读出的数据是和SQL执行一样的。

这步完成之后，下步就是DATAAPDAPTER对象啦。。。

暂时不弄了，跟小区朋友打篮球先。。。

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 WindowsFormsApplication513 {14     public partial class Form1 : Form15     {16         SqlConnection conn;17         public Form1()18         {19             InitializeComponent();20         }21 22         private void button1_Click(object sender, EventArgs e)23         {24             if (textBox1.Text == "")25             {26                 MessageBox.Show("Please input database name");27             }28             else29             {30                 try31                 {32                     if (conn.State == ConnectionState.Open || textBox1.Text != "")33                     {34                         SqlCommand cmd = new SqlCommand();35                         cmd.Connection = conn;36                         cmd.CommandText = "select * from " + textBox1.Text.Trim();37                         cmd.CommandType = CommandType.Text;38                         SqlDataReader sdr = cmd.ExecuteReader();39                         while (sdr.Read())40                         {41                             richTextBox1.Text += sdr[0].ToString() + "\t";42                             richTextBox1.Text += sdr[1].ToString() + "\t";43                             richTextBox1.Text += sdr[2].ToString() + "\n";44                         }45                         conn.Dispose();46                     }47                 }48                     49                     catch(Exception ex)50                 {51                         MessageBox.Show(ex.Message);52                     }53             }54         }55 56 57 58         private void Form1_Load(object sender, EventArgs e)59         {60             string ConStr = "server = .; database= msdb; uid = A; pwd = B";61             conn = new SqlConnection(ConStr);62             conn.Open();63 64         }65        }66                     67        68     }