【.Net码农】【PropertyInfo】List<T>转换为DataTable

来源：互联网发布：微信时时彩源码编辑：程序博客网时间：2024/04/25 22:25

http://blog.csdn.net/emoonight/article/details/6617683

今天小姚碰到个问题,有个以前的程序直接调用数据库用dataset和datatable.但是现在想加一层Model层.获取List<T>后赋值给Table时碰到难题.

本来我觉得这就是个简单的问题,将Table看做一张表,直接循环List后赋值即可.查了下资料才知道自己把DataTable想得太简单了....

先说后来用到的方法一

List<info> infos = Dal.GetInfos();        DataTable dt = new DataTable();        dt.Columns.Add("cName");        foreach (var info in infos)        {            DataRow dr = dt.NewRow();            dr["cName"] = info.Name;            dt.Add(dr);        }

网上的:

public static class DataTableExtensions{    /// <summary>      /// 转化一个DataTable      /// </summary>      /// <typeparam name="T"></typeparam>      /// <param name="list"></param>      /// <returns></returns>      public static DataTable ToDataTable<T>(this IEnumerable<T> list)    {        //创建属性的集合          List<PropertyInfo> pList = new List<PropertyInfo>();        //获得反射的入口          Type type = typeof(T);        DataTable dt = new DataTable();        //把所有的public属性加入到集合 并添加DataTable的列          Array.ForEach<PropertyInfo>(type.GetProperties(), p => { pList.Add(p); dt.Columns.Add(p.Name, p.PropertyType); });        foreach (var item in list)        {            //创建一个DataRow实例              DataRow row = dt.NewRow();            //给row 赋值              pList.ForEach(p => row[p.Name] = p.GetValue(item, null));            //加入到DataTable              dt.Rows.Add(row);        }        return dt;    }    /// <summary>      /// DataTable 转换为List 集合      /// </summary>      /// <typeparam name="TResult">类型</typeparam>      /// <param name="dt">DataTable</param>      /// <returns></returns>      public static List<T> ToList<T>(this DataTable dt) where T : class, new()    {        //创建一个属性的列表          List<PropertyInfo> prlist = new List<PropertyInfo>();        //获取TResult的类型实例  反射的入口          Type t = typeof(T);        //获得TResult 的所有的Public 属性 并找出TResult属性和DataTable的列名称相同的属性(PropertyInfo) 并加入到属性列表           Array.ForEach<PropertyInfo>(t.GetProperties(), p => { if (dt.Columns.IndexOf(p.Name) != -1) prlist.Add(p); });        //创建返回的集合          List<T> oblist = new List<T>();        foreach (DataRow row in dt.Rows)        {            //创建TResult的实例              T ob = new T();            //找到对应的数据  并赋值              prlist.ForEach(p => { if (row[p.Name] != DBNull.Value) p.SetValue(ob, row[p.Name], null); });            //放入到返回的集合中.              oblist.Add(ob);        }        return oblist;    }    /// <summary>      /// 将集合类转换成DataTable      /// </summary>      /// <param name="list">集合</param>      /// <returns></returns>      public static DataTable ToDataTableTow(IList list)    {        DataTable result = new DataTable();        if (list.Count > 0)        {            PropertyInfo[] propertys = list[0].GetType().GetProperties();            foreach (PropertyInfo pi in propertys)            {                result.Columns.Add(pi.Name, pi.PropertyType);            }            for (int i = 0; i < list.Count; i++)            {                ArrayList tempList = new ArrayList();                foreach (PropertyInfo pi in propertys)                {                    object obj = pi.GetValue(list[i], null);                    tempList.Add(obj);                }                object[] array = tempList.ToArray();                result.LoadDataRow(array, true);            }        }        return result;    }    /**/    /// <summary>      /// 将泛型集合类转换成DataTable      /// </summary>      /// <typeparam name="T">集合项类型</typeparam>      /// <param name="list">集合</param>      /// <returns>数据集(表)</returns>      public static DataTable ToDataTable<T>(IList<T> list)    {        return ToDataTable<T>(list, null);    }    /**/    /// <summary>      /// 将泛型集合类转换成DataTable      /// </summary>      /// <typeparam name="T">集合项类型</typeparam>      /// <param name="list">集合</param>      /// <param name="propertyName">需要返回的列的列名</param>      /// <returns>数据集(表)</returns>      public static DataTable ToDataTable<T>(IList<T> list, params string[] propertyName)    {        List<string> propertyNameList = new List<string>();        if (propertyName != null)            propertyNameList.AddRange(propertyName);        DataTable result = new DataTable();        if (list.Count > 0)        {            PropertyInfo[] propertys = list[0].GetType().GetProperties();            foreach (PropertyInfo pi in propertys)            {                if (propertyNameList.Count == 0)                {                    result.Columns.Add(pi.Name, pi.PropertyType);                }                else                {                    if (propertyNameList.Contains(pi.Name))                        result.Columns.Add(pi.Name, pi.PropertyType);                }            }            for (int i = 0; i < list.Count; i++)            {                ArrayList tempList = new ArrayList();                foreach (PropertyInfo pi in propertys)                {                    if (propertyNameList.Count == 0)                    {                        object obj = pi.GetValue(list[i], null);                        tempList.Add(obj);                    }                    else                    {                        if (propertyNameList.Contains(pi.Name))                        {                            object obj = pi.GetValue(list[i], null);                            tempList.Add(obj);                        }                    }                }                object[] array = tempList.ToArray();                result.LoadDataRow(array, true);            }        }        return result;    }}

0 0