第四章 ADO.NET

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows.Forms;using System.Data.SqlClient;namespace WindowsFormsApplication1{ ???public partial class Form1 : Form ???{ ???????public Form1() ???????{ ???????????InitializeComponent(); ???????} ???????private void Form1_Load(object sender, EventArgs e) ???????{ ???????????//定义一个需要访问的数据库的信息 ???????????string strCon = "Server=PC-20161029WDCV\\SQL2014;Database=StudentDB;Trusted_Connection=True"; ???????????SqlConnection con = new SqlConnection(strCon); ???????????//打开数据库连接 ???????????con.Open(); ???????????string cmdText = "select * from course"; ???????????SqlDataAdapter da = new SqlDataAdapter(cmdText, con); ???????????//新建一个DataSet，用于接收查询结果 ???????????DataSet ds = new DataSet(); ???????????da.Fill(ds); ???????????//关闭数据库连接 ???????????con.Close(); ???????????//将查询结果的第一个表赋值给dt ???????????DataTable dt = ds.Tables[0]; ???????????txtMsg.Text = "课程号 ???课程名\r\n"; ???????????????????????//foreach (DataRow dr in dt.Rows) ???????????//{ ???????????// ???txtMsg.Text += dr[0].ToString() + " ??" + dr[1].ToString()+"\r\n"; ???????????//} ???????????for (int i = 0; i < dt.Rows.Count; i++) ???????????{ ???????????????txtMsg.Text += dt.Rows[i][0] + " ???" + dt.Rows[i][1] + "\r\n"; ???????????} ???????????lblMsg.Text = "共" + dt.Rows.Count + "条数据"; ???????????//txtMsg.Text += dt.Rows[0][0].ToString() + " ???"+dt.Rows[0]["课程名"].ToString(); ???????} ???}}