List<T>转换为DataTable

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;

       }

   }