? ? ?在上上篇。《機房收費系統重構（3）》。中主要是介紹了自己關于DAL層，工廠層。以及接口層，還有實體層的理解。可是好多讀者再問我。你的代碼呢，我在這解釋一下。就是我僅僅是寫出關于那幾部分的理解，并沒有寫貼出代碼讓大家研究的。可是不能順應民心的文章不是好文章，所以我在這篇文章中，將機房收費登錄中七層中全部的代碼，貼出來供大家拍磚斧正。還有最后我在談談針對BLL層和外觀層的理解。

? ? ?首先我所說的七層是針對UI層，外觀層，BLL層，DAL層，工廠層，實體層，接口層七層組成。

? ? ?實現登錄窗口，要明確。先要查詢用戶是否存在，然后將登錄信息寫入數據庫，這兩個主要步驟。

首先來看看我數據庫中用到的兩個表：

??

? ? 這樣能方便讀者更easy理解后面的代碼：

? ? 一.首先看看實體層的代碼吧

（1）用戶表實體層：

Public Class MO_LoginPrivate _userID As StringPrivate _level As StringPrivate _password As StringPrivate _userName As StringPrivate _computer As StringPublic Shared UserHead As String ' 設置全局變量Public Shared UserLevel As StringPublic Property UserID() As StringGetReturn _userIDEnd GetSet(value As String)_userID = valueEnd SetEnd PropertyPublic Property PassWord() As StringGetReturn _passwordEnd GetSet(value As String)_password = valueEnd SetEnd PropertyPublic Property level() As StringGetReturn _levelEnd GetSet(value As String)_level = valueEnd SetEnd PropertyPublic Property UserName() As StringGetReturn _userNameEnd GetSet(value As String)_userName = valueEnd SetEnd PropertyPublic Property Computer() As StringGetReturn _computerEnd GetSet(value As String)_computer = valueEnd SetEnd Property End Class（2）工作記錄實體層：

Public Class MO_WorklogPrivate _userID As StringPrivate _level As StringPrivate _loginDataTime As StringPrivate _computer As StringPrivate _status As StringPublic Shared Property Login_DataTime As StringPublic Property UserID() As StringGetReturn _userIDEnd GetSet(value As String)_userID = valueEnd SetEnd PropertyPublic Property level() As StringGetReturn _levelEnd GetSet(value As String)_level = valueEnd SetEnd PropertyPublic Property LoginDataTime() As StringGetReturn _loginDataTimeEnd GetSet(value As String)_loginDataTime = valueEnd SetEnd PropertyPublic Property Computer() As StringGetReturn _computerEnd GetSet(value As String)_computer = valueEnd SetEnd PropertyPublic Property Status() As StringGetReturn _statusEnd GetSet(value As String)_status = valueEnd SetEnd Property End Class? ?二.接著來看看UI層的吧：

Public Class frmLoginPrivate Sub btnOK_Click(sender As Object, e As EventArgs) Handles btnOK.ClickDim login As New Model.MO_LoginDim falogin As New Facade.FA_Login '實例化過程Dim strResult As Stringlogin.UserID = txtUserName.Text '賦值過程login.PassWord = txtPassWord.TextModel.MO_Login.UserHead = txtUserName.TextDim worklog As New Model.MO_Worklog '實例化工作記錄worklog.LoginDataTime = Date.Now.ToString("yyyy-mm-dd hh:mm:ss") '上機時間worklog.Status = "正在值班" '工作狀態worklog.UserID = Model.MO_Login.UserHeadworklog.Computer = System.Net.Dns.GetHostName().ToString() '本地計算機strResult = falogin.FLogin(login, worklog) '傳參返回過程Select Case strResult '推斷過程Case "輸入有誤"MsgBox("輸入有誤。請又一次輸入")Case "登錄成功"MsgBox("登錄成功")Model.MO_Worklog.Login_DataTime = worklog.LoginDataTimeMe.Hide()'frmMain.Show()End SelectEnd SubPrivate Sub btnCancel_Click(sender As Object, e As EventArgs) Handles btnCancel.ClickEndEnd Sub End Class ? ?三.外觀層代碼：

Imports BLL Public Class FA_LoginPublic Function FLogin(ByVal user As Model.MO_Login, worklog As Model.MO_Worklog) As StringDim UserBLL As New BLL.BL_LoginIf UserBLL.IsnotNull(user, worklog) = False ThenReturn "輸入有誤"ElseReturn "登錄成功"End IfEnd Function End Class ? ?四.BLL層代碼：<pre name="code" class="vb">Imports IDAL Public Class BL_LoginPublic Function IsnotNull(ByVal user As Model.MO_Login, ByVal worklog As Model.MO_Worklog) As BooleanDim IUser As IDAL.ILogin '注意接口類型不能實例化。Dim factory As New Factory.LoginFactory '實例化工廠Dim IWorklog As IDAL.IWorklogIUser = factory.CreateUserInfo() '工廠創建接口，DAL實現接口。BLL調用工廠IWorklog = factory.CreateWorklog()If IUser.User_Login(user).UserID = "" Then '假設為空Return False 'Boolean值為falseElseworklog.level = IUser.User_Login(user).level '傳參數。將查詢到的用戶類型傳給worklog實體層。在后面的增刪改中應用。

If IWorklog.SaveWorkLog(worklog) Then '假設查詢到用戶存在，就開始將登錄信息寫入數據庫中。

Return True End If Return True End If End Function End Class

? 五.工廠層代碼：

Imports System.Reflection '加入反射的引用 Imports System.Configuration '加入配置文件的引用 Imports IDAL Public Class LoginFactory'利用反射+配置文件+抽象工廠Dim strDB As String = System.Configuration.ConfigurationSettings.AppSettings("strSqlConnection")'表示讀取配置文件。假設配置文件里是SQLserver數據庫就訪問，假設是別的就放訪問別的，不須要更改代碼'Dim strQueryWorkLog As String = System.Configuration.ConfigurationSettings.AppSettings("strSqlConnection")'創建用戶表工廠Public Function CreateUserInfo() As ILoginReturn CType(Assembly.Load("DAL").CreateInstance("DAL" & "." & "DA_Login"), ILogin)End FunctionPublic Function CreateWorklog() As IWorklogReturn CType(Assembly.Load("DAL").CreateInstance("DAL" & "." & "DA_Worklog"), IWorklog)End FunctionEnd Class? 六.接口層代碼：

（1）用戶查詢接口

Public Interface ILoginFunction User_Login(ByVal user As Model.MO_Login) As Model.MO_Login End Interface（2）將操作記錄寫入數據庫代碼：

Public Interface IWorklogFunction SaveWorkLog(ByVal worklog As Model.MO_Worklog) As Boolean End Interface? 七.最后是DAL層代碼：

（1）用戶查詢DAL

Imports System.Data.SqlClient Imports System.Data Imports IDAL Public Class DA_Login : Implements IDAL.ILoginPublic Function User_Login(user As Model.MO_Login) As Model.MO_Login Implements IDAL.ILogin.User_LoginDim sqlparams As SqlParameter() = {New SqlParameter("@UserID", user.UserID), New SqlParameter("@Password", user.PassWord)} '傳遞參數過程Dim cmdText As String = "select * from T_UserInfo where UserName =@UserID and PassWord =@Password" '查詢數據庫Dim aUser As New Model.MO_Login '實例化過程Dim helper As New SqlHelperDim cmdType As CommandType = New CommandType()cmdType = CommandType.Text '定義命令類型為存儲過程Dim table As DataTable '實例化一個過程'在這里想解釋一個，因為函數返回參數是實體層。可是這里定義的table是一個Datable類型。所以系統無法進行轉換。

所以我定義了一個aUser進行中轉。 table = helper.ExecuteQuery(cmdText, cmdType, sqlparams) '定義返回值 If table.Rows.Count <> 0 Then aUser.UserID = table.Rows(0).Item("UserID") aUser.PassWord = table.Rows(0).Item("PassWord") aUser.level = table.Rows(0).Item("level") aUser.UserName = table.Rows(0).Item("UserName") End If Return aUser End Function End Class

（2）操作記錄寫入代碼DAL

Imports System.Data.SqlClient Imports System.Data Imports IDAL Public Class DA_Worklog : Implements IDAL.IWorklogPublic Function SaveWorkLog(worklog As Model.MO_Worklog) As Boolean Implements IWorklog.SaveWorkLogDim strText As String = "INSERT INTO T_WorkLog(UserID,level,LoginDateTime,Computer,Status)VALUES (@UserID,@level,@LoginDateTime,@Computer,@Status)"Dim sqlparams As SqlParameter() = {New SqlParameter("@UserID", worklog.UserID), New SqlParameter("@level", worklog.level), New SqlParameter("@LoginDateTime", worklog.LoginDataTime), New SqlParameter("@Computer", worklog.Computer), New SqlParameter("@Status", worklog.Status)}Dim cmdType As CommandType = CommandType.TextDim helper As New SqlHelperReturn helper.ExecuteNonQuery(strText, cmdType, sqlparams)End Function End Class ? ? ??事實上這些代碼也不全。少了關于工廠反射的配置部分的內容，還有就是SqlHelper。

SqlHelper，在我《機房收費重構（4）》中有非常具體的介紹。

在這就不寫了。

? ? 最后說一下關于BLL和外觀層的理解吧。從代碼看。仿佛感覺外觀層沒有什么作用，是的，關于登錄窗口小功能的實現，沒有太大的必要用外觀層，可是以后要敲一個龐大的窗口時，我們須要將U層和B層解耦，那么外觀層的作用就彰顯出來了。關于BLL和外觀事實上沒有什么想說的。最想說的是數據類型的轉換，由于層與層之間傳遞參數和返回參數的過程須要用到相同類型的數據，可是將數據類型都設置為Datatable和string或者實體類型是不可能。希望大家在今后寫程序過程中注意就能夠了。

? ?本片文章代碼較多。希望大家拍磚斧正。。

總結

以上是生活随笔為你收集整理的机房收费系统重构（五）—登陆窗口完整版的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。