Update 和 CancelUpdate 方法示例 (VB)

此示例演示将 Update 方法与 CancelUpdate 方法结合使用。

'BeginUpdateVB  
Public Sub Main()  
    On Error GoTo ErrorHandler  
  
    'To integrate this code  
    'replace the data source and initial catalog values  
    'in the connection string  
  
    ' recordset and connection variables  
    Dim rstEmployees As ADODB.Recordset  
    Dim Cnxn As ADODB.Connection  
    Dim strCnxn As String  
    Dim strSQLEmployees As String  
     ' buffer variables  
    Dim strOldFirst As String  
    Dim strOldLast As String  
    Dim strMessage As String  
  
    ' Open connection  
    Set Cnxn = New ADODB.Connection  
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _  
        "Initial Catalog='Pubs';Integrated Security='SSPI';"  
    Cnxn.Open strCnxn  
  
    ' Open recordset to enable changes  
    Set rstEmployees = New ADODB.Recordset  
    strSQLEmployees = "SELECT fname, lname FROM Employee ORDER BY lname"  
    rstEmployees.Open strSQLEmployees, Cnxn, adOpenKeyset, adLockOptimistic, adCmdText  
  
    ' Store original data  
    strOldFirst = rstEmployees!fname  
    strOldLast = rstEmployees!lname  
    ' Change data in edit buffer  
    rstEmployees!fname = "Linda"  
    rstEmployees!lname = "Kobara"  
  
    ' Show contents of buffer and get user input  
    strMessage = "Edit in progress:" & vbCr & _  
        "  Original data = " & strOldFirst & " " & _  
        strOldLast & vbCr & "  Data in buffer = " & _  
        rstEmployees!fname & " " & rstEmployees!lname & vbCr & vbCr & _  
        "Use Update to replace the original data with " & _  
        "the buffered data in the Recordset?"  
  
    If MsgBox(strMessage, vbYesNo) = vbYes Then  
        rstEmployees.Update  
    Else  
        rstEmployees.CancelUpdate  
    End If  
  
    ' show the resulting data  
    MsgBox "Data in recordset = " & rstEmployees!fname & " " & _  
       rstEmployees!lname  
  
    ' restore original data because this is a demonstration  
    If Not (strOldFirst = rstEmployees!fname And _  
           strOldLast = rstEmployees!lname) Then  
        rstEmployees!fname = strOldFirst  
        rstEmployees!lname = strOldLast  
        rstEmployees.Update  
    End If  
  
    ' clean up  
    rstEmployees.Close  
    Cnxn.Close  
    Set rstEmployees = Nothing  
    Set Cnxn = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not rstEmployees Is Nothing Then  
        If rstEmployees.State = adStateOpen Then rstEmployees.Close  
    End If  
    Set rstEmployees = Nothing  
  
    If Not Cnxn Is Nothing Then  
        If Cnxn.State = adStateOpen Then Cnxn.Close  
    End If  
    Set Cnxn = Nothing  
  
    If Err <> 0 Then  
        MsgBox Err.Source & "-->" & Err.Description, , "Error"  
    End If  
End Sub  
' EndUpdateVB  

此示例演示将 Update 方法与 AddNew 方法结合使用。

Attribute VB_Name = "Update"  

另请参阅

CancelUpdate 方法 (ADO)
记录集对象 (ADO)
Update 方法