1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Threading.Tasks;
 9 using System.Windows.Forms;
10 using System.Data.SqlClient;
11 
12 namespace Chapter13
13 {
14     public partial class Form1 : Form
15     {
16         public Form1()
17         {
18             InitializeComponent();
19         }
20 
21         private void Form1_Load(object sender, EventArgs e)
22         {
23             //SqlConnection conn = new SqlConnection(@"server=.\SQLEXPRESS;integrated security=true;database=MyBookInfo");
24 
25             //SqlCommand cmd = new SqlCommand();
26 
27             //try
28             //{
29             //    conn.Open();
30 
31             //    txtComandText.AppendText("Connection opened \n");
32             //    txtComandText.AppendText("Command created.\n");
33 
34             //    cmd.CommandText = @"select * from BookInfo ";
35 
36             //    txtComandText.AppendText("Ready to execute SQL Statement:\n\t\t\t" + cmd.CommandText);
37             //}
38             //catch(SqlException ex)
39             //{
40             //    MessageBox.Show(ex.Message + ex.StackTrace, "Exception Details");
41             //}
42             //finally
43             //{
44             //    conn.Close();
45             //    txtComandText.AppendText("\nConnection Closed.");
46             //}
47             
48         }
49 
50         private void btnRowCount_Click(object sender, EventArgs e)
51         {
52             SqlConnection conn = new SqlConnection(@"server=.\SQLEXPRESS;integrated security=true;database=MyBookInfo");
53             
54             //创建连接字符串，conn

55 
56             string sql = @"select count(*) from BookInfo";
57             
58             //sql连接语句
59 
60             SqlCommand cmd = new SqlCommand(sql, conn);
61             
62             //执行连接命令
63 
64             txtScalar.AppendText("Command created and connected.\n");
65 
66             try
67             {
68                 conn.Open();
69                 txtScalar.AppendText("Number of Books is :");
70 
71                 txtScalar.AppendText(cmd.ExecuteScalar().ToString());
72                 txtScalar.AppendText("\n");
73 
74             }
75             catch(SqlException ex)
76             {
77                 MessageBox.Show(ex.ToString());
78             }
79             finally
80             {
81                 conn.Close();
82                 txtScalar.AppendText("\nConnection Closed.");
83             }
84         }
85     }
86 }