自己寫的訪問SqlServer數據庫的通用DAL層

本文轉載自查看原文 2015-05-19 15:08 909

如題,直接貼代碼.

首先是DataTable轉List<T>的方法,這個方法通用性極強.

 1         #region Table轉List
 2         /// <summary>
 3         /// Table轉List
 4         /// </summary>
 5         /// <typeparam name="T"></typeparam>
 6         /// <param name="dt"></param>
 7         /// <returns></returns>
 8         public static List<T> TableToList<T>(DataTable dt) where T : new()
 9         {
10             // 定義集合
11             IList<T> list = new List<T>();
12 
13             // 獲得此模型的類型
14             Type type = typeof(T);
15 
16             foreach (DataRow dr in dt.Rows)
17             {
18                 T t = new T();
19 
20                 // 獲得公共屬性
21                 PropertyInfo[] propertys = t.GetType().GetProperties();
22 
23                 foreach (PropertyInfo pi in propertys)
24                 {
25                     // 判斷此屬性是否有Setter
26                     if (!pi.CanWrite) continue;
27 
28                     object value = dr[pi.Name];
29                     if (value != DBNull.Value)
30                         pi.SetValue(t, value, null);
31                 }
32 
33                 list.Add(t);
34             }
35             return list.ToList();
36         }
37         #endregion

View Code

下面貼出主要代碼

  1     /// <summary>
  2     /// 數據訪問基類:BaseService
  3     /// </summary>
  4     /// <typeparam name="T"></typeparam>
  5     public class BaseService<T> : IBaseService<T> where T : class ,new()
  6     {
  7         /// <summary>
  8         /// 得到某列最大值
  9         /// </summary>
 10         /// <param name="connection"></param>
 11         /// <param name="fieldname"></param>
 12         /// <returns></returns>
 13         public virtual int GetMax(string connection,string fieldname)
 14         {
 15             #region 參數
 16             T entity = new T();
 17             SqlParameter[] parameters = new SqlParameter[]
 18             {
 19                 new SqlParameter("@fieldname",fieldname)
 20             }; 
 21             #endregion
 22 
 23             StringBuilder sqlStr=new StringBuilder();
 24             sqlStr.Append("select max(");
 25             sqlStr.Append("@fieldname");
 26             sqlStr.Append(") from ");
 27             sqlStr.Append(entity.GetType().Name);
 28 
 29             return int.Parse(DatabaseAccess.SqlHelper.ExecuteDataSetText(connection, sqlStr.ToString(), parameters).Tables[0].Rows[0][0].ToString());
 30         }
 31 
 32         /// <summary>
 33         /// 是否存在該記錄
 34         /// </summary>
 35         /// <param name="connection">連接字符串</param>
 36         /// <param name="primarykey">主鍵值</param>
 37         /// <returns></returns>
 38         public virtual bool Exists(string connection, object primarykey)
 39         {
 40             #region 參數
 41             T entity = new T();
 42 
 43             string primaryKey = GetPrimarykey(connection, entity);
 44             List<SqlParameter> parameters = new List<SqlParameter>();
 45             parameters.Add(new SqlParameter("@" + primaryKey, primarykey));
 46             #endregion
 47 
 48             StringBuilder sqlStr = new StringBuilder();
 49             sqlStr.Append("select count(1) from ");
 50             sqlStr.Append(entity.GetType().Name);
 51             sqlStr.Append(" where ");
 52             sqlStr.Append(primaryKey + "=@" + primaryKey);
 53 
 54             int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray());
 55             if (res > 0)
 56                 return true;
 57             else
 58                 return false;
 59         }
 60 
 61         /// <summary>
 62         /// 增加一條數據
 63         /// </summary>
 64         public virtual bool Add(string connection, T entity)
 65         {
 66             #region 參數
 67             List<SqlParameter> parameters = new List<SqlParameter>();
 68             string fields = "";
 69             string placeholders = "";
 70             foreach (var item in entity.GetType().GetProperties())
 71             {
 72                 fields += item.Name + ",";
 73                 placeholders += "@" + item.Name + ",";
 74 
 75                 SqlParameter parameter = new SqlParameter();
 76                 parameter.ParameterName = "@" + item.Name;
 77                 parameter.Value = item.GetValue(entity, null);
 78                 parameters.Add(parameter);
 79             }
 80             #endregion
 81 
 82             StringBuilder sqlStr = new StringBuilder();
 83             sqlStr.Append("insert " + entity.GetType().Name + " (");
 84             sqlStr.Append(fields.Substring(0, fields.Length - 1) + ")");
 85             sqlStr.Append(" values (");
 86             sqlStr.Append(placeholders.Substring(0, placeholders.Length - 1) + ")");
 87 
 88             int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray());
 89             if (res > 0)
 90                 return true;
 91             else
 92                 return false;
 93         }
 94 
 95         /// <summary>
 96         /// 更新一條數據
 97         /// </summary>
 98         /// <param name="connection">連接字符串</param>
 99         /// <param name="entity">類</param>
100         /// <returns></returns>
101         public virtual bool Update(string connection, T entity)
102         {
103             #region 參數
104             string primaryKey = GetPrimarykey(connection, entity);
105             List<SqlParameter> parameters = new List<SqlParameter>();
106             parameters.Add(new SqlParameter("@"+primaryKey, entity.GetType().GetProperty(primaryKey).GetValue(entity,null)));
107             string fields = "";
108             foreach (var item in entity.GetType().GetProperties())
109             {
110                 if (item.Name != primaryKey)
111                 {
112                     fields += item.Name + "=@" + item.Name + ",";
113 
114                     SqlParameter parameter = new SqlParameter();
115                     parameter.ParameterName = "@" + item.Name;
116                     parameter.Value = item.GetValue(entity, null);
117                     parameters.Add(parameter);
118                 }
119             }
120             #endregion
121 
122             StringBuilder sqlStr = new StringBuilder();
123             sqlStr.Append("update " + entity.GetType().Name);
124             sqlStr.Append(" set ");
125             sqlStr.Append(fields.Substring(0,fields.Length-1));
126             sqlStr.Append(" where ");
127             sqlStr.Append(primaryKey + "=@" + primaryKey);
128 
129             int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray());
130             if (res > 0)
131                 return true;
132             else
133                 return false;
134         }
135 
136         /// <summary>
137         /// 刪除一條數據
138         /// </summary>
139         /// <param name="connection">連接字符串</param>
140         /// <param name="primaryKey">主鍵值</param>
141         /// <returns></returns>
142         public virtual bool Delete(string connection, object primarykey)
143         {
144             #region 參數
145             T entity = new T();
146 
147             string primaryKey = GetPrimarykey(connection, entity);
148             List<SqlParameter> parameters = new List<SqlParameter>();
149             parameters.Add(new SqlParameter("@" + primaryKey, primarykey)); 
150             #endregion
151 
152             StringBuilder sqlStr = new StringBuilder();
153             sqlStr.Append("delete from ");
154             sqlStr.Append(entity.GetType().Name);
155             sqlStr.Append(" where ");
156             sqlStr.Append(primaryKey + "=@" + primaryKey);
157 
158             int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray());
159             if (res > 0)
160                 return true;
161             else
162                 return false;
163         }
164 
165         /// <summary>
166         /// 刪除多條數據
167         /// </summary>
168         /// <param name="connection">連接字符串</param>
169         /// <param name="base_idlist">主鍵值列表</param>
170         /// <returns></returns>
171         public virtual bool DeleteList(string connection, List<object> primarykeys)
172         {
173             #region 參數
174             T entity = new T();
175 
176             string primaryKey = GetPrimarykey(connection, entity);
177 
178             string primaryKeys = "";
179             foreach(var item in primarykeys)
180             {
181                 primaryKeys += item.ToString();
182             }
183 
184             List<SqlParameter> parameters = new List<SqlParameter>();
185             parameters.Add(new SqlParameter("@" + primaryKey, primaryKeys));
186             #endregion
187 
188             StringBuilder sqlStr = new StringBuilder();
189             sqlStr.Append("delete from ");
190             sqlStr.Append(entity.GetType().Name);
191             sqlStr.Append(" where ");
192             sqlStr.Append(primaryKey + " in(@" + primaryKey + ")");
193 
194             int res = DatabaseAccess.SqlHelper.ExecteNonQueryText(connection, sqlStr.ToString(), parameters.ToArray());
195             if (res > 0)
196                 return true;
197             else
198                 return false;
199         }
200 
201         /// <summary>
202         /// 得到一個對象實體
203         /// </summary>
204         /// <param name="connection">連接字符串</param>
205         /// <param name="primarykey">主鍵值</param>
206         /// <returns></returns>
207         public virtual T GetModel(string connection, object primarykey)
208         {
209             #region 參數
210             T entity = new T();
211 
212             string primaryKey = GetPrimarykey(connection, entity);
213 
214             List<SqlParameter> parameters = new List<SqlParameter>();
215             parameters.Add(new SqlParameter("@table", entity.GetType().Name));
216             parameters.Add(new SqlParameter("@" + primaryKey, primarykey)); 
217             #endregion
218 
219             StringBuilder sqlStr = new StringBuilder();
220             sqlStr.Append("select * from ");
221             sqlStr.Append(entity.GetType().Name);
222             sqlStr.Append(" where ");
223             sqlStr.Append(primaryKey + "=@" + primaryKey);
224 
225             return Common.ToList.TableToList<T>(DatabaseAccess.SqlHelper.ExecuteDataSetText(connection, sqlStr.ToString(), parameters.ToArray()).Tables[0]).FirstOrDefault();
226         }
227 
228         /// <summary>
229         /// 獲得數據列表
230         /// </summary>
231         /// <param name="connection">連接字符串</param>
232         /// <param name="strWhere">查詢條件</param>
233         /// <returns></returns>
234         public virtual List<T> GetList(string connection, string strWhere)
235         {
236             #region 參數
237             T entity = new T();
238 
239             List<SqlParameter> parameters = new List<SqlParameter>();
240             parameters.Add(new SqlParameter("@where", strWhere));
241             #endregion
242 
243             StringBuilder sqlStr = new StringBuilder();
244             sqlStr.Append("select * from ");
245             sqlStr.Append(entity.GetType().Name);
246             if (strWhere.Trim().Length > 0)
247                 sqlStr.Append(" where @where");
248 
249             return Common.ToList.TableToList<T>(DatabaseAccess.SqlHelper.ExecuteDataSetText(connection, sqlStr.ToString(), parameters.ToArray()).Tables[0]);
250         }
251 
252         /// <summary>
253         /// 獲得總數
254         /// </summary>
255         /// <param name="connection">連接字符串</param>
256         /// <param name="strWhere">查詢條件</param>
257         /// <returns></returns>
258         public virtual int GetRecordCount(string connection, string strWhere)
259         {
260             #region 參數
261             T entity = new T();
262 
263             List<SqlParameter> parameters = new List<SqlParameter>();
264             parameters.Add(new SqlParameter("@where", strWhere));
265             #endregion
266 
267             StringBuilder sqlStr = new StringBuilder();
268             sqlStr.Append("select count(1) FROM ");
269             sqlStr.Append(entity.GetType().Name);
270             if (strWhere.Trim().Length > 0)
271                 sqlStr.Append(" where @where");
272 
273             return int.Parse(DatabaseAccess.SqlHelper.ExecuteScalarText(connection, sqlStr.ToString(), parameters.ToArray()).ToString());
274         }
275 
276         /// <summary>
277         /// 執行sql語句
278         /// </summary>
279         /// <param name="connection"></param>
280         /// <param name="cmdtype"></param>
281         /// <param name="sql"></param>
282         /// <param name="parameters"></param>
283         /// <returns></returns>
284         public virtual int ExecteNonQuerySQL(string connection, CommandType cmdtype, string sql, params SqlParameter[] parameters)
285         {
286             return DatabaseAccess.SqlHelper.ExecteNonQuery(connection, cmdtype, sql, parameters);
287         }
288 
289         /// <summary>
290         /// 獲取類主鍵
291         /// </summary>
292         /// <param name="connection">連接字符串</param>
293         /// <param name="entity">類</param>
294         /// <returns></returns>
295         public virtual string GetPrimarykey(string connection, T entity)
296         {
297             StringBuilder sqlStr = new StringBuilder();
298             sqlStr.Append("EXEC sp_pkeys @table_name='" + entity.GetType().Name + "'");
299 
300             SqlParameter[] parameters = new SqlParameter[]
301             {
302                
303             };
304 
305             return DatabaseAccess.SqlHelper.ExecuteDataSetText(connection,sqlStr.ToString(),parameters).Tables[0].Rows[0]["COLUMN_NAME"].ToString();
306         }
307 
308         /// <summary>
309         /// 執行sql語句
310         /// </summary>
311         /// <param name="connection"></param>
312         /// <param name="cmdtype"></param>
313         /// <param name="sql"></param>
314         /// <param name="parameters"></param>
315         /// <returns></returns>
316         public virtual DataSet ExecuteDataSetSQL(string connection, CommandType cmdtype, string sql, params SqlParameter[] parameters)
317         {
318             return DatabaseAccess.SqlHelper.ExecuteDataSet(connection, cmdtype, sql, parameters);
319         }
320     }

View Code

這些方法中默認表都是有主鍵的,而且實體名稱和表名一致,否則執行會報錯.

這套方法已經被我用在一個舊項目的改造中,目前來看效果還是不錯的,因此在這與大家分享,因為本人水平有限,而且沒用太多時間去完善,這套代碼肯定會有很多瑕疵,希望高手不吝賜教.

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