機房收費系統之學生信息基本維護

該來的總會來的！！！！組合查詢就這麼悄無聲息的到了，

組合查詢 最重要的就是運用數據的概念：

   Dim i As integer
    For i = 0 To 2
        With Combo1(i)
          	  .AddItem "卡號"
          	  .AddItem "學號"
          	  .AddItem "姓名"
          	 	 .AddItem "性別"
          	  .AddItem "日期"
           	 .AddItem "時間"
          	  .AddItem "機器名"
        End With
    Next i

還要注意一些細節問題：

Dim i As Integer
    i = Index
  If Combo1(i).Text = "姓名" Or Combo1(i).Text = "性別" Then  '防止出現姓名 備註等大於小於的情況
        Combo2(i).Clear
        Combo2(i).AddItem "="
        Combo2(i).AddItem "<>"
        Else
      Combo2(i).Clear      '每次切換完都要清空一下 防止重複疊加選項的情況出現
         Combo2(i).AddItem "="
         Combo2(i).AddItem "<"
         Combo2(i).AddItem ">"
         Combo2(i).AddItem "<>"
 End If

不要忘記日期控件：

For i = 0 To 2
If Combo1(i).Text = "日期" Then
            DTPicker1(i).Format = dtpShortDate
            DTPicker1(i).Visible = True
            Text1(i).Visible = False
        Else
    If Combo1(i).Text = "時間" Then
            DTPicker1(i).Format = dtpTime
            DTPicker1(i).Visible = True
            Text1(i).Visible = False
        Else
            DTPicker1(i).Visible = False
            Text1(i).Visible = True
        If Combo1(i).Text = "卡號" Or Combo1(i).Text = "學號" Or Combo1(i).Text = "姓名" Or Combo1(i).Text = "機器名" Or Combo1(i).Text = "性別" Then
            DTPicker1(i).Visible = False
            Text1(i).Visible = True
        End If
  End If
End If
  Next i

  '這裏日期是有多種格式的 dtpicker的fromat屬性提供了好幾種日期格式
  'format=0-dtpLongDate：格式是2018年12月13日
  'format=1-dtpShortDate：格式是2018/12/13
  'format=2-dtpTime：格式是0:00:00，這個時候是時間，不是日期
  'Format=3-dtpCustom，這個時候可以自定義格式，比如 
    dtpicker1.CustomFormat=Format("yy MM dd")

窗體準備完畢剩下的就是查詢了

 	Dim txtSQLlin As String
    Dim MsgText As String
    Dim Mrclin As ADODB.Recordset
    Dim i As Integer
        
        For i = 0 To 2
            If DTPicker1(i).Visible = True Then  '查詢的時候將dipicker中的日期賦值給文本框   將條件字段名轉換成相對應的數據庫字段名字符
                Text1(i).Text = DTPicker1(i).Value
            End If
        Next i
   
    If Not Testtxt(Combo1(0).Text) Or Not Testtxt(Combo4(0).Text) Or Not Testtxt(Text1(0).Text) Then
        MsgBox "請輸入第一行查詢條件的內容", 48, "提示"
        Combo1(0).SetFocus
        Exit Sub
    End If
    
    txtSQLlin = "select * from line_info where "
    txtSQLlin = txtSQLlin & Trim(Fieldname(Combo1(0).Text)) & Trim(Combo4(0).Text) & "'" & Trim(Text1(0).Text) & "'"
    
    If Not Combo7(0).Text = "" Then  '如果選擇框不是空值
    
    '判斷第二行是否輸入
    If Not Testtxt(Combo1(1).Text) Or Not Testtxt(Combo4(1).Text) Or Not Testtxt(Text1(1).Text) Then
        MsgBox "請輸入第二行條件內容", 48, "提示"
        Combo1(1).SetFocus
        Exit Sub
    End If
            
             txtSQLlin = txtSQLlin & " " & RelationName(Trim(Combo7(0).Text)) & " " & Fieldname(Combo1(1).Text) & " " & Trim(Combo4(1).Text) & "'" & Trim(Text1(1).Text) & " '"
                 
                 End If
    If Not Combo7(1).Text = "" Then
    '判斷第三行是否輸入
        If Not Testtxt(Combo1(2).Text) Or Not Testtxt(Combo4(2).Text) Or Not Testtxt(Text1(2).Text) Then
            MsgBox "請輸入第三行查詢條件的內容", 48, "提示"
            Combo1(2).SetFocus
            Exit Sub
        Else
                
            txtSQLlin = txtSQLlin & RelationName(Trim(Combo7(1).Text)) & " " & Fieldname(Combo1(2).Text) & Trim(Combo4(2).Text) & "'" & Trim(Text1(2).Text) & "'"
         '        Txtsql = Txtsql & RelationName(Combo3(1).Text) & " " & Fieldname(Combo1(2).Text) & Combo2(2).Text & "'" & Trim(Text1(2).Text) & "'"

        End If
    End If
    
    Set Mrclin = ExecuteSQL(txtSQLlin, MsgText)
    With MSFlexGrid1
                    .Rows = 1  '內容在當前單元格的水平和垂直居中對齊
                    .CellAlignment = 4  '內容在當前列居中對齊
                    .CellAlignment = 4
                    .TextMatrix(0, 0) = "卡號"
                    .TextMatrix(0, 1) = "姓名"
                    .TextMatrix(0, 2) = "上機日期"
                    .TextMatrix(0, 3) = "上機時間"
                    .TextMatrix(0, 4) = "下機日期"
                    .TextMatrix(0, 5) = "下機時間"
                    .TextMatrix(0, 6) = "消費金額"
                    .TextMatrix(0, 7) = "餘額"
                    .TextMatrix(0, 8) = "備註"
                    Do While Not Mrclin.EOF
                                        .Rows = .Rows + 1
                                        .CellAlignment = 4
                                        .CellAlignment = 4
                                        .TextMatrix(.Rows - 1, 0) = Trim(Mrclin.Fields(1))
                                        .TextMatrix(.Rows - 1, 1) = Trim(Mrclin.Fields(3))
                                        .TextMatrix(.Rows - 1, 2) = Trim(Mrclin.Fields(6))
                                        .TextMatrix(.Rows - 1, 3) = Trim(Mrclin.Fields(7))
                                        .TextMatrix(.Rows - 1, 4) = Trim(Mrclin.Fields(8)) & ""
                                        .TextMatrix(.Rows - 1, 5) = Trim(Mrclin.Fields(9)) & ""
                                        .TextMatrix(.Rows - 1, 6) = Trim(Mrclin.Fields(11))
                                        .TextMatrix(.Rows - 1, 7) = Trim(Mrclin.Fields(12))
                                        .TextMatrix(.Rows - 1, 8) = Trim(Mrclin.Fields(13))                 
                    Mrclin.MoveNext
                Loop
                Call AdjustColWidth(cmdinquir, MSFlexGrid1)
                   End With
                   If Mrclin.RecordCount = 0 Then
                   MsgBox "沒有您要查詢的信息", 48, "提示"
                   Combo1(0).SetFocus                  
                End If
           Mrclin.Close  
End Sub

這個組合查詢要好好理解一些 寫的時候一定要細心 遇到錯誤 多用斷點 監事窗口 立即窗口等工具檢查問題所在，然後一個會了 其他的就沒什麼問題的