datatable 转list ,list转datatable

方法一：

 public static IList<T> ConvertToModel(DataTable dt)   

         {   

            // 定义集合   

             IList<T> ts = new List<T>();

     

            // 获得此模型的类型  

             Type type = typeof(T);     

            string tempName = "";     

      

            foreach (DataRow dr in dt.Rows)     

             {   

                 T t = new T();    

                // 获得此模型的公共属性     

                 PropertyInfo[] propertys = t.GetType().GetProperties();

                foreach (PropertyInfo pi in propertys)     

                 {     

                     tempName = pi.Name;  // 检查DataTable是否包含此列   

   

                    if (dt.Columns.Contains(tempName))     

                     {     

                        // 判断此属性是否有Setter     

                        if (!pi.CanWrite) continue;        

   

                        object value = dr[tempName];     

                        if (value != DBNull.Value)     

                             pi.SetValue(t, value, null); 

                     }    

                 }     

                 ts.Add(t);     

             }    

            return ts;    

         }    

     }   

方法二：

var query = from t in dt.AsEnumerable().ToList()
group t by new { t1 = t.Field<string>("CustomerID") } into m
select new
{
name = m.Key.t1,
score = m.Sum(n => n.Field<Int32>("aa")),
ss = m.Sum(n => n.Field<Int32>("vv"))
};

list转table：

方法一：

 DataTable dt22= ToDataTable(query.Where(p=>1==1));

public static DataTable ToDataTable<T>(IEnumerable<T> collection)
{
var props = typeof(T).GetProperties();
var dt = new DataTable();
dt.Columns.AddRange(props.Select(p => new DataColumn(p.Name, p.PropertyType)).ToArray());
if (collection.Count() > 0)
{
for (int i = 0; i < collection.Count(); i++)
{
ArrayList tempList = new ArrayList();
foreach (PropertyInfo pi in props)
{
object obj = pi.GetValue(collection.ElementAt(i), null);
tempList.Add(obj);
}
object[] array = tempList.ToArray();
dt.LoadDataRow(array, true);
}
}
return dt;
}