机房收费——七层

七层，顾名思义就是把一个窗体分层七块，上篇博客我们分析了三层，那么七层也就是在三层的基础上，再加上四层。

这入住新家的四层是什么呢？这个就可以因人而异了，因为我们之前学过大话，那么这四层，我们就可以从大话借了，因为我比较不聪明，所以我就遵循常规，和大多数一样用最常见的七层了。

先看看我的七层有什么。

接着看他们的关系

如图，可知，我们首先要解决的依旧是实体层。

 Public Class User
     Private name As String
     Private password As String
     Private Userid As String
     Private level As String
     Private account As String
 '以下为可读写属性
     Public Property user_name() As String
         Get
             Return name
         End Get
         Set(ByVal value As String)
             name = value
         End Set
     End Property
     Public Property user_id() As String
         Get
             Return Userid
         End Get
         Set(ByVal value As String)
             Userid = value
         End Set
     End Property
     Public Property user_pwd() As String
         Get
             Return password
         End Get
         Set(ByVal value As String)
             password = value
         End Set
     End Property
     Public Property user_level() As String
         Get
             Return level
         End Get
         Set(ByVal value As String)
             level = value
         End Set
     End Property
     Public Property user_account() As String
         Get
             Return account
         End Get
         Set(ByVal value As String)
             account = value
         End Set
     End Property
 End Class

接着，我们就可以发现，联系最多，关系最密集的就是ＩＤＡＬ接口。我们新建一个接口类，然后

 Public Interface IUserInfo
     '查询用户的接口函数
     Function QueryUserInfo(ByVal user As Entity.UserInfo) As Entity.UserInfo

 End Interface

有了接口，我们就可以从后往前写了，ＤＡＬ

 Public Class T_UserDAL : Implements IUser
     '/// <summary>
     '/// depiction：<查询用户名和密码是否正确>
     '/// </summary>
     '/// <param name="<enUser>"><用户实体></param>
     '/// <returns>
     '///<返回一个用户实体的集合>
     '/// </returns>
     Public Function SelectUser(ByVal enUser As Entity.UserEntity) As List(Of Entity.UserEntity) Implements IUser.SelectUser
         Dim strText As String = "select * from T_User where UserID=@UserID and password=@password"  'sql语句
         Dim cmdType As CommandType = CommandType.Text   '命令类型
         Dim Parameter As SqlParameter()
         '传参
         Parameter = {New SqlParameter("@UserID", enUser.userID),
                      New SqlParameter("@password", enUser.password)}

         Dim SqlHelper As New SqlHelper  '实例化SqlHelper这个类的一个对象
         Dim dt As New DataTable
         Dim myList As List(Of Entity.UserEntity)

         dt = SqlHelper.ExecuteReaderTable(strText, cmdType, Parameter) '调用sqlhelper中executereadertable的方法
         myList = EntityHelper.convertToList(Of Entity.UserEntity)(dt)

         Return myList
     End Function

 End Class

然后就是和他紧密联系的设计模式。工厂１４１页，不懂看看（我也不太懂，呵呵、）

 Imports System.Reflection
 Public Class DataAccess
     '/// <summary>
     '/// depiction：<创建用户接口>
     '/// </summary>
     '/// <param name="<>"><></param>
     '/// <returns>
     '///<返回IUserDAL>
     '/// </returns>
     Public Function CreateIUser() As IDAL.IUser
         Return CType(Assembly.Load("DAL").CreateInstance("DAL.T_UserDAL"), IDAL.IUser)
     End Function
 End Class

接着是逻辑判断的ＢＬＬ

 Public Function SelectUser(ByVal enUser As Entity.UserEntity) As List(Of Entity.UserEntity)
         Dim factory As New Factory.DataAccess
         Dim IUser As IDAL.IUser
         Dim myList As List(Of Entity.UserEntity)

         IUser = factory.CreateIUser()
         myList = IUser.SelectUser(enUser)

         Return myList

     End Function

然后，减负的外观、

  Public Function SelectUser(ByVal enUser As Entity.UserEntity) As List(Of Entity.UserEntity)
         Dim userBLL As New BLL.T_UserBLL
         Dim myList As List(Of Entity.UserEntity)

         myList = userBLL.SelectUser(enUser)

         If myList.Count = 0 Then
             Throw New Exception("用户名或密码输入错误")
         Else
             Return myList
         End If
     End Function

最后，就是见人的ＵＩ

  Private Sub btnConfirm_Click(sender As Object, e As EventArgs) Handles btnConfirm.Click
         Dim facade As New Facade.LoginFacade
         Dim myList As New List(Of Entity.UserEntity)
         Dim enUser As New Entity.UserEntity      '封装实体
         Dim flag As Boolean
         Try
             enUser.userID = txtUserName.Text.Trim()
             enUser.password = txtPassword.Text.Trim()

             myList = facade.SelectUser(enUser)

             If myList.Count > 0 Then
                 MsgBox("登录成功")

                 Dim enWorklog As New Entity.WorklogEntity
                 enWorklog.userID = txtUserName.Text.Trim()
                 enWorklog.loginDate = CStr(Format(Now(), "yyyy-MM-dd"))
                 enWorklog.loginTime = CStr(Format(Now(), "HH:mm:ss"))
                 enWorklog.status = "正在值班"
                 enWorklog.computer = Environment.GetEnvironmentVariable("USERNAME")

                 flag = facade.InsertWorklog(enWorklog)

                 enLogin.userID = myList.Item(0).userID
                 enLogin.level = myList.Item(0).level

             End If
         Catch ex As Exception
             MessageBox.Show(ex.Message.ToString())
             txtUserName.Focus()
             txtUserName.SelectAll()
             txtPassword.Text = ""

         End Try
     End Sub
     Private Sub btnCancel_Click(sender As Object, e As EventArgs) Handles btnCancel.Click
         Me.Close()
     End Sub