Question

c#如何做跟数据库相连的登录界面判断？

Answer 1

try
{
if (textBox1.Text == "")
{
MessageBox.Show("用户名不能为空");
}
else
{
if (textBox2.Text == "")
{
MessageBox.Show("密码不能为空!");
}
else
{
string admin_id = textBox1.Text;//获取账号
string admin_psw = textBox2.Text;//获取密码
string conn = "Data Source=LJQA2ILTGDR8QRN;Initial Catalog=admin_login;Integrated Security=True";//连接字符串，需要改成你自己的
SqlConnection connection = new SqlConnection(conn);//创建连接
connection.Open();//打开连接
string sql = string.Format("select count(*) from admin where admin_id='{0}' and admin_psw='{1}'", admin_id , admin_psw);//查询是否有该条记录，根据账户密码
SqlCommand command = new SqlCommand(sql, connection);//sqlcommand表示要向向数据库执行sql语句或存储过程
int i = Convert.ToInt32(command.ExecuteScalar());//执行后返回记录行数
if (i > 0)//如果大于1，说明记录存在，登录成功
{
MessageBox.Show("登录成功！");
Form3 f3 = new Form3();
this.Close();
f3.ShowDialog();
}
else
{
MessageBox.Show("用户名或者密码错误！");
}
connection.Close();
}

}
}
catch (Exception ex)
{
MessageBox.Show("异常错误" + ex);
}