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SQLserver数据库连接问题(wfa程序登录源代码)

 
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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace RLHT_YXJ_WFA1
{
public partial class LogIn : Form
{
//string[] table=new string[20];
public LogIn()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
using (SqlConnection conn = new SqlConnection(@"Data Source=YXJ\SQLEXPRESS;AttachDBFilename=|DataDirectory|\Ceshi.mdf;Integrated Security=True;User Instance=true"))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText="select user_name,user_pwd from Users Where user_name='"+this.textBox1.Text+"'";
using (SqlDataReader reader = cmd.ExecuteReader())
{
if (this.textBox1.Text == "")

MessageBox.Show("请输入您的用户名");
else if (this.textBox2.Text == "")

MessageBox.Show("请输入您的密码");
else if (reader.Read())
{
//用户名存在
string dbpassword = reader.GetString(reader.GetOrdinal("user_pwd"));
if (this.textBox2.Text == dbpassword)
{
//登陆成功
ShowUser showuser = new ShowUser(textBox1.Text);
showuser.Show();
}
else
{
//密码错误
MessageBox.Show("您所输入的密码错误");
this.textBox2.Text = null;
}
}
else
{
//用户名错误
MessageBox.Show("您所输入的用户名不存在");
this.textBox1.Text = null;
}
}
}
conn.Close();
conn.Dispose();
}

//数据访问出现问题,明明修改了数据库,但还是可以用修改前的老用户数据进行访问,是缓存问题?有知道的高手烦请解答。
//DataTable table = new DataTable();
//SqlDataAdapter da = new SqlDataAdapter();

//string connstr = @"Data Source=YXJ\SQLEXPRESS;AttachDBFilename=|DataDirectory|\Ceshi.mdf;Integrated Security=True;User Instance=true";
//SqlConnection connection = new SqlConnection(connstr);
//connection.Open();
//SqlCommand ca = new SqlCommand("select user_name,user_pwd from Users Where user_name='"+this.textBox1.Text+"'",connection);
//da.SelectCommand = ca;
//da.Fill(table);
//if (this.textBox1.Text == "")

// MessageBox.Show("请输入您的用户名");
//else if (this.textBox2.Text == "")

// MessageBox.Show("请输入您的密码");
//else if (table.Rows.Count == 0)
//{
// MessageBox.Show("您所输入的用户名不存在");
// this.textBox1.Text = null;
//}
//else if (table.Rows[0][0].ToString() != this.textBox2.Text)
//{

// MessageBox.Show("您所输入的密码错误");
// this.textBox2.Text = null;
//}
//else
//{
// System.Console.WriteLine(table.Rows[0][0].ToString());
// System.Console.WriteLine(this.textBox2.Text);
// MessageBox.Show(table.Rows[0][0].ToString());
// MessageBox.Show(this.textBox2.Text);

// ShowUser showuser = new ShowUser(textBox1.Text);
// showuser.Show();
//}
//connection.Close();
//table.Clear();

}

private void button3_Click(object sender, EventArgs e)
{
NewUser newuser=new NewUser();
newuser.Show();
}

private void button4_Click(object sender, EventArgs e)
{
textBox1.Clear();
textBox2.Clear();
}

private void button2_Click(object sender, EventArgs e)
{
this.Close();
}
}
}

参考:

SqlDataAdapter

http://baike.baidu.com/view/2978109.htm

DataTable

http://blog.csdn.net/hcw_peter/article/details/3980723

关于|DataDirectory|\:

Program.cs

static void Main()
{

string dataDir = AppDomain.CurrentDomain.BaseDirectory;
if (dataDir.EndsWith(@"\bin\Debug\") || dataDir.EndsWith(@"\bin\Release\"))
{
dataDir = System.IO.Directory.GetParent(dataDir).Parent.Parent.FullName;
AppDomain.CurrentDomain.SetData("DataDirectory", dataDir);
}
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new LogIn());
}

//这是为了在测试运行的时候,让项目里的数据库文件和程序Debug或Release运行里的数据库文件区别开,真正交付给客户的时候一般不需要这段代码。

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