用户登录

[c#]代码库

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

using Common;
using System.Data.SqlClient;

namespace Pos
{
    public partial class frmMLogin : Form
    {
        public frmMLogin()
        {
            InitializeComponent();
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            if (txtLoginId.Text == "")
            {
                MessageBox.Show("你必须输入用户ID！", "输入提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                txtLoginId.Focus();
                return;
            }

            if (txtLoginPwd.Text == "")
            {
                MessageBox.Show("你必须输入用户密码！", "输入提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                txtLoginPwd.Focus();
                return;
            }

            
            LoginMain();
        }

        private void LoginMain()
        {
            string loginId = txtLoginId.Text.Trim();

            string loginPwd = txtLoginPwd.Text;
            string sql = string.Format("select * from vw_right where User_code='{0}' and User_pwd='{1}' and mod_Name='{2}'", loginId, loginPwd, "前台收银");
            DataTable dt1 = SQLHelper.ExecuteDataSet(sql).Tables[0];
            if ( dt1.Rows.Count > 0 )
            {
                PUser.UserCode = loginId;
                PUser.UserPass = loginPwd;
                PUser.UserName = dt1.Rows[0]["User_name"].ToString();
                PUser.RoleID = dt1.Rows[0]["role_id"].ToString();
                PUser.RoleName = dt1.Rows[0]["role_name"].ToString();

                string sql2 = string.Format("select * from front_duty where User_code='{0}' and Duty_endTime is null", loginId);
                DataTable dt2 = SQLHelper.ExecuteDataSet(sql2).Tables[0];
                if (dt2.Rows.Count > 0)
                {
                    PUser.dutyID = dt2.Rows[0]["duty_id"].ToString();
                }

                frmMain frm = new frmMain();
                frm.Show();
                this.Hide();
            }
            else
            {
                MessageBox.Show("用户名或密码出错，或者无操作权限！", "登录失败", MessageBoxButtons.OK, MessageBoxIcon.Error);
                txtLoginId.Focus();
                return;
            }

        }

        private void txtName_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                if (txtLoginId.Text.Trim().Length > 0)
                {
                    txtLoginPwd.Focus();
                }
                else
                {
                    MessageBox.Show("你必须输入用户ID！", "输入提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    txtLoginId.Focus();
                    //return;
                }
            }
        }

        private void txtPassword_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
            {
                LoginMain();
            }
        }

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

[代码运行效果截图]