【正文】 雙主鍵，并且主鍵值均為整型。第三章 詳細(xì)設(shè)計(jì)本系統(tǒng)集成了“登錄”模塊，因此在系統(tǒng)加載時(shí)，需要先啟動“登錄”模塊的“登錄”窗體，只有用戶輸入了正確的用戶名和密碼后才能進(jìn)入到系統(tǒng)。主窗體首先啟動“登錄”窗體，“登錄”窗體運(yùn)行界面如圖1所示：圖1代碼如下：Public Class LOGIN Inherits Public flag = False Private Sub btok_Click(ByVal sender As , ByVal e As ) Handles If () = Then (姓名不能為空) () ElseIf () = Then (密碼不能為空) () Else Dim sql As String = SELECT * FROM USERINFO WHERE USERID = 39。 + () + 39。 AND USERPWD = 39。 + () + 39。 Dim dt As DataTable = GetDataTable(sql) If = 0 Then (用戶名不存在或密碼不正確) () Else UserRight = (0)(usertype) UserID = () flag = True () End If End If End Sub Private Sub btcancel_Click(ByVal sender As , ByVal e As ) Handles () End Sub登陸成功后，并不是所有的菜單對所有用戶來說都是可見的，在本系統(tǒng)中，共有三個角色，按不同角色登錄后，運(yùn)行的主窗體是不同的。登錄成功后顯示主窗體，“系統(tǒng)管理員登陸后”界面如圖2所示：圖2代碼如下：Public Class FrmMain Inherits Region Windows 窗體設(shè)計(jì)器生成的代碼End Region Private Sub FrmMain_Load(ByVal sender As Object, ByVal e As ) Handles Dim check As Boolean = True Try Do Dim Login As New LOGIN () If = And Then check = False ElseIf = Then () check = False End If Loop While check If UserRight = 1 Then = False ElseIf UserRight = 2 Then = False = False End If Catch ex As Exception WriteErr(ex) End Try End Sub Private Sub user_Click(ByVal sender As , ByVal e As ) Handles Dim FrmUser As New FrmUser = Me () End Sub Private Sub CourseMan_Click(ByVal sender As , ByVal e As ) Handles Dim FrmCourse As New FrmCourse = Me () End Sub Private Sub StudentMan_Click(ByVal sender As , ByVal e As ) Handles Dim FrmStudent As New FrmStudent = Me () End Sub Private Sub ClassMan_Click(ByVal sender As , ByVal e As ) Handles Dim FrmClass As New FrmClass = Me () End Sub Private Sub DepartmentMan_Click(ByVal sender As , ByVal e As ) Handles Dim FrmDep As New FrmDepartment = Me () End Sub Private Sub ResultMan_Click(ByVal sender As , ByVal e As ) Handles Dim FrmResult As New FrmResult = Me () End Sub Private Sub ResultQuery_Click(ByVal sender As , ByVal e As ) Handles Dim FrmQuery As New FrmQuery = Me () End Sub Private Sub Changemypwd_Click(ByVal sender As , ByVal e As ) Handles Dim ChangePwd As New ChangePwd () End Sub Private Sub Exitme_Click(ByVal sender As , ByVal e As ) Handles = False = False = False = False End Sub Private Sub Relogin_Click(ByVal sender As , ByVal e As ) Handles Dim check As Boolean = True Try Do Dim Login As New LOGIN () If = And Then check = False ElseIf = Then () check = False End If Loop While check If UserRight = 0 Then = True = True = True ElseIf UserRight = 1 Then = True = True ElseIf UserRight = 2 Then = True End If Catch ex As Exception WriteErr(ex) End Try End SubEnd Class“信息管理員登錄后”界面如圖3所示：圖3“信息查詢員登陸后”界面如圖4所示：圖4窗體運(yùn)行后。將在“用戶管理”窗體中顯示所有的用戶信息?！坝脩艄芾怼贝绑w在運(yùn)行中的界面如圖5所示代碼如下：Imports Imports Public Class FrmUser Inherits Dim Usertype As Int16 Dim UserPwd As StringRegion Windows 窗體設(shè)計(jì)器生成的代碼 End Region Private Sub FrmUser_Load(ByVal sender As Object, ByVal e As ) Handles BindData() End Sub Public Sub BindData() Try Dim sql As String = select userid as 39。用戶名39。,userpwd as 39。用戶密碼39。,usertype as 39。用戶權(quán)限39。 from userinfo Dim dt As DataTable = GetDataTable(sql) = dt = 用戶名 Catch ex As Exception WriteErr(ex) End Try End Sub Private Sub DeleteData() Dim sql As String = DELETE FROM USERINFO WHERE USERID= 3