ADO.NET 数据查询和数据操作 

 1     //数据查询 DT-PC\\SQLEXPRESS
 2         public static DataTable MyQuery(string str)
 3         {
 4             SqlConnection conn = new SqlConnection("data source=.; database=LJC0125_web; Integrated Security=SSPI");
 5             conn.Open();
 6             SqlDataAdapter da = new SqlDataAdapter(str, conn);
 7             DataTable dt = new DataTable();
 8             da.Fill(dt);
 9             conn.Close();
10             return dt;
11         }
12     //数据操作
13         public static int MyExcute(string str)
14         {
15             SqlConnection conn = new SqlConnection("data source=.; database=LJC0125_web; Integrated Security=SSPI");
16             conn.Open();
17             //创建执行对象
18             SqlCommand cmd = new SqlCommand(str, conn);
19             //3.执行操作，返回受影响的行数
20             int i = cmd.ExecuteNonQuery();
21             //关闭连接
22             conn.Close();
23             //返回受影响行数
24             return i;
25         }

 

 1  //对表的操作
 2      private void Form3_Load(object sender, EventArgs e)
 3         {
 4             //在数据集中添加表
 5             DataTable tbl = new DataTable("user");
 6             ds.Tables.Add(tbl);
 7 
 8             //定义表的列
 9             DataColumn col = tbl.Columns.Add("id", typeof(Int32));
10             col.AutoIncrement = true;
11             col.AutoIncrementSeed = 0;
12             col.AutoIncrementStep = 1;
13             col.ReadOnly = true;
14 
15             tbl.Columns.Add("name", typeof(String));
16             tbl.Columns.Add("birthday", typeof(DateTime));
17 
18             //定义id列为表的主键
19             tbl.PrimaryKey = new DataColumn[] { tbl.Columns["id"] };
20 
21             //添加三行相同的数据
22             for (int i = 0; i < 3; i++)
23             {
24                 DataRow row = tbl.NewRow();
25                 row[1] = "llx";
26                 row[2] = DateTime.Now;
27                 tbl.Rows.Add(row);
28             }
29 
30             //显示到DataGridView控件中
31             dataGridView1.DataSource = ds.Tables["user"];
32 
33 
34         }
35 
36         //添加一行
37         private void button1_Click(object sender, EventArgs e)
38         {
39             DataTable tbl = ds.Tables["user"];
40             DataRow row = tbl.NewRow();
41             row[1] = textBox1.Text;
42             row[2] = dateTimePicker1.Value;
43             tbl.Rows.Add(row);
44         }
45 
46 
47         //删除最后一行
48         private void button2_Click(object sender, EventArgs e)
49         {
50             DataTable tbl = ds.Tables["user"];
51             if (tbl.Rows.Count > 0)
52             {
53                 DataRow row = tbl.Rows[tbl.Rows.Count - 1];
54                 tbl.Rows.Remove(row);
55             }
56         }
57 
58         //修改行
59         private void button3_Click(object sender, EventArgs e)
60         {
61             string s = "";
62 
63             string s = ""
64 
65             //查找特定行，进行修改
66             DataTable tbl = ds.Tables["user"];
67             DataRow row = tbl.Rows.Find(dataGridView1.CurrentRow.Cells[0].Value);
68 
69             if (row != null)
70             {
71                 s += "未修改前为：" + row[1].ToString();
72                 if (textBox1.Text == "")
73                     row[1] = DBNull.Value;
74                 else
75                     row[1] = textBox1.Text;
76                 s += " 修改后为：" + row[1].ToString();
77             }
78 
79             label1.Text = s;
80 
81             
82         }

 

posted on 2014-03-31 13:58  钟灵毓秀的家园  阅读(294)  评论(0)    收藏  举报

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