C#_连接数据库实现 登录注册界面

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; using System.Data.SqlClient; namespace LoginDatabase { public partial class Login : Form { private int errorTime = 3; public Login() { InitializeComponent(); } private void loginBtn_Click(object sender, EventArgs e) { errorTime = errorTime - 1; string username = txtName.Text.Trim(); //取出账号 string pw = txtPwd.Text.Trim(); //取出密码 string constr = "Server=.;DataBase=SU; Integrated Security=True"; //设置连接字符串 SqlConnection mycon = new SqlConnection(constr); //实例化连接对象 mycon.Open(); SqlCommand mycom = mycon.CreateCommand(); //创建SQL命令执行对象 string s1 = "select account,password from register where account=‘" + username + "‘ and password=‘" + pw + "‘"; //编写SQL命令 mycom.CommandText = s1; //执行SQL命令 SqlDataAdapter myDA = new SqlDataAdapter(); //实例化数据适配器 myDA.SelectCommand = mycom; //让适配器执行SELECT命令 DataSet myDS = new DataSet(); //实例化结果数据集 int n = myDA.Fill(myDS, "register"); //将结果放入数据适配器，返回元祖个数 if (n != 0) { if (checkCode.Text == textCheck.Text) { MessageBox.Show("欢迎使用！"); //登录成功 this.Close(); } else { MessageBox.Show("验证码填写错误"); textCheck.Text = ""; } } else if (errorTime < 3) { MessageBox.Show("用户名或密码有错。请重新输入！还有" + errorTime.ToString() + "次机会"); txtName.Text = ""; //清空账号 txtPwd.Text = ""; //清空密码? txtName.Focus(); //光标设置在账号上 } else { MessageBox.Show("你输入的用户名或密码已达三次? 将退出程序"); this.Close(); } } private void cancelBtn_Click(object sender, EventArgs e) { Application.Exit(); } private void button1_Click(object sender, EventArgs e) { Register register = new Register(); register.ShowDialog(); } private void checkCode_Click(object sender, EventArgs e) { Random random = new Random(); int minV = 12345, maxV = 98765; checkCode.Text = random.Next(minV, maxV).ToString(); } } } 5.编写注册界面逻辑 using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Data.SqlClient; using System.Drawing; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks; using System.Windows.Forms; namespace LoginDatabase { public partial class Register : Form { public Register() { InitializeComponent(); } private void btnRegister_Click(object sender, EventArgs e) { //检查是否已经存在 string userID = userId.Text.Trim(); //取出账号 /** * 连接数据库 */ string constr = "Server=.;DataBase=SU; Integrated Security=True"; //设置连接字符串 SqlConnection mycon = new SqlConnection(constr); //实例化连接对象 mycon.Open(); //查询新注册的用户是否存在 SqlCommand checkCmd = mycon.CreateCommand(); //创建SQL命令执行对象 string s = "select account from register where account=‘" + userID + "‘"; checkCmd.CommandText = s; SqlDataAdapter check = new SqlDataAdapter(); //实例化数据适配器 check.SelectCommand = checkCmd; //让适配器执行SELECT命令 DataSet checkData = new DataSet(); //实例化结果数据集 int n = check.Fill(checkData, "register"); //将结果放入数据适配器，返回元祖个数 if (n != 0) { MessageBox.Show("用户名存在"); userId.Text = ""; userPw.Text = ""; nickName.Text = ""; } //确认密码 if (ensurePw.Text != userPw.Text) { ensurePw.Text = ""; } //验证码 if (textCheck.Text != checkCode.Text) { textCheck.Text = ""; } //插入数据SQL 逻辑 string s1 = "insert into Register(account,password,nickname) values (‘" + userId.Text + "‘,‘" + userPw.Text + "‘,‘" + nickName.Text + "‘)"; //编写SQL命令 SqlCommand mycom = new SqlCommand(s1, mycon); //初始化命令 mycom.ExecuteNonQuery(); //执行语句 mycon.Close(); //关闭连接 mycom = null; mycon.Dispose(); //释放对象 if (userId.Text == "" || userPw.TextLength <= 6 || nickName.Text == "" || ensurePw.Text == "" || textCheck.Text == "") { MessageBox.Show("请将信息填完整"); } else { MessageBox.Show("注册成功"); this.Close(); } } private void checkCode_Click(object sender, EventArgs e) { Random random = new Random(); int minV = 12345, maxV = 98765; checkCode.Text = random.Next(minV, maxV).ToString(); } }

 

 

 

 

 

 

 

C#_连接数据库实现 登录注册界面

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