private void button1_Click(object sender, EventArgs e)
{
if (textBox1.Text == "" || textBox2.Text == "")
MessageBox.Show("提示：请输入用户名和密码！");
SqlConnection conn = new SqlConnection(Myclass.strConnection);//建立数据库连接
conn.Open();//打开连接
SqlCommand cmd = new SqlCommand("select * from login where username = '******' and password = '******'", conn);//建立命令对象。查询输入的用户名密码是否在数据库中
SqlDataReader sdr = cmd.ExecuteReader();
sdr.Read();
if (sdr.HasRows)
{
sdr.Close();
string sql20 = "select auth_type from login where username = '******' and password = '******'";//查询登录权限
SqlCommand cmd20 = new SqlCommand(sql20, conn);//建立命令对象
string auth_type = (string)cmd20.ExecuteScalar();//通过executescalar方法返回单值
Myclass.auth_type = auth_type;
switch (Myclass.auth_type)
{
case ("00"):
MessageBox.Show("提示：您将以系统管理员身份登录，请慎重操作！");
break;
case ("01"):
MessageBox.Show("提示：您将以审核者身份登录，请慎重操作！");
break;
case ("10"):
MessageBox.Show("提示：您将以数据录入者身份登录，请慎重操作！");
break;
case ("11"):
MessageBox.Show("提示：您将以普通用户身份登录，无法写数据库！");
break;
}
search_engine f2 = new search_engine();
f2.Show();
this.Hide();
}
else
{
MessageBox.Show("提示：用户名或密码错误！");
textBox1.Text = "";
textBox2.Text = "";
}
sdr.Close();
conn.Close();//关闭连接。对象并释放所占内存空间
}
private void button5_Click(object sender, EventArgs e)
{
search_engine se = new search_engine();
se.Show();
}