propertyInfo.GetValue(model, null).ToString() == "无数据")
                                        temp = "无数据";
                                    else if (propertyInfo.GetValue(model, null).ToString().Contains("%"))
                                        temp = propertyInfo.GetValue(model, null).ToString();
                                    else
                                        temp = Math.Round((double)propertyInfo.GetValue(model, null), 2).ToString();
                                    break;
                                default:
                                    if (propertyInfo.GetValue(model, null) != null)
                                    {
                                        temp = propertyInfo.GetValue(model, null).ToString();
                                    }
                                    break;
                            }
                            dataRow[arr[1]] = temp;
                        }
                    }


                    //if (nameList.Contains(propertyInfo.Name))
                    //{
                    //    string temp = "";
                    //    temp = (propertyInfo.PropertyType).FullName == "System.Double"
                    //        ? Math.Round((double)propertyInfo.GetValue(model, null), 2).ToString()
                    //        : propertyInfo.GetValue(model, null).ToString();

                    //    dataRow[propertyInfo.Name] = temp;
                    //}
                }
                dt.Rows.Add(dataRow);
            }
            return dt;
        }


        /// <summary>
        /// 根据实体类得到表结构
        /// </summary>
        /// <param name="model">实体类</param>
        /// <param name="nameList"></param>
        /// <returns></returns>
        private DataTable CreateData(T model, List<string> nameList)
        {
            DataTable dataTable = new DataTable(typeof(T).Name);
            foreach (string name in nameList)
            {
                string[] arr = name.Split(‘,‘);
                foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                {
                    if (arr[0] == propertyInfo.Name)
                    {
                        //dataTable.Columns.Add(new DataColumn(propertyInfo.Name, propertyInfo.PropertyType));
                        dataTable.Columns.Add(new DataColumn(arr[1], propertyInfo.PropertyType));
                    }
                }
            }
            return dataTable;
        }
        #endregion
    }

}





调用：Mall.Config.ModelHandler<Bus_OnLine_Custom_Info> handler = new ModelHandler<Bus_OnLine_Custom_Info>();
DataTable dt = handler.FillDataTable(online.busonline_list, list);