VB.NET版+三層實現登陸

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三層已經學了一些時間了，開始認為自己能夠用C#敲代碼了，就用C#寫了一個實現登陸的，真正再用在機房中。還是認為非常吃力的，所以。決定用vb.net敲了。以下是我用vb.net實現的登陸。能夠給大家做一些參考。

  

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  這是構架的三層

  資料庫中的表T_User_DAL：UserI。Level，Password，Head，computer

  首先看一下

                                        Entity層：

Public Class UserInfoEntity#Region "定義變數"    Private _userID As String    Private _level As String    Private _Head As String    Private _password As String#End Region    Public Property UserID() As String            ‘將T_User_DAL表中的每個實體都傳上去，實體是依據表來建的，不是功能        Get            Return _userID        End Get        Set(value As String)            _userID = value        End Set    End Property    Public Property Level() As String        Get            Return _level        End Get        Set(ByVal value As String)            _level = value        End Set    End Property    Public Property Head() As String        Get            Return _Head        End Get        Set(value As String)            _Head = value        End Set    End Property    Public Property Password() As String        Get            Return _password        End Get        Set(value As String)            _password = value        End Set    End PropertyEnd Class

                                        DAL層：

   為了可以減少耦合一定要將連接字串拿出來。不要每個DAL中都寫一邊。

Imports System.DataImports System.Data.SqlClientPublic Class SqlUtil    Public Shared Function connstring() As String        ‘connstring = "Server=192.168.24.183;Database=ReconsitutionCharge_sys;User ID=sa;Password=123456"     ‘會出現無法識別userid的錯誤        connstring = "Server=mx; Database=ReconsitutionCharge_sys; User ID=sa; Password=123456"         ‘串連SQL的字串    End FunctionEnd Class

T_User_dal表DAL層代碼：

Imports System.Data.SqlClientImports System.DataPublic Class UserDAL    Public Function SelectUser(ByVal user As Entity.UserInfoEntity) As Entity.UserInfoEntity        Dim conn As New SqlConnection                          ‘定義串連開啟資料庫        Dim cmd As New SqlCommand                              ‘定義資料庫命令        conn = New SqlConnection(SqlUtil.connstring())         ‘執行個體化SQLUntil中返回的字串         cmd.Connection = conn        cmd.CommandText = "Select * From T_User_DAL Where [email protected] and [email protected]"        ‘預存程序        cmd.Parameters.Add(New SqlParameter("@UserID", user.UserID))                        ‘賦值，傳參        cmd.Parameters.Add(New SqlParameter("@Password", user.Password))        cmd.CommandType = CommandType.Text                                                  ‘CommandText 屬性設定為預存程序的名稱。當調用 Execute 方法之中的一個時，該命令將運行此預存程序        conn.Open()                                                                         ‘開啟串連        Dim reader As SqlClient.SqlDataReader                                               ‘讀取資料庫中的表        reader = cmd.ExecuteReader()        Dim users As New Entity.UserInfoEntity                                              ‘執行個體化實體        While (reader.Read())            ‘If users Is Nothing Then            ‘    user = New Entity.UserInfoEntity            ‘End If            users.UserID = reader.GetString(reader.GetOrdinal("UserID"))            users.Password = reader.GetString(reader.GetOrdinal("Password"))        End While        conn.Close()        Return users    End FunctionEnd Class

                                        BLL層：

Public Class LoginBLL    Function UserLogin(ByVal user As Entity.UserInfoEntity) As Entity.UserInfoEntity        Dim uDAL As New DAL.UserDAL                                 ‘執行個體化了DAL中的UserDAL        Dim users As New Entity.UserInfoEntity                      ‘執行個體化了Entity層資訊表        users = uDAL.SelectUser(user)                               ‘selectUser是返回一個Entity類的，給它賦值user        Return users                                                ‘返回users實體    End FunctionEnd Class

                                        UI層：

    介面設計：

    

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   Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click        Dim mgr As New BLL.LoginBLL             ‘執行個體業務層        Dim user As New Entity.UserInfoEntity   ‘執行個體實體        Dim users As Entity.UserInfoEntity      ‘接收實體，用於接收UserLogin（）返回的資料類型，假設沒有New就不是執行個體化        user.UserID = txtUserID.Text.Trim()     ‘給實體層傳入值        user.Password = TxtPassword.Text.Trim()        If txtUserID.Text = "" Then             ‘推斷輸入是否正確            MsgBox("username不可為空！")            Return        End If        If TxtPassword.Text = "" Then            MsgBox("password不可為空！")            Return        End If        Try                                    ‘users接收實體            users = mgr.UserLogin(user)            If (users.UserID Is Nothing And users.Password Is Nothing) Then      ‘假設users不為空白。則登陸成功！                MsgBox("登陸失敗，username和password不匹配")                Return            Else                MsgBox("登陸成功。登陸使用者：" + user.UserID)            End If        Catch ex As Exception            MsgBox(ex.Message())        End Try    End SubEnd Class

VB.NET版+三層實現登陸