机房重构组合查询之模板模式
前言：
前人的经验让我们少走了很多的弯路。机房收费系统四大核心：组合查询，结账，上下机，报表。 从第一遍收费系统中我们就知道，很多窗体都一样，而且要实现的也是差不多的功能，所以在我们学了模板模式之后，组合查询这一方面的问题就可以得到很好的处理了。模板模式的使用大大的减少了我们的代码量。
内容：
model 层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;">Public Class InquireMotherModel
Private _cmbName1 As String 'd定义字段名
Private _cmbName2 As String
Private _cmbName3 As String
Private _cmbOper1 As String '定义操作符
Private _cmbOper2 As String
Private _cmbOper3 As String
Private _txtInquire1 As String
Private _txtInquire2 As String '定义查询内容
Private _txtInquire3 As String
Private _cmbShip1 As String
Private _cmbShip2 As String '定义组合关系
Private _cmbShip3 As String
Private _Dbname As String '定义 数据库名
Public Property Dbname As String
Get
Return _Dbname
End Get
Set(value As String)
_Dbname = value
End Set
End Property
Public Property cmbName1 As String
Get
Return _cmbName1
End Get
Set(value As String)
_cmbName1 = value
End Set
End Property
Public Property cmbName2 As String
Get
Return _cmbName2
End Get
Set(value As String)
_cmbName2 = value
End Set
End Property
Public Property cmbName3 As String
Get
Return _cmbName3
End Get
Set(value As String)
_cmbName3 = value
End Set
End Property
Public Property cmbOper1 As String
Get
Return _cmbOper1
End Get
Set(value As String)
_cmbOper1 = value
End Set
End Property
Public Property cmbOper2 As String
Get
Return _cmbOper2
End Get
Set(value As String)
_cmbOper2 = value
End Set
End Property
Public Property cmbOper3 As String
Get
Return _cmbOper3
End Get
Set(value As String)
_cmbOper3 = value
End Set
End Property
Public Property txtInquire1 As String
Get
Return _txtInquire1
End Get
Set(value As String)
_txtInquire1 = value
End Set
End Property
Public Property txtInquire2 As String
Get
Return _txtInquire2
End Get
Set(value As String)
_txtInquire2 = value
End Set
End Property
Public Property txtInquire3 As String
Get
Return _txtInquire3
End Get
Set(value As String)
_txtInquire3 = value
End Set
End Property
Public Property cmbShip1 As String
Get
Return _cmbShip1
End Get
Set(value As String)
_cmbShip1 = value
End Set
End Property
Public Property cmbShip2 As String
Get
Return _cmbShip2
End Get
Set(value As String)
_cmbShip2 = value
End Set
End Property
End Class
</span>
IDAL层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;">Imports Model
Public Interface IinquireMother
'增加查询的接口
Function CheckInquire(ByVal userinfo As Model.InquireMotherModel) As DataTable
End Interface</span>
Facatory 层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;"> '创建组合查询的接口
Public Function InquireMother() As IDAL.IinquireMother
Return CType(Assembly.Load("DAL").CreateInstance("DAL.InquireMotherDAL"), IDAL.IinquireMother)
End Function</span>
DAL层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;">Imports Model
Imports IDAL
Imports SQLHelper
Imports System.Data.SqlClient
Public Class InquireMotherDAL : Implements IDAL.IinquireMother
Dim shelper As New SQLHelper.SqlHelper
Public Function CheckInquire(userinfo As InquireMotherModel) As DataTable Implements IinquireMother.CheckInquire
Dim cmdText As String
Dim dt As DataTable
cmdText = "select * from " & userinfo.Dbname & " where "
'只有一个查询条件
If Trim(userinfo.cmbShip1) = "" Then
cmdText = cmdText & userinfo.cmbName1 & userinfo.cmbOper1 & "'" & userinfo.txtInquire1 & "'"
Else
'有两组查询条件
If Trim(userinfo.cmbShip2) = "" Then
cmdText = cmdText & userinfo.cmbName1 & userinfo.cmbOper1 & "'" & userinfo.txtInquire1 & "'" & userinfo.cmbShip1 & " " & userinfo.cmbName2 & userinfo.cmbOper2 & "'" & userinfo.txtInquire2 & "'"
Else
cmdText = cmdText & userinfo.cmbName1 & userinfo.cmbOper1 & "'" & userinfo.txtInquire1 & userinfo.cmbShip1 & " " & userinfo.cmbName2 & userinfo.cmbOper2 & "'" & userinfo.txtInquire2 & "'" & userinfo.cmbShip2 & " " & userinfo.cmbName3 & userinfo.cmbOper3 & "'" & userinfo.txtInquire3 & "'"
End If
End If
dt = shelper.ExecSelect(cmdText, CommandType.Text)
Return dt
End Function
End Class
</span>
BLL层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;">Imports Model
Imports Factory
Imports IDAL
Public Class InquireMotherBLL
'查询
Public Function CheckInquireMother(ByVal userinfo As Model.InquireMotherModel) As DataTable
Dim fac As New Factory.FactoryDB
Dim icheck As IDAL.IinquireMother
Dim myList As DataTable
icheck = fac.InquireMother
myList = icheck.CheckInquire(userinfo)
Return myList
End Function
End Class
</span>
Facade层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;">Imports BLL
Imports Model
Public Class InquireMotherFacade
'查询
Function InquireMother(ByVal userinfo As Model.InquireMotherModel) As DataTable
Dim inquire1 As New BLL.InquireMotherBLL
Dim myList As DataTable
myList = inquire1.CheckInquireMother(userinfo)
Return myList
End Function
End Class
</span>
U层
<span style="font-family:KaiTi_GB2312;font-size:18px;color:#333333;">Imports Model
Imports Microsoft.Office.Interop.Excel
Imports Microsoft.Office.Interop
Imports System.Data
Imports System.IO
Imports System.Windows.Forms
Public Class frminquireMother
Protected InquireMother As New Model.InquireMotherModel
' 模板方法，定义函数ToEnglish，查询字段转化为数据库字段
Public Overridable Function GetEnglish(cmbName As String) As String
Return ""
End Function
'获取数据库表名
Protected Overridable Function GetdbName() As String
Return ""
End Function
'把表显示到datagridiew中
Protected Overridable Sub Todgv(ByVal inquireMother As InquireMotherModel)
End Sub
'拼接字符串
Public Function Query(frm As frminquireMother, ByVal inquireMother As InquireMotherModel) As String
Dim cmdText As String = "" & frm.GetEnglish(frm.cmbName1.Text) & frm.cmbOper1.Text & "" & inquireMother.txtInquire1 & "'"
'非组合查询
If frm.cmbShip1.Text = "" Then
cmdText = cmdText
Else
'关系1为空时，关系2不为空
If frm.cmbShip1.Text <> "" Then
cmdText = cmdText & frm.GetEnglish(frm.cmbShip1.Text) & "" &
frm.GetEnglish(frm.cmbName2.Text) & frm.cmbOper2.Text & "'" & frm.txtInquire2.Text & "'"
Else
'关系1关系2 都不为空
cmdText = cmdText & frm.GetEnglish(frm.cmbShip1.Text) & "" &
frm.GetEnglish(frm.cmbName2.Text) & frm.cmbOper2.Text & "'" & frm.txtInquire2.Text & "'" & "" &
frm.GetEnglish(frm.cmbShip2.Text) & "" &
frm.GetEnglish(frm.cmbName3.Text) & frm.cmbOper3.Text & "'" & frm.txtInquire3.Text & "'"
End If
End If
Return cmdText
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click '点击查询按钮
' Try
'判断组合框不为空
If cmbShip1.Text = "" Then
If Trim(cmbName1.Text) = "" Or Trim(cmbOper1.Text) = "" Or Trim(txtInquire1.Text) = "" Then
MsgBox("请完善第一行的查询条件", 0, "温馨提示")
Exit Sub
End If
End If
If cmbShip1.Text <> "" Then '如果组合关系不为空
If cmbName1.Text = "" Or cmbOper1.Text = "" Or txtInquire1.Text = "" Or cmbName2.Text = "" Or cmbOper2.Text = "" Or txtInquire2.Text = "" Then '那么第二行和第一行的所有都要填满 否则不能进行查询
MsgBox("请完善查询条件", 0, "温馨提示")
Exit Sub
End If
End If
If cmbShip2.Text <> "" Then '如果第二个组合关系部位空
If cmbName1.Text = "" Or cmbOper1.Text = "" Or txtInquire1.Text = "" Or cmbName2.Text = "" Or cmbOper2.Text = "" Or txtInquire2.Text = "" Or cmbName3.Text = "" Or cmbOper3.Text = "" Or txtInquire3.Text = "" Then '那么三个条件都得填满
MsgBox("所有查询条件不能为空，请完善查询条件", 0, "温馨提示")
Exit Sub
End If
End If
'将参数传给实体
InquireMother.Dbname = GetdbName() '获取数据库名称
InquireMother.cmbName1 = GetEnglish(cmbName1.Text)
InquireMother.cmbName2 = GetEnglish(cmbName2.Text)
InquireMother.cmbName3 = GetEnglish(cmbName3.Text)
InquireMother.cmbOper1 = cmbOper1.Text.Trim
InquireMother.cmbOper2 = cmbOper2.Text.Trim
InquireMother.cmbOper3 = cmbOper3.Text.Trim
'查询时非数字要加上‘’
If IsNumeric(txtInquire1.Text) Then
InquireMother.txtInquire1 = txtInquire1.Text.Trim
Else
InquireMother.txtInquire1 = "'" & txtInquire1.Text.Trim & "'"
End If
If IsNumeric(txtInquire2.Text) Then
InquireMother.txtInquire2 = txtInquire2.Text.Trim
Else
InquireMother.txtInquire2 = "'" & txtInquire2.Text.Trim & "'"
End If
If IsNumeric(txtInquire3.Text) Then
InquireMother.txtInquire3 = txtInquire3.Text.Trim
Else
InquireMother.txtInquire3 = "'" & txtInquire3.Text.Trim & "'"
End If
InquireMother.cmbShip1 = GetEnglish(cmbShip1.Text)
InquireMother.cmbShip2 = GetEnglish(cmbShip2.Text)
'查找记录
Dim dt As New Data.DataTable
Dim facadeGeneral As New Facade.InquireMotherFacade
dt = facadeGeneral.InquireMother(InquireMother)
If dt.Rows.Count = 0 Then
MsgBox("没有符合条件的记录", 0, "温馨提示")
Else
'把表显示到dgv中
Call Todgv(InquireMother)
End If
'Catch ex As Exception
' MsgBox(ex.Message)
' End Try
End Sub
Private Sub frminquireMother_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'将参数传递给实体，赋初值
'字段名
InquireMother.cmbName1 = ""
InquireMother.cmbName2 = ""
InquireMother.cmbName3 = ""
'操作符
cmbOper1.Items.Add(">")
cmbOper1.Items.Add("=")
cmbOper1.Items.Add("<")
cmbOper1.Items.Add("<>")
cmbOper2.Items.Add(">")
cmbOper2.Items.Add("=")
cmbOper2.Items.Add("<")
cmbOper2.Items.Add("<>")
cmbOper3.Items.Add(">")
cmbOper3.Items.Add("=")
cmbOper3.Items.Add("<")
cmbOper3.Items.Add("<>")
'关系
cmbShip1.Items.Add("与")
cmbShip2.Items.Add("或")
'窗体加载后第二行和第三行的查询不能用
cmbName2.Enabled = False
cmbName3.Enabled = False
cmbOper2.Enabled = False
cmbOper3.Enabled = False
cmbShip2.Enabled = False
txtInquire2.Enabled = False
txtInquire3.Enabled = False
'调整列宽为根据内容自动调节
Dim i As Integer
For i = 0 To dgvRecord.Columns.Count - 1
dgvRecord.Columns(i).Width = DataGridViewAutoSizeColumnMode.AllCells
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click '导出excel
'先添加引用才能用office
Dim myExcel As New Microsoft.Office.Interop.Excel.Application()
myExcel.Application.Workbooks.Add(True)
myExcel.Visible = True
'取出dgvRecord的编号列
Dim m As Integer
For m = 0 To dgvRecord.ColumnCount - 1
myExcel.Cells(1, m + 1) = Me.dgvRecord.Columns(m).HeaderText
Next m
'往Excel表里添加数据
Dim i As Integer
For i = 0 To dgvRecord.ColumnCount - 1
Dim j As Integer
For j = 0 To dgvRecord.ColumnCount - 1
If Me.dgvRecord(j, i).Value Is System.DBNull.Value Then
myExcel.Cells(i + 2, j + 1) = ""
Else
myExcel.Cells(i + 2, j + 1) = dgvRecord(j, i).Value.ToString
End If
Next j
Next i
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click '退出
Me.Close()
End Sub
End Class</span>
总结：
model是一个大的实体，里面包括了模板上所有控件的属性。按照七层的思想搭建一条线，作为模板模式的主线，而继承的子窗体重写主线上的一些方法就能实现模板模式的调用。这样只需要写一条线 就可以让很多的窗体都来调用。减少了代码的重复。提高了效率。