Refresh 方法範例 (VB)

此範例示範如何使用 Refresh 方法，來重新整理預存程式 Command 物件的 Parameters 集合。

'BeginRefreshVB  
Public Sub Main()  
    On Error GoTo ErrorHandler  
  
    'To integrate this code  
    'replace the data source and initial catalog values  
    'in the connection strings  
  
    ' connection and recordset variables  
    Dim Cnxn As ADODB.Connection  
    Dim cmdByRoyalty As ADODB.Command  
    Dim rstByRoyalty As ADODB.Recordset  
    Dim rstAuthors As ADODB.Recordset  
    Dim strCnxn As String  
    Dim strSQLAuthors As String  
     ' record variables  
    Dim intRoyalty As Integer  
    Dim strAuthorID As String  
    Dim strRoyalty 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 a command object for a stored procedure  
    ' with one parameter  
    Set cmdByRoyalty = New ADODB.Command  
    Set cmdByRoyalty.ActiveConnection = Cnxn  
    cmdByRoyalty.CommandText = "byroyalty"  
    cmdByRoyalty.CommandType = adCmdStoredProc  
    cmdByRoyalty.Parameters.Refresh  
  
    ' Get parameter value, execute the command  
    ' and store the results in a recordset  
    strRoyalty = InputBox("Enter royalty:")  
    If strRoyalty = "" Then  
        Err.Raise 1, , "You either didn't enter royalty or canceled the input box. Exit the application"  
    End If  
  
    intRoyalty = Trim(strRoyalty)  
    cmdByRoyalty.Parameters(1) = intRoyalty  
    Set rstByRoyalty = cmdByRoyalty.Execute()  
  
    ' Open the Authors table to get author names for display  
    Set rstAuthors = New ADODB.Recordset  
    strSQLAuthors = "Authors"  
    rstAuthors.Open strSQLAuthors, Cnxn, adOpenForwardOnly, adLockPessimistic, adCmdTable  
  
    ' Print current data in the recordset  
    ' and add author names  
    Debug.Print "Authors with " & intRoyalty & " percent royalty"  
  
    Do Until rstByRoyalty.EOF  
        strAuthorID = rstByRoyalty!au_id  
        Debug.Print "   " & rstByRoyalty!au_id & ", ";  
        rstAuthors.Filter = "au_id = '" & strAuthorID & "'"  
        Debug.Print rstAuthors!au_fname & " "; rstAuthors!au_lname  
        rstByRoyalty.MoveNext  
    Loop  
  
    ' clean up  
    rstByRoyalty.Close  
    rstAuthors.Close  
    Cnxn.Close  
    Set rstByRoyalty = Nothing  
    Set rstAuthors = Nothing  
    Set Cnxn = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not rstByRoyalty Is Nothing Then  
        If rstByRoyalty.State = adStateOpen Then rstByRoyalty.Close  
    End If  
    Set rstByRoyalty = Nothing  
  
    If Not rstAuthors Is Nothing Then  
        If rstAuthors.State = adStateOpen Then rstAuthors.Close  
    End If  
    Set rstAuthors = 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  
'EndRefreshVB  

另請參閱

Command 物件 (ADO)
Parameters 集合 (ADO)
Refresh 方法 (ADO)