C#系统登录

登录界面：Login.csusingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Text;usingSystem.Windows.Forms;namespaceWindowsApplication3{publicpartialclassLogin:Form{publicLogin(){InitializeComponent();}privatevoidbtnYes_Click(objectsender,EventArgse){stringuserName=txtName.Text;stringpassword=txtPwd.Text;if(userName==伍晓忠&&password==1234){MessageBox.Show(欢迎进入成绩管理系统！,登陆成功,MessageBoxButtons.OK,MessageBoxIcon.Information);}else{MessageBox.Show(你输入的用户名或密码错误！,登录失败,MessageBoxButtons.OK,MessageBoxIcon.Exclamation);}}privatevoidbtnCancel_Click(objectsender,EventArgse){txtName.Text=;txtPwd.Text=;txtName.Focus();}}}创建数据库：实现登录功能usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Text;usingSystem.Windows.Forms;usingSystem.Data.SqlClient;namespaceWindowsApplication3{publicpartialclassLogin:Form{publicLogin(){InitializeComponent();}privatevoidbtnYes_Click(objectsender,EventArgse){stringuserName=txtName.Text;stringpassword=txtPwd.Text;//stringconnString=@DataSource=YJ\sqlexpress;InitialCatalog=MySchool;IntegratedSecurity=Ture;;stringconnString=@DataSource=深度系统\sqlexpress;InitialCatalog=MySchool;trusted_connection=true;;//pc-200907051235\sqlexpressSqlConnectionconnection=newSqlConnection(connString);//获取用户名和密码匹配的行的数量的SQL语句stringsql=String.Format(selectcount(*)from[User]whereuserName='{0}'andpassword='{1}',userName,password);try{connection.Open();//打开数据库连接SqlCommandcommand=newSqlCommand(sql,connection);//创建Command对象intnum=(int)command.ExecuteScalar();//执行查询语句，返回匹配的行数if(num0){//如果有匹配的行，则表明用户名和密码正确MessageBox.Show(欢迎进入成绩管理系统！,登陆成功,MessageBoxButtons.OK,MessageBoxIcon.Information);MainFrmmainForm=newMainFrm();//创建主窗体对象mainForm.Show();//显示窗体this.Visible=false;//登陆窗体隐藏}else{MessageBox.Show(你输入的用户名或密码错误！,登录失败,MessageBoxButtons.OK,MessageBoxIcon.Exclamation);}}catch(Exceptionex){MessageBox.Show(ex.Message,操作数据库出错！,MessageBoxButtons.OK,MessageBoxIcon.Exclamation);}finally{connection.Close();}}privatevoidbtnCancel_Click(objectsender,EventArgse){txtName.Text=;txtPwd.Text=;txtName.Focus();}privatevoidLogin_Load(objectsender,EventArgse){}}}主窗体创建代码：usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Text;usingSystem.Windows.Forms;namespaceWindowsApplication3{publicpartialclassMainFrm:Form{publicMainFrm(){InitializeComponent();}privatevoidMainFrm_Load(objectsender,EventArgse){}}}