嵌入SQL语句

嵌入SQL语言:

 

我将一个sql链接到数据库，该数据库名为master(系统数据库)

 

then 给数据库添加新表，建立三个key：userid(int),name(char(10)),password(char(10))

 

在窗体中弄三个textbox控件，分别定义Name属性为userid,name,password;

再来一个button

 

以下是Form1.cs中的代码

 using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Data.OleDb;using System.Windows.Forms;using System.Data.SqlClient;using System.Runtime.InteropServices;using System.Configuration;namespace Str{ public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void submit_Click(object sender, EventArgs e) { /* * connect to Sql Server * 方法一：写在这里 */ //string strConnection = "Data Source=ZRQ-PC;"; //strConnection += "Initial Catalog=master;Integrated Security=True"; // SqlConnection objConnection = new SqlConnection(strConnection); /* * 方法二： * 这个方法为工程添加了新建项“应用程序配置文件” * 将上面的那段写在App.config里 */ string strConnection = ConfigurationSettings.AppSettings["connectionstring"]; SqlConnection objConnection = new SqlConnection(strConnection); /************************************************************************/ if (name.Text == "") MessageBox.Show("请输入姓名!", "提示", 0); else { objConnection.Open(); SqlCommand cmd = new SqlCommand("select * from judging where userid='" + userid.Text.Trim() + "'", objConnection); /* *********************************************************************************************** *判断是否有重复的ID,ExecuteScalar() return the first column of the first row in the result set. */ if (cmd.ExecuteScalar() != null) { MessageBox.Show("ID重复", "提示", 0); } else { string sql = "insert into judging (userid,name,password) values('" + userid.Text.Trim() + "','" + name.Text.Trim() + "','" + password.Text.Trim() + "')"; cmd.CommandText = sql; cmd.ExecuteNonQuery(); MessageBox.Show("添加成功！"); } name.Clear(); password.Clear(); userid.Clear(); } objConnection.Close(); } }}/**另外，在设计页面想设置password这个textbox显示为*：讲passwordchar属性写为**另外，设置submit按钮为默认按钮：在form属性中的acceptbutton写为默认按钮的Name:submit*/

 

以下是.config中的代码：

 

<?xml version="1.0" encoding="utf-8" ?><configuration> <appSettings> <add key="connectionstring" value="Data Source=ZRQ-PC;Initial Catalog=master;Integrated Security=True;" /> </appSettings></configuration>