C#實(shí)現(xiàn)用戶登錄功能

1、C#實(shí)現(xiàn)用戶登錄功能usingSystem;usingSystem.Collections.Generic;usingSystem.ComponentModel;usingSystem.Data;usingSystem.Drawing;usingSystem.Linq;usingSystem.Text;usingSystem.Windows.Forms;usingMrCy.BaseClass;/引入文件夾BaseClassusingSystem.Data.SqlClient;/引入連接數(shù)據(jù)庫所需的類namespaceMrCypublicpartialclassfrmLogin:Formpubl

2、icfrmLogin()InitializeComponent();/<summary>/用戶點(diǎn)擊“登錄”觸發(fā)的事件/</summary>/<paramname="sender"></param>/<paramname="e"></param>privatevoidbtnLogin_Click(objectsender,EventArgse)trystringUserName=txtUserName.Text.Trim();/獲取用戶名stringPassWord=txtPwd.Te

3、xt.Trim();/獲取密碼if(UserName="")/如果用戶名為空值MessageBox.Show("請(qǐng)輸入用戶名","提示",MessageBoxButtons.OK,MessageBoxIcon.Information);/彈出消息對(duì)話框elseif(PassWord="")/如果密碼為空值MessageBox.Show("請(qǐng)輸入密碼","提示",MessageBoxButtons.OK,MessageBoxIcon.Information);/彈出消息對(duì)話框e

4、lseSqlConnectionconn=DBconn.Connection();/創(chuàng)建數(shù)據(jù)庫連接對(duì)象conn.Open();/打開數(shù)據(jù)庫連接stringstr="selectcount(*)fromtb_UserwhereUserName='"+UserName+"'andUserPwd*+Password+;/建立查詢數(shù)據(jù)庫中tb_User表的用戶名和對(duì)應(yīng)密碼的SQL字符串SqlCommandcmd=newSqlCommand(str,conn);/創(chuàng)建命令對(duì)象;/SqlDataReadersdr=cmd.ExecuteReader();/創(chuàng)建

5、數(shù)據(jù)讀取器對(duì)象/sdr.Read();/讀取數(shù)據(jù)intn=(int)cmd.ExecuteScalar();if(n>=1)/判斷是否有匹配的用戶名和密碼stringstr1="select*fromtb_UserwhereUserName='"+UserName+"'"/根據(jù)用戶名查詢tb_User表中數(shù)據(jù)cmd=newSqlCommand(str1,conn);/創(chuàng)建命令對(duì)象;SqlDataReadersdr=cmd.ExecuteReader();/創(chuàng)建數(shù)據(jù)讀取器對(duì)象sdr.Read();/讀取數(shù)據(jù)stringUserPowe

6、r=sdr"Power".ToString().Trim();/獲取數(shù)據(jù)庫中tb_User表的Power字段sdr.Close();/關(guān)閉數(shù)據(jù)讀取器conn.Close();/關(guān)閉數(shù)據(jù)庫連接frmMainMain=newfrmMain();/建立主窗體對(duì)象Main.Uname=UserName;/將用戶名賦值給frmMain窗體的Unam對(duì)象Main.Utime=DateTime.Now.ToString();/獲取登錄時(shí)間并賦值給主窗體的Utime對(duì)象Main.Upower=UserPower;/將用戶權(quán)限賦值給主窗體的對(duì)象UpowerMain.Show();/顯示frm

7、Main窗體this.Hide();/隱藏當(dāng)前登錄窗體elseMessageBox.Show("用戶名或密碼錯(cuò)誤","警告",MessageBoxButtons.OK,MessageBoxIcon.Warning);/彈出警告提示框catch(Exceptionex)/拋出異常MessageBox.Show(ex.Message);/彈出消息對(duì)話框/<summary>/單擊“取消”按鈕，清空文本框內(nèi)容/</summary>/<paramname="sender"></param>/<

8、;paramname="e"></param>privatevoidbtnCancel_Click(objectsender,EventArgse)/txtUserName.Text=""/txtPwd.Text=""if(MessageBox.Show("確定退出本系統(tǒng)嗎？","提示",MessageBoxButtons.OKCancel,MessageBoxIcon.Exclamation)=DialogResult.OK)/如果點(diǎn)擊了消息對(duì)話框中的“確定”Applicat

9、ion.Exit();/退出應(yīng)用程序/<summary>Ill當(dāng)用戶輸入用戶名之后判斷是否按了Enter”鍵，按了的話就激發(fā)登錄”按鈕的Click事件/</summary>lll<paramname="sender"><lparam>lll<paramname="e"><lparam>privatevoidtxtUserName_KeyPress(objectsender,KeyPressEventArgse)if(e.KeyChar=13)btnLogin_Click(sender,e);lll<summary>lll當(dāng)用戶輸完密碼，判斷用戶是否按了“Enter”鍵，按了就調(diào)用登錄事件lll<lsummary>lll<paramname="sender"><lparam>