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重构—组合查询

时间：2015-02-16 10:15:28      阅读：177      评论：0      收藏：0      [点我收藏+]

标签：窗体继承   模板方法组合查询   datatable转化为泛型   

    组合查询是重构中的一个重点，也是比较麻烦的，但是我们可以用一个很好的办法来解决它，比如窗体继承，模板方法。关于窗体继承请参考博文：http://blog.csdn.net/augus3344/article/details/29384877 讲的很详细。这里主要说下模板方法，用这个方法可以为我们省掉很多繁琐的步骤和重复的代码。我们就以父窗体为模板，继承窗体来实现不同的模板，也就是将公共的代码写到模板中，自己特有的代码写到自己的模块，下面看代码。

 

父窗体的代码

 

U层代码

 

ImportsSystem.Windows.Forms
ImportsMicrosoft.Office.Interop.Excel
ImportsMicrosoft.Office.Interop
 
Public ClassfrmComboQueryUI
    Public comboquery As NewEntity.ComboQueryEntity
    Public Overridable Subfrmcomboqueryui_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        MaximizeBox = False
        '将参数传递给实体，赋初值
        '因为不同窗体字段不同，所以赋“”，子窗体重写它
        comboquery.Field1 = ""
        comboquery.Field2 = ""
        comboquery.Field3 = ""
 
        '操作符
       cboOperator1.Items.Add(">")
       cboOperator1.Items.Add("<")
        cboOperator1.Items.Add("=")
       cboOperator1.Items.Add("<>")
 
       cboOperator2.Items.Add(">")
       cboOperator2.Items.Add("<")
        cboOperator2.Items.Add("=")
       cboOperator2.Items.Add("<>")
 
       cboOperator3.Items.Add(">")
       cboOperator3.Items.Add("<")
        cboOperator3.Items.Add("=")
       cboOperator3.Items.Add("<>")
 
        '关系
        cboRelation1.Items.Add("与")
        cboRelation1.Items.Add("或")
 
        cboRelation2.Items.Add("与")
        cboRelation2.Items.Add("或")
 
        '窗体加载后，后两组控件默认不可用
        cboField2.Enabled = False
        cboOperator2.Enabled = False
        txtContent2.Enabled = False
 
        cboRelation2.Enabled = False
 
        cboField3.Enabled = False
        cboOperator3.Enabled = False
        txtContent3.Enabled = False
 
        '设置选中单元格就选中行
        DataGridView1.SelectionMode =DataGridViewSelectionMode.FullRowSelect
        Dim i As Integer
 
        For i = 0 ToDataGridView1.Columns.Count - 1
            DataGridView1.Columns(i).Width =DataGridViewAutoSizeColumnsMode.AllCells
        Next
 
    End Sub
 
    Public Overridable SubbtnQuery_Click(sender As Object, e As EventArgs) Handles btnQuery.Click
        '判断组合框不为空
 
        If cboRelation1.Text = ""Then
            If cboField1.Text = "" OrcboOperator1.Text = "" Or txtContent1.Text = "" Then
               MsgBox("第一行查询条件不能为空，请完善查询信息！", CType(vbOKOnly +MsgBoxStyle.Exclamation, MsgBoxStyle), "提示")
                Exit Sub
            End If
        End If
 
        If cboRelation1.Text <>"" Then
            If cboField1.Text = "" OrcboOperator1.Text = "" Or txtContent1.Text = "" Or
                cboField1.Text = ""Or cboOperator2.Text = "" Or txtContent2.Text = "" Then
               MsgBox("第二行查询条件不能为空，请完善查询信息！", CType(vbOKOnly +MsgBoxStyle.Exclamation, MsgBoxStyle), "提示")
                Exit Sub
            End If
        Else
            If cboRelation2.Text <>"" Then
                If cboField1.Text ="" Or cboOperator1.Text = "" Or txtContent1.Text ="" Or
                cboField2.Text = ""Or cboOperator2.Text = "" Or txtContent2.Text = "" Or
                cboField3.Text = ""Or cboOperator3.Text = "" Or txtContent3.Text = "" Then
 
                   MsgBox("第三行查询条件不能为空，请完善查询信息！", CType(vbOKOnly +MsgBoxStyle.Exclamation, MsgBoxStyle), "提示")
                    Exit Sub
                End If
 
            End If
 
        End If
 
        '将参数传给实体
        comboquery.dbName = GetdbName()
        comboquery.Field1 =ToEnglish(cboField1.Text)
        comboquery.Field2 =ToEnglish(cboField2.Text)
        comboquery.Field3 =ToEnglish(cboField3.Text)
 
        comboquery.Operator1 =cboOperator1.Text.Trim
        comboquery.Operator2 =cboOperator2.Text.Trim
        comboquery.Operator3 =cboOperator3.Text.Trim
 
        comboquery.Content1 =txtContent1.Text.Trim
        comboquery.Content2 =txtContent2.Text.Trim
        comboquery.Content3 =txtContent3.Text.Trim
 
        comboquery.Relation1 =ToEnglish(cboRelation1.Text)
        comboquery.Relation2 =ToEnglish(cboRelation2.Text)
 
        '给B层ComboQuery方法传递参数 
        Dim cboll As New BLL.ComboQueryBLL
        '为了将dt类型转化为泛型
        Dim myquery As New Entity.MyQueryEntity
        '如果没有返回结果
        If cboll.ComboQuery(comboquery) IsNothing Then
            MsgBox("没有记录，请重新设置查询条件",vbOKOnly, vbExclamation)
            DataGridView1.DataSource = Nothing
        Else
            '将结果返回给myquery实体
            myquery =cboll.ComboQuery(comboquery)
           '如果连接的是Linelog表，DataGridView1和LineEntity匹配
            If comboquery.dbName ="Linelog" Then
                DataGridView1.DataSource =myquery.LineEntity
                '设置标题行
               DataGridView1.Columns(0).HeaderText = "卡号"
               DataGridView1.Columns(1).Visible = False
               DataGridView1.Columns(2).Visible = False
               DataGridView1.Columns(3).Visible = False
               DataGridView1.Columns(4).Visible = False
               DataGridView1.Columns(5).Visible = False
               DataGridView1.Columns(6).Visible = False
               DataGridView1.Columns(7).HeaderText = "消费时间"
               DataGridView1.Columns(8).HeaderText = "消费金额"
               DataGridView1.Columns(9).Visible = False
               DataGridView1.Columns(10).HeaderText = "上机时间"
               DataGridView1.Columns(11).HeaderText = "上机日期"
               DataGridView1.Columns(12).HeaderText = "下机时间"
               DataGridView1.Columns(13).HeaderText = "下机日期"
               DataGridView1.Columns(14).HeaderText = "机器名"
            Else
               '如果连接的是v_studentinfo表，DataGridView1和RegisterEntity匹配
                If comboquery.dbName ="v_studentinfo" Then
                    DataGridView1.DataSource =myquery.RegisterEntity
                    '设置标题行
                   DataGridView1.Columns(0).HeaderText = "卡号"
                   DataGridView1.Columns(1).HeaderText = "学号"
                   DataGridView1.Columns(2).HeaderText = "学生姓名"
                   DataGridView1.Columns(3).HeaderText = "性别"
                   DataGridView1.Columns(4).HeaderText = "年级"
                   DataGridView1.Columns(5).HeaderText = "班级"
                   DataGridView1.Columns(6).HeaderText = "专业"
                   DataGridView1.Columns(7).HeaderText = "注册教师"
                   DataGridView1.Columns(8).Visible = False
                   DataGridView1.Columns(9).Visible = False
                   DataGridView1.Columns(10).Visible = False
                   DataGridView1.Columns(11).Visible = False
                Else
                   '如果连接的是WorklogEntity表，DataGridView1和WorklogEntity匹配
                    DataGridView1.DataSource =myquery.WorklogEntity
                    '设置标题行
                   DataGridView1.Columns(0).Visible = False
                   DataGridView1.Columns(1).HeaderText = "教师号"
                   DataGridView1.Columns(2).HeaderText = "机器名"
                   DataGridView1.Columns(3).Visible = False
                   DataGridView1.Columns(4).HeaderText = "上机时间"
                   DataGridView1.Columns(5).HeaderText = "上机日期"
                   DataGridView1.Columns(6).HeaderText = "下机时间"
                   DataGridView1.Columns(7).HeaderText = "下机日期"
                End If
            End If
        End If
    End Sub
 
    ''' <summary>
    ''' 模板方法，定义虚函数ToEnglish，查询字段转化为数据库字段
    ''' </summary>
    ''' <paramname="cboName"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Overridable FunctionToEnglish(cboName As String) As String
        Return ""
    End Function
 
    ''' <summary>
    '''模版方法，获得数据库表名
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Overridable Function GetdbName() AsString
        Return ""
    End Function
 
    ''' <summary>
    ''' 第一个组合关系不为空
    ''' </summary>
    ''' <paramname="sender"></param>
    ''' <paramname="e"></param>
    ''' <remarks></remarks>
    Protected SubcboRelation1_SelectedIndexChanged(sender As Object, e As EventArgs) HandlescboRelation1.SelectedIndexChanged
        If cboRelation1.Text = ""Then
            cboField2.Enabled = False
            cboField3.Enabled = False
            cboOperator2.Enabled = False
            cboOperator3.Enabled = False
 
            cboRelation2.Enabled = False
            txtContent2.Enabled = False
            txtContent3.Enabled = False
        Else
            cboField2.Enabled = True
            cboOperator2.Enabled = True
            txtContent2.Enabled = True
 
            cboRelation2.Enabled = True
        End If
 
    End Sub
 
 
    ''' <summary>
    ''' 第二个组合关系不为空
    ''' </summary>
    ''' <paramname="sender"></param>
    ''' <paramname="e"></param>
    ''' <remarks></remarks>
    Protected SubcboRelation2_SelectedIndexChanged(sender As Object, e As EventArgs) HandlescboRelation2.SelectedIndexChanged
        If cboRelation2.Text = ""Then
            cboField3.Enabled = False
            cboOperator3.Enabled = False
            txtContent3.Enabled = False
        Else
            cboField3.Enabled = True
            cboOperator3.Enabled = True
            txtContent3.Enabled = True
        End If
    End Sub
    ''' <summary>
    ''' 导出到excel
    ''' </summary>
    ''' <paramname="sender"></param>
    ''' <paramname="e"></param>
    ''' <remarks></remarks>
    Public Overridable SubbtnExport_Click(sender As Object, e As EventArgs) Handles btnExport.Click
        '打开Excel的应用程序 
        Dim ExcelADD As New Excel.Application()
 
        '添加一个工作本 
        Dim ExcelWordBook As Excel.Workbook =ExcelADD.Workbooks.Add()
 
        '添加一个表 
        Dim ExcelWorkSheet As Excel.Worksheet =ExcelWordBook.Sheets("sheet1")
 
        '显示Excel 
        ExcelADD.Visible = True
 
        '用于将DataGridView中的表赋值到Excel中的表中 
        Dim i As Integer
        Dim j As Integer
 
        '将DataGridView中的字段名赋值给Excel表中的第一行 
        Dim Cols As Integer
        For Cols = 1 ToDataGridView1.Columns.Count
            ExcelWorkSheet.Cells(1, Cols) =DataGridView1.Columns(Cols - 1).HeaderText
        Next
 
        '将DataGridView表格中的内容导入到Excel表中 
        For i = 0 To DataGridView1.RowCount - 1
            'DataGrideView中的表头行不作为行数来计算 
            For j = 0 ToDataGridView1.ColumnCount - 1
                'Excel的第一行是标题，所以应从第二行开始，i+2注意DataGridView的坐标是先列后行 
                ExcelWorkSheet.Cells(i + 2, j +1) = DataGridView1(j, i).Value.ToString()
            Next
        Next
    End Sub
    ''' <summary>
    ''' 清除窗体内容
    ''' </summary>
    ''' <paramname="sender"></param>
    ''' <paramname="e"></param>
    ''' <remarks></remarks>
    Public Overridable SubbtnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
        Call ClearAll(Me)
        DataGridView1.DataSource = Nothing
    End Sub
End Class

B层代码传递

 

Public ClassComboQueryBLL
    ''' <summary>
    ''' 传递组合查询的条件
    ''' </summary>
    ''' <paramname="encboquery"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Function ComboQuery(ByVal encboqueryAs Entity.ComboQueryEntity) As Entity.MyQueryEntity
        Dim DataAccess As New DAL.DataAccess
        Dim IComboQuery As IDAL.IComboQuery
        '定义一个接口变量
 
        IComboQuery =DataAccess.CreateComboQuery
        '得到实际的数据库访问实例
 
        Dim encbo =IComboQuery.ComboQuery(encboquery)
 
        If encbo Is Nothing Then
            Return Nothing
        Else
            Return encbo
        End If
    End Function
End Class

D层完成与数据库的交互，以及将datatable转化为泛型

 

ImportsSystem.Data.SqlClient
Imports IDAL
Imports Entity
 
Public ClassComboQueryDAL : Implements IDAL.IComboQuery
    ''' <summary>
    ''' 组合查询
    ''' </summary>
    ''' <paramname="encboquery">要查询的实体</param>
    ''' <returns>信息表</returns>
    ''' <remarks></remarks>
    Public Function ComboQuery(encboquery AsEntity.ComboQueryEntity) As MyQueryEntity ImplementsIDAL.IComboQuery.ComboQuery
        'Dim mylist As New List(OfEntity.ComboQueryEntity)
        Dim strSQL As String ="P_ComboQuery" '调用存储过程 
        '设置参数
        Dim prams As SqlParameter() = {NewSqlParameter("@cmbField1", encboquery.Field1),
                                    NewSqlParameter("@cmbField2", encboquery.Field2),
                                    NewSqlParameter("@cmbField3", encboquery.Field3),
                                    NewSqlParameter("@cmbOperation1", encboquery.Operator1),
                                    NewSqlParameter("@cmbOperation2", encboquery.Operator2),
                                    NewSqlParameter("@cmbOperation3", encboquery.Operator3),
                                    NewSqlParameter("@txtContent1", encboquery.Content1),
                                    NewSqlParameter("@txtContent2", encboquery.Content2),
                                    NewSqlParameter("@txtContent3", encboquery.Content3),
                                    NewSqlParameter("@cmbRelation1", encboquery.Relation1),
                                    NewSqlParameter("@cmbRelation2", encboquery.Relation2),
                                    NewSqlParameter("@dbName", encboquery.dbName)}
 
        Dim helper As New SqlHelper
        Dim dbcboquery =helper.ExecuteSelect(strSQL, CommandType.StoredProcedure, prams)
        'mylist = conEntity.convertToList(OfEntity.ComboQueryEntity)(dbcboquery)
        If encboquery.dbName ="Linelog" Then
            Return MyReturn2(dbcboquery)   '转换为实体类型
        Else
            If encboquery.dbName ="v_studentinfo" Then
                ReturnMyReturn3(dbcboquery)   '转换为实体类型
            Else
                ReturnMyReturn1(dbcboquery)   '转换为实体类型
            End If
        End If
    End Function
 
    ''' <summary>
    ''' 教师工作，选择返回的Datatable，转换成泛型集合
    ''' </summary>
    ''' <paramname="dt">组合查询，查询的信息</param>
    Public Function MyReturn1(dt As DataTable)As MyQueryEntity Implements IComboQuery.MyReturn1
        Dim mylist As List(OfEntity.WorklogEntity)
        mylist =Entity.conEntity.convertToList(Of Entity.WorklogEntity)(dt)
        Dim MyQueryList As New MyQueryEntity
        MyQueryList.WorklogEntity = mylist
        Return MyQueryList
    End Function
    ''' <summary>
    ''' 学生上机记录统计，选择返回的Datatable，转换成泛型集合
    ''' </summary>
    ''' <paramname="dt">组合查询，查询的信息</param>
    Public Function MyReturn2(dt As DataTable)As MyQueryEntity Implements IComboQuery.MyReturn2
        Dim mylist As List(OfEntity.LinelogEntity)
        mylist =Entity.conEntity.convertToList(Of Entity.LinelogEntity)(dt)
        Dim MyQueryList As New MyQueryEntity
        MyQueryList.LineEntity = mylist
        Return MyQueryList
    End Function
    ''' <summary>
    ''' 学生基本信息维护，选择返回的Datatable，转换成泛型集合
    ''' </summary>
    ''' <paramname="dt">组合查询，查询的信息</param>
    Public Function MyReturn3(dt As DataTable)As MyQueryEntity Implements IComboQuery.MyReturn3
        Dim mylist As List(OfEntity.RegisterEntity)
        mylist =Entity.conEntity.convertToList(Of Entity.RegisterEntity)(dt)
        Dim MyQueryList As New MyQueryEntity
        MyQueryList.RegisterEntity = mylist
        Return MyQueryList
    End Function
End Class

数据库存储过程

 

USE [MyDB]
GO
/****** Object:  StoredProcedure [dbo].[p_ComboQuery]    Script Date: 02/15/2015 21:12:33 ******/
SET ANSI_NULLS ON
GO
SETQUOTED_IDENTIFIER ON
GO
ALTER proc[dbo].[p_ComboQuery]
    @cmbField1 varchar(10), 
    @cmbOperation1 varchar(10), 
    @txtContent1 varchar(10), 
    @cmbField2 varchar(10), 
    @cmbOperation2 varchar(10), 
    @txtContent2 varchar(10), 
    @cmbField3 varchar(10), 
    @cmbOperation3 varchar(10), 
    @txtContent3 varchar(10), 
    @cmbRelation1 varchar(10), 
    @cmbRelation2 varchar(10), 
    @dbName varchar(20) 
AS 
    declare @TempSqlvarchar(500)--临时存放sql语句   
BEGIN 
    SET @TempSql='SELECT * FROM '+@dbName +'WHERE ' +@cmbField1 +@cmbOperation1+char(39) + @txtContent1 + char(39)   
    if @cmbRelation1 != '' 
    BEGIN   
        SET@TempSql=@TempSql+@cmbRelation1+CHAR(32)+@cmbField2+@cmbOperation2+CHAR(39)+@txtContent2+CHAR(39)   
        if @cmbRelation2!= '' 
        BEGIN   
        SET@TempSql=@TempSql+@cmbRelation2+CHAR(32)+@cmbField3+@cmbOperation3+CHAR(39)+@txtContent3+CHAR(39)   
        END   
    END   
EXECUTE(@TempSql) 
end

         模板的好处就是在于只是父窗体去走大的框架，子窗体去特殊的实现，其实子窗体只需要完成U层的一些补充即可，下面以一个子窗体的U层代码举例

 

Public ClassfrmSaveStudentUI
 Private Sub frmSaveStudentUI_Load(sender AsObject, e As EventArgs) Handles MyBase.Load
        cboField1.Items.Add("学号")
        cboField1.Items.Add("卡号")
        cboField1.Items.Add("姓名")
        cboField1.Items.Add("性别")
        cboField1.Items.Add("年级")
        cboField1.Items.Add("班级")
        cboField1.Items.Add("专业")
 
        cboField2.Items.Add("学号")
        cboField2.Items.Add("卡号")
        cboField2.Items.Add("姓名")
        cboField2.Items.Add("性别")
        cboField2.Items.Add("年级")
        cboField2.Items.Add("班级")
        cboField2.Items.Add("专业")
 
        cboField3.Items.Add("学号")
        cboField3.Items.Add("卡号")
        cboField3.Items.Add("姓名")
        cboField3.Items.Add("性别")
        cboField3.Items.Add("年级")
        cboField3.Items.Add("班级")
        cboField3.Items.Add("专业")
    End Sub
 
    ''' <summary> 
    ''' 把加载的汉字转换成数据库的字段 
    ''' </summary> 
    ''' <param name="cbofield"></param> 
    ''' <returns></returns> 
    ''' <remarks></remarks> 
    Public Overrides FunctionToEnglish(cbofield As String) As String
        Select Case cbofield
            Case "学号"
                ToEnglish ="studentno"
            Case "卡号"
                ToEnglish = "cardno"
            Case "姓名"
                ToEnglish = "sname"
            Case "性别"
                ToEnglish = "Sex"
            Case "年级"
                ToEnglish = "Grade"
            Case "班级"
                ToEnglish = "Class"
            Case "专业"
                ToEnglish ="Department"
            Case "与"
                ToEnglish = "and"
            Case "或"
                ToEnglish = "or"
            Case Else
                ToEnglish = ""
        End Select
    End Function
 
    '重写获得表名方法 
    Public Overrides Function GetdbName() AsString
        Return "v_studentinfo"
    End Function
End Class

        只要完成了窗体继承，这些都很方便，真正做到了以一比三，何乐而不为呢？但是组合查询这里大家要注意的是转化为泛型的时候会遇到一些问题，以往的转化都是在D层调用一个函数就好了，但是这次不太一样，我们会发现转化完之后显示出来的是字段。原因就是我们的datatable中字段和实体字段不相符，解决方法就是在组合窗体实体中引入继承窗体的实体。就是我父窗体U层中引入的MyQueryEntity实体，D层的三个特殊函数。下面是我MyQueryEntity代码：


 Public ClassMyQueryEntity
    '转化为LinelogEntity
    Private strLinelogEntity As List(OfLinelogEntity)
    Public Property LineEntity() As List(OfLinelogEntity)
        Get
            Return strLinelogEntity
        End Get
        Set(ByVal value As List(OfLinelogEntity))
            strLinelogEntity = value
        End Set
    End Property
    '转化为RegisterEntity
    Private strRegisterEntity As List(OfRegisterEntity)
    Public Property RegisterEntity() As List(OfRegisterEntity)
        Get
            Return strRegisterEntity
        End Get
        Set(ByVal value As List(OfRegisterEntity))
            strRegisterEntity = value
        End Set
    End Property
    '转化为WorklogEntity
    Private strWorklogEntity As List(OfWorklogEntity)
    Public Property WorklogEntity() As List(OfWorklogEntity)
        Get
            Return strWorklogEntity
        End Get
        Set(ByVal value As List(OfWorklogEntity))
            strWorklogEntity = value
        End Set
    End Property
End Class

         师傅说以后我们都会用到转化泛型，泛型的好处很多，以后我们会慢慢的体会到，现在的公司也严格要求用泛型，以后就是泛型的天下了，现在我们就遇到问题解决问题，以后的工作就会轻松很多啊！


重构—组合查询

标签：窗体继承   模板方法组合查询   datatable转化为泛型   

原文地址：http://blog.csdn.net/xfz0330/article/details/43850609
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