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  • 利用反射把查询到的Table、Reader转换成List、Model

    菜鸟一枚,入园已有两年三个月,这还是第一次写博客,请各位大神斧正。

    这是我写的一个工具类,通常我们从数据库查询到一个  DataReader  或者是  一个 Table , 想要转换成 一个 list 或者是 一个model 的话 , 一般情况下是使用foreach 循环reader或是tablerows,然后在循环内创建个对象,通过reader[“列名”]来赋值对象的属性。如果表的字段少的话,用这种方式还可以,速度也快一点。但是如果后续还会增加字段的话,那就非常麻烦了,要改很多地方。这工作量太大了,而且还很容易出错。所以这个时候使用反射来转换的话就非常便捷了。我们只管增加字段,改一下数据表对应的model,调用这个工具类的方法,传入相对应的参数就能得到想要的结果。

    诶,文笔不好,直接上代码吧。

      1 public class DynamicGeneric
      2     {
      3         /// <summary>
      4         /// table转list
      5         /// </summary>
      6         /// <typeparam name="T">list类型</typeparam>
      7         /// <param name="obj">model对象</param>
      8         /// <param name="table">数据源table</param>
      9         /// <returns>list</returns>
     10         public static List<T> FillListByDataTable<T>(T obj, DataTable table)
     11         {
     12 
     13             Type type = obj.GetType();
     14 
     15             List<T> list = new List<T>();
     16 
     17             PropertyInfo[] properties = type.GetProperties();//model对象的属性集合
     18 
     19             DataColumnCollection dcc = table.Columns;//列集合
     20 
     21             foreach (DataRow row in table.Rows)
     22             {
     23                 //复制一个model对象
     24                 MemoryStream stream = new MemoryStream();
     25                 BinaryFormatter formatter = new BinaryFormatter();
     26                 formatter.Serialize(stream, obj);
     27                 stream.Position = 0;
     28                 T newObj = (T)formatter.Deserialize(stream);
     29 
     30                 foreach (PropertyInfo pro in properties)
     31                 {
     32                     Type tp = pro.PropertyType;
     33 
     34                     if (dcc.Contains(pro.Name.ToString()))
     35                     {
     36                         if (!string.IsNullOrEmpty(row[pro.Name].ToString()))
     37                         {
     38                             //判断字段类型
     39                             if (tp.Name != "Nullable`1")
     40                             {
     41                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], tp, null));
     42                             }
     43                             if (tp.Name != "Nullable`1")
     44                             {
     45                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], tp));
     46                             }
     47                             else if (tp.FullName.IndexOf("System.DateTime") > 0)
     48                             {
     49                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(DateTime), null));
     50                             }
     51                             else if (tp.FullName.IndexOf("System.Int32") > 0)
     52                             {
     53                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Int32), null));
     54                             }
     55                             else if (tp.FullName.IndexOf("System.Int64") > 0)
     56                             {
     57                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Int64), null));
     58                             }
     59                             else if (tp.FullName.IndexOf("System.Decimal") > 0)
     60                             {
     61                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Decimal), null));
     62                             }
     63                             else if (tp.FullName.IndexOf("System.Boolean") > 0)
     64                             {
     65                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Boolean), null));
     66                             }
     67                         }
     68 
     69                     }
     70                 }
     71                 list.Add(newObj);
     72             }
     73             return list;
     74         }
     75 
     76         /// <summary>
     77         /// reader转list
     78         /// </summary>
     79         /// <typeparam name="T">list类型</typeparam>
     80         /// <param name="obj">model对象</param>
     81         /// <param name="reader">数据源reader</param>
     82         /// <returns>list </returns>
     83         public static List<T> FillListByDataReader<T>(T obj ,IDataReader reader)
     84         {
     85             List<T> list = new List<T>();
     86 
     87             Type t = obj.GetType();
     88 
     89             PropertyInfo[] proList = t.GetProperties();
     90 
     91             while(reader.Read())
     92             {
     93                 MemoryStream stream = new MemoryStream();
     94                 BinaryFormatter formatter = new BinaryFormatter();
     95                 formatter.Serialize(stream, obj);
     96                 stream.Position = 0;
     97                 T newObj = (T)formatter.Deserialize(stream);
     98 
     99                 foreach (PropertyInfo pro in proList)
    100                 {
    101                     Type tp = pro.PropertyType;
    102 
    103                     DataFieldAttribute attr = pro.GetCustomAttributes().Count() > 0 ? pro.GetCustomAttributes().First() as DataFieldAttribute : null;
    104 
    105                     if (attr != null && attr.ColumnName == pro.Name)
    106                     {
    107                         if (ReaderExists(reader, pro.Name) && !string.IsNullOrEmpty(reader[pro.Name].ToString()))
    108                         {
    109                             if (tp.Name != "Nullable`1")
    110                             {
    111                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], tp));
    112                             }
    113                             else if (tp.FullName.IndexOf("System.DateTime") > 0)
    114                             {
    115                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(DateTime), null));
    116                             }
    117                             else if (tp.FullName.IndexOf("System.Int32") > 0)
    118                             {
    119                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Int32), null));
    120                             }
    121                             else if (tp.FullName.IndexOf("System.Int64") > 0)
    122                             {
    123                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Int64), null));
    124                             }
    125                             else if (tp.FullName.IndexOf("System.Decimal") > 0)
    126                             {
    127                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Decimal), null));
    128                             }
    129                             else if (tp.FullName.IndexOf("System.Boolean") > 0)
    130                             {
    131                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Boolean), null));
    132                             }
    133                         }
    134                     }
    135                 }
    136                 list.Add(newObj);
    137             }
    138 
    139             return list;
    140         }
    141 
    142         /// <summary>
    143         /// reader转model对象
    144         /// </summary>
    145         /// <typeparam name="T">类型</typeparam>
    146         /// <param name="obj">model对象</param>
    147         /// <param name="reader">数据源reader</param>
    148         /// <returns>model对象</returns>
    149         public static T FillObjectByDataReader<T>(T obj, IDataReader reader)
    150         {
    151             Type t = obj.GetType();
    152 
    153             PropertyInfo[] proList = t.GetProperties();
    154 
    155             if (reader.Read())
    156             {
    157                 foreach (PropertyInfo pro in proList)
    158                 {
    159                     Type tp = pro.PropertyType;
    160 
    161                     DataFieldAttribute attr = pro.GetCustomAttributes().Count() > 0 ? pro.GetCustomAttributes().First() as DataFieldAttribute : null;
    162 
    163                     if (attr != null && attr.ColumnName == pro.Name)
    164                     {
    165                         if (ReaderExists(reader, pro.Name) && !string.IsNullOrEmpty(reader[pro.Name].ToString()))
    166                         {
    167                             if (tp.Name != "Nullable`1")
    168                             {
    169                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], tp));
    170                             }
    171                             else if (tp.FullName.IndexOf("System.DateTime") > 0)
    172                             {
    173                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(DateTime), null));
    174                             }
    175                             else if (tp.FullName.IndexOf("System.Int32") > 0)
    176                             {
    177                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Int32), null));
    178                             }
    179                             else if (tp.FullName.IndexOf("System.Int64") > 0)
    180                             {
    181                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Int64), null));
    182                             }
    183                             else if (tp.FullName.IndexOf("System.Decimal") > 0)
    184                             {
    185                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Decimal), null));
    186                             }
    187                             else if (tp.FullName.IndexOf("System.Boolean") > 0)
    188                             {
    189                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Boolean), null));
    190                             }
    191                         }
    192                     }
    193                 }
    194             }
    195 
    196             return obj;
    197         }
    198 
    199         /// <summary>
    200         /// row转model对象
    201         /// </summary>
    202         /// <typeparam name="T">model类型</typeparam>
    203         /// <param name="obj">model对象</param>
    204         /// <param name="row">数据源row</param>
    205         /// <returns>model对象</returns>
    206         public static T FillObjectByDataTable<T>(T obj, DataRow row)
    207         {
    208             Type t = obj.GetType();
    209 
    210             PropertyInfo[] proList = t.GetProperties();
    211 
    212             foreach (PropertyInfo pro in proList)
    213             {
    214                 Type tp = pro.PropertyType;
    215 
    216                 DataFieldAttribute attr = pro.GetCustomAttributes().Count() > 0 ? pro.GetCustomAttributes().First() as DataFieldAttribute : null;
    217 
    218                 if (attr != null && attr.ColumnName == pro.Name)
    219                 {
    220                     if (!string.IsNullOrEmpty(row[pro.Name].ToString()))
    221                     {
    222                         if (tp.Name != "Nullable`1")
    223                         {
    224                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], tp, null));
    225                         }
    226                         if (tp.Name != "Nullable`1")
    227                         {
    228                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], tp));
    229                         }
    230                         else if (tp.FullName.IndexOf("System.DateTime") > 0)
    231                         {
    232                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(DateTime), null));
    233                         }
    234                         else if (tp.FullName.IndexOf("System.Int32") > 0)
    235                         {
    236                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Int32), null));
    237                         }
    238                         else if (tp.FullName.IndexOf("System.Int64") > 0)
    239                         {
    240                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Int64), null));
    241                         }
    242                         else if (tp.FullName.IndexOf("System.Decimal") > 0)
    243                         {
    244                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Decimal), null));
    245                         }
    246                         else if (tp.FullName.IndexOf("System.Boolean") > 0)
    247                         {
    248                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Boolean), null));
    249                         }
    250                     }
    251 
    252                 }
    253             }
    254 
    255 
    256             return obj;
    257         }
    258 
    259         /// <summary>
    260         /// list转table
    261         /// </summary>
    262         /// <typeparam name="T">list类型</typeparam>
    263         /// <param name="list">数据源list</param>
    264         /// <param name="table">table</param>
    265         /// <returns>table</returns>
    266         public static DataTable FillDataTableByObject<T>(List<T> list , DataTable table)
    267         {
    268             if (list.Count > 0)
    269             {
    270                 Type type = list[0].GetType();
    271 
    272                 PropertyInfo[] properties = type.GetProperties();
    273 
    274                 DataColumnCollection dcc = table.Columns;
    275 
    276                 foreach (var obj in list)
    277                 {
    278                     DataRow row = table.NewRow();
    279                     foreach (PropertyInfo p in properties)
    280                     {
    281                         if (dcc.Contains(p.Name.ToString()))
    282                         {
    283                             row[p.Name] = p.GetValue(obj);
    284                         }
    285                     }
    286                     table.Rows.Add(row);
    287                 }
    288             }
    289             return table;
    290         }
    291 
    292         /// <summary>
    293         /// 验证reader是否存在某列
    294         /// </summary>
    295         /// <param name="reader"></param>
    296         /// <param name="columnName"></param>
    297         /// <returns></returns>
    298         private static bool ReaderExists(IDataReader reader,string columnName)
    299         {
    300             int count = reader.FieldCount;
    301             for(int i = 0; i < count; i++)
    302             {
    303                 if(reader.GetName(i).Equals(columnName))
    304                 {
    305                     return true;
    306                 }
    307             }
    308             return false;
    309         }
    310 
    311         
    312     }
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  • 原文地址:https://www.cnblogs.com/lifuquan/p/5466043.html
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