VB.NET三层登陆

前端之家收集整理的这篇文章主要介绍了VB.NET三层登陆前端之家小编觉得挺不错的,现在分享给大家,也给大家做个参考。

之前用C#敲过一次三层登录,在用C#敲三层登录的时候已经将基本信息给介绍的比较全面了,所以这次用VB.NET敲完三层,也不做过多的介绍,只在这里将敲完三层所用的VB.NET的代码展示一下,有需要的可以借鉴一下,在第一次用VB.NET敲三层感到迷惑的时候可以参考这篇博客来实现一下代码这也是我写这篇博客的主要目的,给大家带来帮助。OK,废话不说了,看代码

一开始敲的时候,最好是将DAL层敲好,DAL层可以分为两部分,第一部分是将数据库和VS连接上:代码如下

  1. Imports System.Data
  2. Imports System.Data.sqlClient
  3.  
  4. Public Class UbUtil
  5. Public Shared Function Connstring() As sqlConnection
  6. Dim cnStr As String
  7. cnStr = "server=.;database=Login;User ID=sa;password=123"
  8. Dim coon As sqlConnection
  9. coon = New sqlConnection(cnStr)
  10. Return coon
  11. End Function
  12. End Class

然后再将DAL层的第二部分敲好。DAL第二部分的作用是用来接收BLL层所发出的信息然后再与数据库中相应位置的信息匹配,代码如下:

  1. Imports System.Data
  2. Imports System.Data.sqlClient
  3.  
  4. Public Class Selectsql
  5. Public Function SelectUserInfo(UserInfo As Model.UserInfo) As Model.UserInfo
  6. Dim cn As sqlConnection = sqlHelper.Connstring
  7. Dim sql As String
  8. sql = "SELECT * from Users where UserName = @UserName and Password = @Password"
  9. Dim cmd As sqlCommand = New sqlCommand(sql,cn)
  10. cmd.Parameters.Add(New sqlParameter("@UserName",UserInfo.UserName))
  11. cmd.Parameters.Add(New sqlParameter("@Password",UserInfo.Password))
  12. cn.Open()
  13. Dim reader As sqlDataReader
  14. reader = cmd.ExecuteReader()
  15. Dim User As New Model.UserInfo
  16. While (reader.Read())
  17. User.UserName = reader.GetString(1)
  18. User.Password = reader.GetString(2)
  19. End While
  20. Return UserInfo
  21. End Function
  22. End Class

这样DAL层就已经大功告成,接下来就是敲Model模块,Model模块的作用就是连接整个流程,在敲完这个模块之后,再敲BLL层的话,就能顺利的让BLL层与DAL层成功连接,方便一步一步的调试,所以Model层的重要性是非常大的,代码如下:

  1. Public Class Login.UserInfo
  2. Private Property e_userName As String
  3. Public Property UserName() As String
  4. Get
  5. Return e_userName
  6. End Get
  7. Set(value As String)
  8. e_userName = value
  9. End Set
  10. End Property
  11. Private Property e_Password As String
  12. Public Property Password() As String
  13. Get
  14. Return e_Password
  15. End Get
  16. Set(value As String)
  17. e_Password = value
  18. End Set
  19. End Property
  20. End Class

等Model模块敲完之后就可以继续敲BLL层了,BLL的作用是用来处理业务逻辑的,起到一个承上启下的作用。具体代码如下:

  1. Public Class LoginManager
  2. Public Function checkUserinfo(ByVal UserInfo As Model.UserInfo) As Model.UserInfo
  3. Dim Login As New DAL.Selectsql
  4. Dim Manager As New Model.UserInfo
  5. Manager = Login.SelectUserInfo(UserInfo)
  6. If (Manager.UserName Is Nothing Or Manager.Password Is Nothing) Then
  7. Throw New Exception("用户名或密码错误,请核实~~~")
  8. End If
  9. MsgBox("登陆成功,正在登录系统",MsgBoxStyle.Information + MsgBoxStyle.OkOnly,"提示")
  10. Return Manager
  11. End Function
  12. End Class

最后就剩下UI层了,我所做的显示窗体是这样的:


其具体的代码如下:

  1. Imports System.Windows.Forms
  2. Public Class Login
  3. Private Sub btnOK_Click(sender As Object,e As EventArgs) Handles btnOK.Click
  4. Try
  5. Dim UserInfo As New Model.UserInfo
  6. UserInfo.UserName = txtUserName.Text.Trim()
  7. UserInfo.Password = txtPassword.Text.Trim()
  8. If txtUserName.Text = "" Then
  9. MsgBox("用户名不能为空!","提示")
  10. Return
  11. End If
  12. If txtPassword.Text = "" Then
  13. MsgBox("密码不能为空!","提示")
  14. Return
  15. End If
  16. Dim Login As New BLL.Manager
  17. Dim returnUserInfo As New Model.UserInfo
  18. returnUserInfo = Login.checkUserinfo(UserInfo)
  19. Catch ex As Exception
  20. MessageBox.Show(ex.Message.ToString())
  21. End Try
  22. End Sub
  23. End Class

大功告成,这就是VB.NET敲下的三层登录所有的代码,具体数据库的设置看代码应该能看出一些,数据库建立了一个表,表名为:Users

希望能帮大到家。

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