1  private static SqlConnection connection;
 2 
 3         //根据web.config得到一个SqlConnection
 4         public static SqlConnection Connection
 5         {
 6             get
 7             {
 8               string connectionString = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;
 9                 if (connection == null)
10                 {
11                     connection = new SqlConnection(connectionString);
12                     connection.Open();
13                 }
14                 else if (connection.State == System.Data.ConnectionState.Closed)
15                 {
16                     connection.Open();
17                 }
18                 else if (connection.State == System.Data.ConnectionState.Broken)
19                 {
20                     connection.Close();
21                     connection.Open();
22                 }
23                 return connection;
24             }
25         }
26          //得到无参一个表
27         public static DataTable GetDataSet(string safeSql)
28         {
29             DataSet ds = new DataSet();
30             SqlCommand cmd = new SqlCommand(safeSql, Connection);
31             SqlDataAdapter da = new SqlDataAdapter(cmd);
32             da.Fill(ds);
33             if (connection != null)
34             {
35                 connection.Close();
36                 connection.Dispose();
37                 connection = null;
38             }
39 
40             return ds.Tables[0];
41             
42         }