ActiveCommand 屬性範例 (VB)

此範例示範 ActiveCommand 屬性。

子常式會收到 Recordset 物件，該物件的 ActiveCommand 屬性用來顯示建立 Recordset 的命令文字和參數。

'BeginActiveCommandVB  
  
    'To integrate this code  
    'replace the data source and initial catalog values  
    'in the connection string  
  
Public Sub Main()  
    On Error GoTo ErrorHandler  
  
        'recordset and connection variables  
    Dim cmd As ADODB.Command  
    Dim rst As ADODB.Recordset  
    Dim Cnxn As ADODB.Connection  
    Dim strCnxn As String  
        'record variables  
    Dim strPrompt As String  
    Dim strName As String  
  
    Set Cnxn = New ADODB.Connection  
    Set cmd = New ADODB.Command  
  
    strPrompt = "Enter an author's name (e.g., Ringer): "  
    strName = Trim(InputBox(strPrompt, "ActiveCommandX Example"))  
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _  
        "Initial Catalog='Pubs';Integrated Security='SSPI';"  
  
        'create SQL command string  
    cmd.CommandText = "SELECT * FROM Authors WHERE au_lname = ?"  
    cmd.Parameters.Append cmd.CreateParameter("LastName", adChar, adParamInput, 20, strName)  
  
    Cnxn.Open strCnxn  
    cmd.ActiveConnection = Cnxn  
  
        'create the recordset by executing command string  
    Set rst = cmd.Execute(, , adCmdText)  
        'see the results  
    Call ActiveCommandXprint(rst)  
  
    ' clean up  
    Cnxn.Close  
    Set rst = Nothing  
    Set Cnxn = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not rst Is Nothing Then  
        If rst.State = adStateOpen Then rst.Close  
    End If  
    Set rst = 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  
'EndActiveCommandVB  

ActiveCommandXprint 常式只提供 Recordset 物件，但必須列印建立 Recordset 的命令文字和參數。 這可以完成，因為 Recordset 物件的 ActiveCommand 屬性會產生相關聯的 Command 物件。

Command 物件的 CommandText 屬性會產生建立 Recordset 的參數化命令。 Command 物件的 Parameters 集合會產生取代命令參數預留位置的值 (「?」)。

最後，會列印錯誤訊息或作者的名稱和識別碼。

'BeginActiveCommandPrintVB  
Public Sub ActiveCommandXprint(rstp As ADODB.Recordset)  
  
    Dim strName As String  
  
    strName = rstp.ActiveCommand.Parameters.Item("LastName").Value  
  
    Debug.Print "Command text = '"; rstp.ActiveCommand.CommandText; "'"  
    Debug.Print "Parameter = '"; strName; "'"  
  
    If rstp.BOF = True Then  
       Debug.Print "Name = '"; strName; "', not found."  
    Else  
       Debug.Print "Name = '"; rstp!au_fname; " "; rstp!au_lname; _  
             "', author ID = '"; rstp!au_id; "'"  
    End If  
  
    rstp.Close  
    Set rstp = Nothing  
End Sub  
'EndActiveCommandPrintVB  

另請參閱

ActiveCommand 屬性 (ADO)
Command 物件 (ADO)
Recordset 物件 (ADO)