C#操作SQLServer的一个简单封装

 1 class DBHandler {
 2 
 3     //SqlConnection数据库连接对象
 4     private SqlConnection localConnection = null;
 5 
 6     //构造函数中初始化连接对象，传入数据库服务名，数据库实例名，用户名和密码
 7     public DBHandler(string server, string dataBase, string id, string pwd) { 
 8         String connectionString = "Data Source=" + server + ";Initial Catalog=" + dataBase
 9                                 + ";User ID=" + id + ";Password=" + pwd;
10         this.localConnection = new SqlConnection(connectionString);
11     }
12 
13     //创建对象后调用该方法判断是否能够成功连接
14     public int checkValidate(ref string errMsg) {
15         try {
16             this.localConnection.Open();
17         } catch (Exception ex) {
18             errMsg = "[Connecting failed]" + ex.Message;
19             return -1;
20         }
21         return 0;
22     }
23 
24     //操作数据库前调用
25     private void prepareConnect() {
26         switch (this.localConnection.State) {
27             case ConnectionState.Broken:
28                 this.localConnection.Close(); //先正常关闭，释放资源
29                 this.localConnection.Open();
30                 break;
31             case ConnectionState.Closed:
32                 this.localConnection.Open();
33                 break;
34             case ConnectionState.Connecting:
35                 break;
36             case ConnectionState.Executing:
37                 break;
38             case ConnectionState.Fetching:
39                 break;
40             case ConnectionState.Open:
41                 break;
42             default:
43                 break;
44         }
45     }
46 
47     //执行Update语句，返回更新的行数
48     public int doUpdate(string sql, ref string errMsg) {
49         prepareConnect();
50         SqlCommand localCommand = new SqlCommand();
51         localCommand.CommandText = sql;
52         localCommand.Connection = this.localConnection;
53         try {
54             return localCommand.ExecuteNonQuery();
55         } catch (Exception ex) {
56             errMsg = "[update error]" + ex.Message;
57             return -1;
58         }
59     }
60 
61     //执行Select语句，返回DataTable结果集
62     public void doSelect(string sql, ref DataTable dataTable, ref string errMsg) {
63         prepareConnect();            
64         try {
65             SqlDataAdapter dataAdapter = new SqlDataAdapter(sql, this.localConnection);
66             dataTable.Clear();
67             dataAdapter.Fill(dataTable);
68         } catch (Exception ex) {
69             errMsg = "[select error]" + ex.Message;
70         }
71     }
72     
73 }