frmsubjects.frm

学生选课系统

Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
'当前操作的记录集
Dim WithEvents adoprimaryrs As Recordset
Attribute adoprimaryrs.VB_VarHelpID = -1
Dim mbChangedByCode As Boolean
'BookMark标记
Dim mvBookMark As Variant
'是否处在编辑状态
Dim mbEditFlag As Boolean
'是否处在新增记录状态
Dim mbAddNewFlag As Boolean
'当前数据是否被改变
Dim mbDataChanged As Boolean

Private Sub cmdSearch_Click()
    txtSearch = UCase(Trim(txtSearch))
    adoprimaryrs.MoveFirst
    adoprimaryrs.Find (comSearch.Text & "='" & txtSearch & "'")
    If adoprimaryrs.AbsolutePosition < 0 Then
        MsgBox comSearch & " 没找到!!!", vbInformation, "注意"
        adoprimaryrs.MoveFirst
    End If
End Sub

Private Sub Form_Load()
    Dim db As Connection
    Set db = New Connection
    db.CursorLocation = adUseClient
    db.Open strConnection

    Set adoprimaryrs = New Recordset
    adoprimaryrs.Open "select Subject,NoOfBooks,IssueDays," & _
                        "FineCharge,ReserveCharge from Subjects", _
                        db, adOpenStatic, adLockOptimistic

    Dim oText As TextBox
    
    '动态绑定所有TextBox到数据源
    For Each oText In Me.txtFields
        Set oText.DataSource = adoprimaryrs
    Next
    mbDataChanged = False
    
    '指定搜索字段
    comSearch.AddItem ("Subject")
    comSearch.ListIndex = 0
End Sub

Private Sub Form_Unload(Cancel As Integer)
    Screen.MousePointer = vbDefault
End Sub

Private Sub adoPrimaryRS_MoveComplete(ByVal adReason As ADODB.EventReasonEnum, _
                                        ByVal pError As ADODB.Error, _
                                        adStatus As ADODB.EventStatusEnum, _
                                        ByVal pRecordset As ADODB.Recordset)
    '显示当前记录的位置
    lblStatus.Caption = "记录: " & CStr(adoprimaryrs.AbsolutePosition)
End Sub

Private Sub adoPrimaryRS_WillChangeRecord(ByVal adReason As ADODB.EventReasonEnum, ByVal cRecords As Long, adStatus As ADODB.EventStatusEnum, ByVal pRecordset As ADODB.Recordset)
    '这里是放置验证代码的地方
    '下面这些事件激发此事件发生
    Dim bCancel As Boolean
    
    Select Case adReason
        Case adRsnAddNew
        Case adRsnClose
        Case adRsnDelete
        Case adRsnFirstChange
        Case adRsnMove
        Case adRsnRequery
        Case adRsnResynch
        Case adRsnUndoAddNew
        Case adRsnUndoDelete
        Case adRsnUndoUpdate
        Case adRsnUpdate
    End Select
    
    If bCancel Then adStatus = adStatusCancel
End Sub

'"添加"按钮单击事件响应代码
Private Sub cmdAdd_Click()
    On Error GoTo AddErr
    With adoprimaryrs
        If Not (.BOF And .EOF) Then
            mvBookMark = .Bookmark
        End If
        .AddNew
        lblStatus.Caption = "添加记录"
        mbAddNewFlag = True
        SetButtons False
    End With

    Exit Sub
AddErr:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'"删除"按钮单击事件响应代码
Private Sub cmdDelete_Click()
    On Error GoTo DeleteErr
    With adoprimaryrs
        .Delete
        .MoveNext
        If .EOF Then .MoveLast
    End With
    Exit Sub
DeleteErr:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'"刷新"按钮单击事件响应代码
Private Sub cmdRefresh_Click()
    '多用户情况下才需要使用
    On Error GoTo RefreshErr
    adoprimaryrs.Requery
    Exit Sub
RefreshErr:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'"编辑"按钮单击事件响应代码
Private Sub cmdEdit_Click()
    On Error GoTo EditErr

    lblStatus.Caption = "编辑记录"
    mbEditFlag = True
    SetButtons False
    Exit Sub

EditErr:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'"取消"按钮单击事件响应代码
Private Sub cmdCancel_Click()
    On Error Resume Next

    SetButtons True
    mbEditFlag = False
    mbAddNewFlag = False
    adoprimaryrs.CancelUpdate
    If mvBookMark > 0 Then
        adoprimaryrs.Bookmark = mvBookMark
    Else
        adoprimaryrs.MoveFirst
    End If
    mbDataChanged = False

End Sub

'"更新"按钮单击事件响应代码
Private Sub cmdUpdate_Click()
    On Error GoTo UpdateErr

    adoprimaryrs.UpdateBatch adAffectAll

    If mbAddNewFlag Then
        '移动到新记录
        adoprimaryrs.MoveLast
    End If

    mbEditFlag = False
    mbAddNewFlag = False
    SetButtons True
    mbDataChanged = False

    Exit Sub
UpdateErr:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

Private Sub cmdClose_Click()
    Unload Me
End Sub

'"移动到首记录"按钮单击事件响应代码
Private Sub cmdFirst_Click()
    On Error GoTo GoFirstError
    adoprimaryrs.CancelUpdate
    adoprimaryrs.MoveFirst
    mbDataChanged = False
    Exit Sub

GoFirstError:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'"移动到尾记录"按钮单击事件响应代码
Private Sub cmdLast_Click()
    On Error GoTo GoLastError
    adoprimaryrs.CancelUpdate
    adoprimaryrs.MoveLast
    mbDataChanged = False
    Exit Sub

GoLastError:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'"移动到下一条记录"按钮单击事件响应代码
Private Sub cmdNext_Click()
    On Error GoTo GoNextError
    adoprimaryrs.CancelUpdate
    If Not adoprimaryrs.EOF Then adoprimaryrs.MoveNext
    If adoprimaryrs.EOF And adoprimaryrs.RecordCount > 0 Then
        Beep
        '超出记录尾，需要恢复
        adoprimaryrs.MoveLast
    End If
    '显示当前记录
    mbDataChanged = False
    Exit Sub

GoNextError:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

'移动到上一条记录"按钮单击事件响应代码
Private Sub cmdPrevious_Click()
    On Error GoTo GoPrevError
    adoprimaryrs.CancelUpdate
    If Not adoprimaryrs.BOF Then adoprimaryrs.MovePrevious
    If adoprimaryrs.BOF And adoprimaryrs.RecordCount > 0 Then
        Beep
        '超出记录头，需要恢复
        adoprimaryrs.MoveFirst
    End If
    '显示当前记录
    mbDataChanged = False
    Exit Sub

GoPrevError:
    MsgBox "发生错误：" & Err.Description, vbExclamation, "错误"
End Sub

Private Sub SetButtons(bVal As Boolean)
    cmdAdd.Visible = bVal
    cmdEdit.Visible = bVal
    cmdUpdate.Visible = Not bVal
    cmdCancel.Visible = Not bVal
    cmdDelete.Visible = bVal
    cmdClose.Visible = bVal
    cmdRefresh.Visible = bVal
    cmdNext.Enabled = bVal
    cmdFirst.Enabled = bVal
    cmdLast.Enabled = bVal
    cmdPrevious.Enabled = bVal
    Frame1.Enabled = bVal
  
End Sub
Private Sub txtFields_LostFocus(Index As Integer)
    '移除多余的空格
    txtFields(Index).Text = Trim(txtFields(Index).Text)

    If Index = 0 Then
        txtFields(Index).Text = UCase(txtFields(Index).Text)
    Else
        If Not IsNumeric(txtFields(Index).Text) Then
            MsgBox "请输入数字!!!", vbInformation
            txtFields(Index).Text = ""
            txtFields(Index).SetFocus
        End If

    End If
End Sub