List To IDatareader For SqlBulkCopy

原文地址：http://www.csvreader.com/csv_downloads.php 或 

　　　　　http://technico.qnownow.com/custom-data-reader-to-bulk-copy-data-from-object-collection-to-sql-server/

使用场景：

　　项目中通过业务逻辑生产了多个大List<T>对象，需要使用bcp方式保存到数据库，有两种方式：

1.把List<T>转成DataTable，然后保存。确定就是内存占用很多。

 2.实现一个IDataReader对象，解决内存增长问题。

通用的转换代码如下：

  1 public class GenericListDataReader<T> : IDataReader
  2     {
  3         private IEnumerator<T> list = null;
  4         private List<PropertyInfo> properties = new List<PropertyInfo>();
  5 
  6         public GenericListDataReader(IEnumerable<T> list)
  7         {
  8             this.list = list.GetEnumerator();
  9             foreach (PropertyInfo property in typeof(T).GetProperties(
 10                 BindingFlags.GetProperty |
 11                 BindingFlags.Instance |
 12                 BindingFlags.Public))
 13             {
 14                 if (
 15                     property.PropertyType.IsPrimitive ||
 16                     property.PropertyType == typeof(string) ||
 17                     property.PropertyType == typeof(DateTime)
 18                     )
 19                 {
 20                     properties.Add(property);
 21                 }
 22             }
 23         }
 24 
 25         #region IDataReader Members
 26 
 27         public void Close()
 28         {
 29             list.Dispose();
 30         }
 31 
 32         public int Depth
 33         {
 34             get { throw new NotImplementedException(); }
 35         }
 36 
 37         public DataTable GetSchemaTable()
 38         {
 39             throw new NotImplementedException();
 40         }
 41 
 42         public bool IsClosed
 43         {
 44             get { throw new NotImplementedException(); }
 45         }
 46 
 47         public bool NextResult()
 48         {
 49             throw new NotImplementedException();
 50         }
 51 
 52         public bool Read()
 53         {
 54             return list.MoveNext();
 55         }
 56 
 57         public int RecordsAffected
 58         {
 59             get { throw new NotImplementedException(); }
 60         }
 61 
 62         #endregion
 63 
 64         #region IDisposable Members
 65 
 66         public void Dispose()
 67         {
 68             Close();
 69         }
 70 
 71         #endregion
 72 
 73         #region IDataRecord Members
 74 
 75         public int FieldCount
 76         {
 77             get { return properties.Count; }
 78         }
 79 
 80         public bool GetBoolean(int i)
 81         {
 82             throw new NotImplementedException();
 83         }
 84 
 85         public byte GetByte(int i)
 86         {
 87             throw new NotImplementedException();
 88         }
 89 
 90         public long GetBytes(int i, long fieldOffset, byte[] buffer, int bufferoffset, int length)
 91         {
 92             throw new NotImplementedException();
 93         }
 94 
 95         public char GetChar(int i)
 96         {
 97             throw new NotImplementedException();
 98         }
 99 
100         public long GetChars(int i, long fieldoffset, char[] buffer, int bufferoffset, int length)
101         {
102             throw new NotImplementedException();
103         }
104 
105         public IDataReader GetData(int i)
106         {
107             throw new NotImplementedException();
108         }
109 
110         public string GetDataTypeName(int i)
111         {
112             throw new NotImplementedException();
113         }
114 
115         public DateTime GetDateTime(int i)
116         {
117             throw new NotImplementedException();
118         }
119 
120         public decimal GetDecimal(int i)
121         {
122             throw new NotImplementedException();
123         }
124 
125         public double GetDouble(int i)
126         {
127             throw new NotImplementedException();
128         }
129 
130         public Type GetFieldType(int i)
131         {
132             return properties[i].PropertyType;
133         }
134 
135         public float GetFloat(int i)
136         {
137             throw new NotImplementedException();
138         }
139 
140         public Guid GetGuid(int i)
141         {
142             throw new NotImplementedException();
143         }
144 
145         public short GetInt16(int i)
146         {
147             throw new NotImplementedException();
148         }
149 
150         public int GetInt32(int i)
151         {
152             throw new NotImplementedException();
153         }
154 
155         public long GetInt64(int i)
156         {
157             throw new NotImplementedException();
158         }
159 
160         public string GetName(int i)
161         {
162             return properties[i].Name;
163         }
164 
165         public int GetOrdinal(string name)
166         {
167             throw new NotImplementedException();
168         }
169 
170         public string GetString(int i)
171         {
172             throw new NotImplementedException();
173         }
174 
175         public object GetValue(int i)
176         {
177             return properties[i].GetValue(list.Current, null);
178         }
179 
180         public int GetValues(object[] values)
181         {
182             throw new NotImplementedException();
183         }
184 
185         public bool IsDBNull(int i)
186         {
187             throw new NotImplementedException();
188         }
189 
190         public object this[string name]
191         {
192             get { throw new NotImplementedException(); }
193         }
194 
195         public object this[int i]
196         {
197             get { throw new NotImplementedException(); }
198         }
199 
200         #endregion
201     }

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