三层从理论到实践
这几天画图，很迷茫也不知道怎么画。昨天天找了一个三层的例子画了一下图。有了点感觉，话就不多说了这接上图如下图：
包图
类图
用户查询时序图
用户删除时序图
用户修改时序图
用户注册时序图
界面：
代码：
实体层代码。
Public Class UserInfo
Private userID As Integer
Private userName As String
Private userActor As String
Private userPwd As String
Private userRegDate As DateTime
Private userFlag As Boolean
'用户编号属性
Public Property UserID() As Integer
Get
Return userID
End Get
Set(ByVal value As Integer)
userID = value
End Set
End Property
'用户姓名属性
Public Property UserName() As String
Get
Return userName
End Get
Set(ByVal value As String)
userName = value
End Set
End Property
'用户角色
Public Property UserActor() As String
Get
Return userActor
End Get
Set(ByVal value As String)
userActor = value
End Set
End Property
'用户密码
Public Property UserPwd() As String
Get
Return userPwd
End Get
Set(ByVal value As String)
userPwd = value
End Set
End Property
'用户注册日期
Public Property UserRegDate() As DateTime
Get
Return userRegDate
End Get
Set(ByVal value As DateTime)
userRegDate = value
End Set
End Property
'用户合法标致
Public Property UserFlag
Get
Return userFlag
End Get
Set(ByVal value)
userFlag = value
End Set
End Property
End Class
DAL层代码。
ImportsSystem.Data.SqlClient
'DAL包中的DALuser类。
Public Class DALUser
'数据库连接字符串
Dim connStr As String = "DataSource=192.168.24.63;Initial Catalog=PCharge_Sys;User ID=sa;Password=sa"
''' <summary>
''' 添加一条用户信息
''' </summary>
''' <paramname="EntityUserInfo">一个用户对象</param>
''' <returns>是否添加成功</returns>
''' <remarks>2012年1月19号20：31</remarks>
Public Function DALUserAdd(ByValEntityUserInfo As Entity.UserInfo) As Boolean
Dim sql As String = "Insert intoUserInfo(UserID,UserName,UserActor,UserPwd,UserRegDate,UserFlag)" _
& " values(@UserID,@UserName,@UserActor,@UserPwd,@UserRegDate,@UserFlag) "
Dim conn As SqlConnection = NewSqlConnection(connStr)
Dim cmd As SqlCommand = NewSqlCommand(sql, conn)
Dim sqlParam As New SqlParameter
sqlParam = NewSqlParameter("@UserID", SqlDbType.Int)
sqlParam.Value = EntityUserInfo.UserID
cmd.Parameters.Add(sqlParam)
sqlParam = NewSqlParameter("@UserName", SqlDbType.VarChar)
sqlParam.Value =EntityUserInfo.UserName
cmd.Parameters.Add(sqlParam)
sqlParam = NewSqlParameter("@UserActor", SqlDbType.VarChar)
sqlParam.Value =EntityUserInfo.UserActor
cmd.Parameters.Add(sqlParam)
sqlParam = NewSqlParameter("@UserPwd", SqlDbType.VarChar)
sqlParam.Value = EntityUserInfo.UserPwd
cmd.Parameters.Add(sqlParam)
sqlParam = NewSqlParameter("@UserRegDate", SqlDbType.DateTime)
sqlParam.Value =EntityUserInfo.UserRegDate
cmd.Parameters.Add(sqlParam)
sqlParam = NewSqlParameter("@UserFlag", SqlDbType.Bit)
sqlParam.Value =EntityUserInfo.UserFlag
cmd.Parameters.Add(sqlParam)
Try
conn.Open()
Return cmd.ExecuteNonQuery() > 0
Catch ex As Exception
Return False
End Try
If Not IsNothing(conn) Then
conn.Close()
conn = Nothing
End If
End Function
End Class
BLL层代码。
Imports DAL
''' <summary>
''' BLL包中的BLLUser类。
''' </summary>
'''<remarks></remarks>
Public Class BLLUser
''' <summary>
''' 插入一条用户信息
''' </summary>
''' <paramname="EntityUserInfo"></param>
''' <returns></returns>
''' <remarks></remarks>
Public Function BLLUserAdd(ByValEntityUserInfo As Entity.UserInfo) As Boolean
Dim DALUserInfo As New DAL.DALUser
ReturnDALUserInfo.DALUserAdd(EntityUserInfo)
End Function
End Class
UI层代码。
界面层。
'界面层。
Public ClassUserAddForm
''' <summary>
''' 用户注册，并对用户的输入加以判断。
''' </summary>
''' <paramname="sender"></param>
''' <paramname="e"></param>
''' <remarks></remarks>
Private Sub RegisterBut_Click(ByVal senderAs System.Object, ByVal e As System.EventArgs) Handles RegisterBut.Click
If txtUserID.Text = "" OrtxtUserName.Text = "" Or txtUserPwd.Text = "" OrtxtUserRegDate.Text = "" Or txtUserActor.Text = "" OrtxtUserFlag.Text = "" Then
MsgBox("输入不能为空！请重新输入！")
Else
If Not IsNumeric(txtUserID.Text)Then
MsgBox("输入的编号因为数字！请重新输入！")
End If
If Not IsDate(txtUserRegDate.Text)Then
MsgBox("输入的注册日期请为日期XXXX-XX-XX格式!")
Else
Dim EntityUserInfo As NewEntity.UserInfo
EntityUserInfo.UserID =txtUserID.Text
EntityUserInfo.UserName =txtUserName.Text
EntityUserInfo.UserActor =txtUserActor.Text
EntityUserInfo.UserPwd =txtUserPwd.Text
EntityUserInfo.UserRegDate =txtUserRegDate.Text
EntityUserInfo.UserFlag =txtUserFlag.Text
Dim BLLUserInfo As NewBLL.BLLUser
IfBLLUserInfo.BLLUserAdd(EntityUserInfo) Then
MsgBox("添加成功！")
Else
MsgBox("添加失败！")
End If
End If
End If
End Sub
End Class
上面是在数据库表中插入一条记录，其他的删除和修改，查询类似，就是DAL和BLL层返回值可能不同。
DAL层删除查询代码，保存备后用。
''' <summary>
''' 获得所有用户
''' </summary>
'''<returns>所有用户的DataSet集合</returns>
''' <remarks></remarks>
Public Function DALUserSelectAll() AsDataSet
Dim sql As String = "select * fromUserInfo"
Dim conn As SqlConnection = NewSqlConnection(connStr)
Dim cmd As SqlCommand = NewSqlCommand(sql, conn)
Dim dap As SqlDataAdapter = NewSqlDataAdapter(cmd)
Dim ds As New DataSet
Try
conn.Open()
dap.Fill(ds)
Return ds
Catch ex As Exception
Return Nothing
Finally
If Not IsNothing(cmd) Then
cmd.Dispose()
cmd = Nothing
End If
If Not IsNothing(conn) Then
conn.Close()
conn = Nothing
End If
End Try
End Function
''' <summary>
''' 获得一个用户的信息。
''' </summary>
''' <paramname="UserID"></param>
''' <returns>一个用户的对象</returns>
''' <remarks></remarks>
Public Function DALUserGetObject(ByValUserID As Integer) As Entity.UserInfo
Dim sql As String = "selectUserName,UserActor,UserPwd,UserRegDate,UserFlag from UserInfo whereUserID=@UserID"
Dim conn As SqlConnection = NewSqlConnection(connStr)
Dim cmd As SqlCommand = NewSqlCommand(sql, conn)
Dim sqlParam As NewSqlParameter("@UserID", SqlDbType.Int)
sqlParam.Value = UserID
Dim sdr As SqlDataReader = Nothing
Dim DALEntityUserinfo As NewEntity.UserInfo
Try
sdr = cmd.ExecuteReader()
While sdr.Read
DALEntityUserinfo.UserID =UserID
DALEntityUserinfo.UserName =sdr.GetString(0)
DALEntityUserinfo.UserActor =sdr.GetString(1)
DALEntityUserinfo.UserPwd =sdr.GetString(2)
DALEntityUserinfo.UserRegDate =sdr.GetString(3)
DALEntityUserinfo.UserFlag =sdr.GetString(4)
End While
Return DALEntityUserinfo
Catch ex As Exception
Return Nothing
Finally
If Not IsNothing(sdr) Then
sdr.Close()
sdr = Nothing
End If
If Not IsNothing(cmd) Then
cmd.Dispose()
cmd = Nothing
End If
If Not IsNothing(conn) Then
conn.Close()
conn = Nothing
End If
End Try
End Function
Public Function DALUserDel(ByValDALEntityUserinfo As Entity.UserInfo) As Boolean
Dim sql As String = "delete fromUserInfo where UserID=@UserID"
Dim conn As SqlConnection = NewSqlConnection(connStr)
Dim cmd As SqlCommand = NewSqlCommand(sql, conn)
Dim sqlParam As NewSqlParameter("@UserID", SqlDbType.Int)
sqlParam.Value =DALEntityUserinfo.UserID
Try
conn.Open()
Return cmd.ExecuteNonQuery() > 0
Catch ex As Exception
Return False
Finally
If Not IsNothing(cmd) Then
cmd.Dispose()
cmd = Nothing
End If
If Not IsNothing(conn) Then
conn.Close()
conn = Nothing
End If
End Try
End Function
End Class
这个是来自一篇博客连接如下：http://www.cnblogs.com/loveyong/archive/2012/01/20/2330144.html