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table的rows，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。

 public class DynamicGeneric
     {
         /// <summary>
         /// table转list
         /// </summary>
         /// <typeparam name="T">list类型</typeparam>
         /// <param name="obj">model对象</param>
         /// <param name="table">数据源table</param>
         /// <returns>list</returns>
         public static List<T> FillListByDataTable<T>(T obj, DataTable table)
         {

             Type type = obj.GetType();

             List<T> list = new List<T>();

             PropertyInfo[] properties = type.GetProperties();//model对象的属性集合

             DataColumnCollection dcc = table.Columns;//列集合

             foreach (DataRow row in table.Rows)
             {
                 //复制一个model对象
                 MemoryStream stream = new MemoryStream();
                 BinaryFormatter formatter = new BinaryFormatter();
                 formatter.Serialize(stream, obj);
                 stream.Position = ;
                 T newObj = (T)formatter.Deserialize(stream);

                 foreach (PropertyInfo pro in properties)
                 {
                     Type tp = pro.PropertyType;

                     if (dcc.Contains(pro.Name.ToString()))
                     {
                         if (!string.IsNullOrEmpty(row[pro.Name].ToString()))
                         {
                             //判断字段类型
                             if (tp.Name != "Nullable`1")
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], tp, null));
                             }
                             if (tp.Name != "Nullable`1")
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], tp));
                             }
                             else if (tp.FullName.IndexOf("System.DateTime") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(DateTime), null));
                             }
                             else if (tp.FullName.IndexOf("System.Int32") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Int32), null));
                             }
                             else if (tp.FullName.IndexOf("System.Int64") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Int64), null));
                             }
                             else if (tp.FullName.IndexOf("System.Decimal") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Decimal), null));
                             }
                             else if (tp.FullName.IndexOf("System.Boolean") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(row[pro.Name], typeof(Boolean), null));
                             }
                         }

                     }
                 }
                 list.Add(newObj);
             }
             return list;
         }

         /// <summary>
         /// reader转list
         /// </summary>
         /// <typeparam name="T">list类型</typeparam>
         /// <param name="obj">model对象</param>
         /// <param name="reader">数据源reader</param>
         /// <returns>list </returns>
         public static List<T> FillListByDataReader<T>(T obj ,IDataReader reader)
         {
             List<T> list = new List<T>();

             Type t = obj.GetType();

             PropertyInfo[] proList = t.GetProperties();

             while(reader.Read())
             {
                 MemoryStream stream = new MemoryStream();
                 BinaryFormatter formatter = new BinaryFormatter();
                 formatter.Serialize(stream, obj);
                 stream.Position = ;
                 T newObj = (T)formatter.Deserialize(stream);

                 foreach (PropertyInfo pro in proList)
                 {
                     Type tp = pro.PropertyType;

                     DataFieldAttribute attr = pro.GetCustomAttributes().Count() >  ? pro.GetCustomAttributes().First() as DataFieldAttribute : null;

                     if (attr != null && attr.ColumnName == pro.Name)
                     {
                         if (ReaderExists(reader, pro.Name) && !string.IsNullOrEmpty(reader[pro.Name].ToString()))
                         {
                             if (tp.Name != "Nullable`1")
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], tp));
                             }
                             else if (tp.FullName.IndexOf("System.DateTime") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(DateTime), null));
                             }
                             else if (tp.FullName.IndexOf("System.Int32") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Int32), null));
                             }
                             else if (tp.FullName.IndexOf("System.Int64") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Int64), null));
                             }
                             else if (tp.FullName.IndexOf("System.Decimal") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Decimal), null));
                             }
                             else if (tp.FullName.IndexOf("System.Boolean") > )
                             {
                                 pro.SetValue(newObj, Convert.ChangeType(reader[pro.Name], typeof(Boolean), null));
                             }
                         }
                     }
                 }
                 list.Add(newObj);
             }

             return list;
         }

         /// <summary>
         /// reader转model对象
         /// </summary>
         /// <typeparam name="T">类型</typeparam>
         /// <param name="obj">model对象</param>
         /// <param name="reader">数据源reader</param>
         /// <returns>model对象</returns>
         public static T FillObjectByDataReader<T>(T obj, IDataReader reader)
         {
             Type t = obj.GetType();

             PropertyInfo[] proList = t.GetProperties();

             if (reader.Read())
             {
                 foreach (PropertyInfo pro in proList)
                 {
                     Type tp = pro.PropertyType;

                     DataFieldAttribute attr = pro.GetCustomAttributes().Count() >  ? pro.GetCustomAttributes().First() as DataFieldAttribute : null;

                     if (attr != null && attr.ColumnName == pro.Name)
                     {
                         if (ReaderExists(reader, pro.Name) && !string.IsNullOrEmpty(reader[pro.Name].ToString()))
                         {
                             if (tp.Name != "Nullable`1")
                             {
                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], tp));
                             }
                             else if (tp.FullName.IndexOf("System.DateTime") > )
                             {
                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(DateTime), null));
                             }
                             else if (tp.FullName.IndexOf("System.Int32") > )
                             {
                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Int32), null));
                             }
                             else if (tp.FullName.IndexOf("System.Int64") > )
                             {
                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Int64), null));
                             }
                             else if (tp.FullName.IndexOf("System.Decimal") > )
                             {
                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Decimal), null));
                             }
                             else if (tp.FullName.IndexOf("System.Boolean") > )
                             {
                                 pro.SetValue(obj, Convert.ChangeType(reader[pro.Name], typeof(Boolean), null));
                             }
                         }
                     }
                 }
             }

             return obj;
         }

         /// <summary>
         /// row转model对象
         /// </summary>
         /// <typeparam name="T">model类型</typeparam>
         /// <param name="obj">model对象</param>
         /// <param name="row">数据源row</param>
         /// <returns>model对象</returns>
         public static T FillObjectByDataTable<T>(T obj, DataRow row)
         {
             Type t = obj.GetType();

             PropertyInfo[] proList = t.GetProperties();

             foreach (PropertyInfo pro in proList)
             {
                 Type tp = pro.PropertyType;

                 DataFieldAttribute attr = pro.GetCustomAttributes().Count() >  ? pro.GetCustomAttributes().First() as DataFieldAttribute : null;

                 if (attr != null && attr.ColumnName == pro.Name)
                 {
                     if (!string.IsNullOrEmpty(row[pro.Name].ToString()))
                     {
                         if (tp.Name != "Nullable`1")
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], tp, null));
                         }
                         if (tp.Name != "Nullable`1")
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], tp));
                         }
                         else if (tp.FullName.IndexOf("System.DateTime") > )
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(DateTime), null));
                         }
                         else if (tp.FullName.IndexOf("System.Int32") > )
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Int32), null));
                         }
                         else if (tp.FullName.IndexOf("System.Int64") > )
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Int64), null));
                         }
                         else if (tp.FullName.IndexOf("System.Decimal") > )
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Decimal), null));
                         }
                         else if (tp.FullName.IndexOf("System.Boolean") > )
                         {
                             pro.SetValue(obj, Convert.ChangeType(row[pro.Name], typeof(Boolean), null));
                         }
                     }

                 }
             }

             return obj;
         }

         /// <summary>
         /// list转table
         /// </summary>
         /// <typeparam name="T">list类型</typeparam>
         /// <param name="list">数据源list</param>
         /// <param name="table">table</param>
         /// <returns>table</returns>
         public static DataTable FillDataTableByObject<T>(List<T> list , DataTable table)
         {
             if (list.Count > )
             {
                 Type type = list[].GetType();

                 PropertyInfo[] properties = type.GetProperties();

                 DataColumnCollection dcc = table.Columns;

                 foreach (var obj in list)
                 {
                     DataRow row = table.NewRow();
                     foreach (PropertyInfo p in properties)
                     {
                         if (dcc.Contains(p.Name.ToString()))
                         {
                             row[p.Name] = p.GetValue(obj);
                         }
                     }
                     table.Rows.Add(row);
                 }
             }
             return table;
         }

         /// <summary>
         /// 验证reader是否存在某列
         /// </summary>
         /// <param name="reader"></param>
         /// <param name="columnName"></param>
         /// <returns></returns>
         private static bool ReaderExists(IDataReader reader,string columnName)
         {
             int count = reader.FieldCount;
             for(int i = ; i < count; i++)
             {
                 if(reader.GetName(i).Equals(columnName))
                 {
                     return true;
                 }
             }
             return false;
         }

     }