这俩天做登陆界面设计，也在网上查了一些资料，发现大部分都是针对某个功能介绍，而很少有完整的案列。我呢就结合自己的需求，把有些功能整合在一起了，欢迎大家修改完善。
SQL数据库设计：
登陆界面设计：
using System;using System.Collections.Generic;using ponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Data.SqlClient;namespace ZH_controls{public partial class Login : Form{public Login(){InitializeComponent();}private void Login_Load(object sender, EventArgs e){}private void Login_Button_Click(object sender, EventArgs e) //单击登陆按钮{String username, password;username = UserName.Text;password = Password.Text;String myconn = "Data Source=PC-0112FRNM;Initial Catalog=属性表;User ID=sa;Password=123;Integrated Security=True";//数据库实例连接字符串SqlConnection sqlConnection = new SqlConnection(myconn);//新建数据库连接实例sqlConnection.Open();//打开数据库连接password = Adduser.GetMD5(password); //在同一个命名空间（在同一个文件夹中），可以访问Adduser里的GetMD5函数。 因为MD5加密算法不可逆，所以要把输入的密码加密和数据库里密码匹配。这样做以后，除了用户自己谁也不知道密码了。String sql = "select UserName,Password from User_info where UserName='" + username + "'and Password='" + password + "'";//SQL语句实现表数据的读取SqlCommand sqlCommand = new SqlCommand(sql, sqlConnection);SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();if (UserName.Text == ""){MessageBox.Show("请输入用户名", "登陆失败");UserName.Focus();}else if (Password.Text == ""){MessageBox.Show("请输入密码", "登陆失败");}else{if (sqlDataReader.HasRows)//满足用户名与密码一致，进入下一个界面{//实现页面跳转Form1 form3 = new Form1();this.Hide();//隐藏当前窗体form3.ShowDialog();Application.ExitThread(); //退出当前窗体，这一步很重要，否则最后可能无法将所有进程关闭。最好是在跳转页面后，将之前的页面退出。}else//如果登录失败，询问是否注册新用户{DialogResult dr = MessageBox.Show("是否注册新用户？", "登录失败", MessageBoxButtons.YesNo, MessageBoxIcon.Question);if (dr == DialogResult.Yes)//打开注册界面{Adduser form2 = new Adduser();this.Hide();form2.ShowDialog();Application.ExitThread(); }else{UserName.Text = "";Password.Text = "";UserName.Focus();this.Show();}}}sqlConnection.Close();}private void Register_Click(object sender, EventArgs e)//单击注册按钮{Adduser form2 = new Adduser();this.Hide();form2.ShowDialog();Application.ExitThread(); }private void Quit_Click(object sender, EventArgs e) //单击退出按钮{Application.Exit(); }private void UserName_KeyPress(object sender, KeyPressEventArgs e) //功能：输入用户名后，按 Enter键，光标到输入密码的TextBox中{if (e.KeyChar == (char)Keys.Enter){Password.Focus();//控制光标指向哪的}}private void Password_KeyPress(object sender, KeyPressEventArgs e) //KeyPress事件，在控件具有焦点并且用户按下并释放某个键后发生{if (e.KeyChar == (char)Keys.Enter){// Login_Button.Focus();Login_Button_Click(sender ,e);}}}}
注册页面设计：
using System;using System.Collections.Generic;using ponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Data.SqlClient;using System.Security.Cryptography; //MD5密码加密 namespace ZH_controls{public partial class Adduser : Form{public Adduser(){InitializeComponent();}private void button1_Click(object sender, EventArgs e) //单击确定按钮{String username, password, repassword;username = textBox1.Text;password = textBox2.Text;repassword = textBox3.Text;if (textBox1.Text == ""){ MessageBox.Show("请输入用户名", "注册失败");textBox1.Focus();}else if (textBox2.Text == ""){MessageBox.Show("请输入密码", "注册失败");textBox2.Focus();}else if (textBox3.Text == "")MessageBox.Show("请确认密码", "注册失败");else{string myConn = "Data Source=PC-0112FRNM;Initial Catalog=属性表;User ID=sa;Password=123;Integrated Security=True";SqlConnection sqlConnection = new SqlConnection(myConn); //实例化连接对象 sqlConnection.Open();String sql = "select UserName from User_info where UserName='" + username + "'";//SQL语句实现表数据的读取SqlCommand sqlCommand = new SqlCommand(sql, sqlConnection);SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();if (sqlDataReader.HasRows){sqlConnection.Close();MessageBox.Show("该用户名已存在，请重新注册", "注册失败");textBox1.Text = "";textBox2.Text = "";textBox3.Text = "";textBox1.Focus();//指定光标在哪个textBox处闪烁}else{if (password == repassword)//两次输入的密码一致 {sqlConnection.Close();string myConn2 = "Data Source=PC-0112FRNM;Initial Catalog=属性表;User ID=sa;Password=123;Integrated Security=True";SqlConnection sqlConnection2 = new SqlConnection(myConn2); //实例化连接对象 sqlConnection.Open();password = GetMD5(password);String sql2 = "INSERT INTO User_info(UserName,Password) VALUES('" + username + "','" + password + "')";//SQL语句向表中写入数据 SqlCommand sqlCommand2 = new SqlCommand(sql2, sqlConnection);sqlCommand2.ExecuteNonQuery();sqlConnection2.Close();DialogResult dr = MessageBox.Show("是否返回主界面", "注册成功", MessageBoxButtons.YesNo, MessageBoxIcon.Question);if (dr == DialogResult.Yes)//打开注册界面{Login form2 = new Login();this.Hide();form2.ShowDialog();Application.ExitThread();}else{textBox1.Text = "";textBox2.Text = "";textBox3.Text = "";this.Show();}}else{MessageBox.Show("两次输入密码不一致", "错误信息");textBox1.Text = "";textBox2.Text = "";textBox3.Text = "";}}} }private void button2_Click(object sender, EventArgs e) //返回登陆按钮{Login form3 = new Login();this.Hide();form3.ShowDialog();Application.ExitThread(); }public static string GetMD5(String input) //MD5算法，输入一段字符串，输出一段字符串{string cl = input;string pwd = "";MD5 md5 = MD5.Create();//实例化一个md5对像// 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择byte[] s = puteHash(Encoding.UTF8.GetBytes(cl));// 通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得for (int i = 0; i < s.Length; i++){// 将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母，如果使用大写（X）则格式后的字符是大写字符 pwd = pwd + s[i].ToString("X");}return pwd;}private void textBox1_KeyPress(object sender, KeyPressEventArgs e) {if (e.KeyChar == (char)Keys.Enter){textBox2.Focus();}}private void textBox2_KeyPress(object sender, KeyPressEventArgs e){if (e.KeyChar == (char)Keys.Enter){textBox3.Focus();}}private void textBox3_KeyPress(object sender, KeyPressEventArgs e){if (e.KeyChar == (char)Keys.Enter){button1_Click(null, null);}}}}
