C# Table转换List 或List转换Table

  1 public static class TableListHelper
  2     {
  3
  4         /// <summary>
  5         /// 转化一个DataTable
  6         /// </summary>
  7         /// <typeparam name="T"></typeparam>
  8         /// <param name="list"></param>
  9         /// <returns></returns>
 10         public static DataTable ToDataTable<T>(this IEnumerable<T> list)
 11         {
 12             //创建属性的集合
 13             List<PropertyInfo> pList = new List<PropertyInfo>();
 14             //获得反射的入口
 15             Type type = typeof(T);
 16             DataTable dt = new DataTable();
 17             //把所有的public属性加入到集合 并添加DataTable的列
 18             Array.ForEach<PropertyInfo>(type.GetProperties(), p => { pList.Add(p); dt.Columns.Add(p.Name, p.PropertyType); });
 19             foreach (var item in list)
 20             {
 21                 //创建一个DataRow实例
 22                 DataRow row = dt.NewRow();
 23                 //给row 赋值
 24                 pList.ForEach(p => row[p.Name] = p.GetValue(item, null));
 25                 //加入到DataTable
 26                 dt.Rows.Add(row);
 27             }
 28             return dt;
 29         }
 30
 31
 32         /// <summary>
 33         /// DataTable 转换为List 集合
 34         /// </summary>
 35         /// <typeparam name="TResult">类型</typeparam>
 36         /// <param name="dt">DataTable</param>
 37         /// <returns></returns>
 38         public static List<T> ToList<T>(this DataTable dt) where T : class, new()
 39         {
 40             //创建一个属性的列表
 41             List<PropertyInfo> prlist = new List<PropertyInfo>();
 42             //获取TResult的类型实例  反射的入口
 43
 44             Type t = typeof(T);
 45
 46             //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
 47             Array.ForEach<PropertyInfo>(t.GetProperties(), p => { if (dt.Columns.IndexOf(p.Name) != -1) prlist.Add(p); });
 48
 49             //创建返回的集合
 50
 51             List<T> oblist = new List<T>();
 52
 53             foreach (DataRow row in dt.Rows)
 54             {
 55                 //创建TResult的实例
 56                 T ob = new T();
 57                 //找到对应的数据  并赋值
 58                 prlist.ForEach(p => { if (row[p.Name] != DBNull.Value) p.SetValue(ob, row[p.Name], null); });
 59                 //放入到返回的集合中.
 60                 oblist.Add(ob);
 61             }
 62             return oblist;
 63         }
 64
 65
 66         /// <summary>
 67         /// 将集合类转换成DataTable
 68         /// </summary>
 69         /// <param name="list">集合</param>
 70         /// <returns></returns>
 71         public static DataTable ToDataTableTow(IList list)
 72         {
 73             DataTable result = new DataTable();
 74             if (list.Count > 0)
 75             {
 76                 PropertyInfo[] propertys = list[0].GetType().GetProperties();
 77
 78                 foreach (PropertyInfo pi in propertys)
 79                 {
 80                     result.Columns.Add(pi.Name, pi.PropertyType);
 81                 }
 82                 for (int i = 0; i < list.Count; i++)
 83                 {
 84                     ArrayList tempList = new ArrayList();
 85                     foreach (PropertyInfo pi in propertys)
 86                     {
 87                         object obj = pi.GetValue(list[i], null);
 88                         tempList.Add(obj);
 89                     }
 90                     object[] array = tempList.ToArray();
 91                     result.LoadDataRow(array, true);
 92                 }
 93             }
 94             return result;
 95         }
 96
 97
 98         /// <summary>
 99         /// 将泛型集合类转换成DataTable
100         /// </summary>
101         /// <typeparam name="T">集合项类型</typeparam>
102         /// <param name="list">集合</param>
103         /// <param name="propertyName">需要返回的列的列名</param>
104         /// <returns>数据集(表)</returns>
105         public static DataTable ToDataTable<T>(IList<T> list, params string[] propertyName)
106         {
107             List<string> propertyNameList = new List<string>();
108             if (propertyName != null)
109                 propertyNameList.AddRange(propertyName);
110             DataTable result = new DataTable();
111             if (list.Count > 0)
112             {
113                 PropertyInfo[] propertys = list[0].GetType().GetProperties();
114                 foreach (PropertyInfo pi in propertys)
115                 {
116                     if (propertyNameList.Count == 0)
117                     {
118                         result.Columns.Add(pi.Name, pi.PropertyType);
119                     }
120                     else
121                     {
122                         if (propertyNameList.Contains(pi.Name))
123                             result.Columns.Add(pi.Name, pi.PropertyType);
124                     }
125                 }
126
127                 for (int i = 0; i < list.Count; i++)
128                 {
129                     ArrayList tempList = new ArrayList();
130                     foreach (PropertyInfo pi in propertys)
131                     {
132                         if (propertyNameList.Count == 0)
133                         {
134                             object obj = pi.GetValue(list[i], null);
135                             tempList.Add(obj);
136                         }
137                         else
138                         {
139                             if (propertyNameList.Contains(pi.Name))
140                             {
141                                 object obj = pi.GetValue(list[i], null);
142                                 tempList.Add(obj);
143                             }
144                         }
145                     }
146                     object[] array = tempList.ToArray();
147                     result.LoadDataRow(array, true);
148                 }
149             }
150             return result;
151         }
152
153     }