Item 屬性範例 (VB)

此範例示範 Item 屬性如何存取集合的成員。 此範例會使用參數化命令開啟 Pubs 資料庫的 Authors 資料表。

對資料庫發出的命令中的參數，是依據索引和名稱從 Command 物件的 Parameters 集合中存取的。 然後會依據索引和名稱，從該物件的 Fields 集合存取所傳回 Recordset 的欄位。

'BeginItemVB  
  
    'To integrate this code  
    'replace the data source and initial catalog values  
    'in the connection string  
  
Public Sub Main()  
    On Error GoTo ErrorHandler  
  
    Dim Cnxn As ADODB.Connection  
    Dim rstAuthors As ADODB.Recordset  
    Dim cmd As ADODB.Command  
    Dim prm As ADODB.Parameter  
    Dim fld As ADODB.Field  
    Dim strCnxn As String  
  
    Dim ix As Integer  
    Dim limit As Long  
    Dim Column(0 To 8) As Variant  
  
    Set Cnxn = New ADODB.Connection  
    Set rstAuthors = New ADODB.Recordset  
    Set cmd = New ADODB.Command  
  
    'Set the array with the Authors table field (column) names  
    Column(0) = "au_id"  
    Column(1) = "au_lname"  
    Column(2) = "au_fname"  
    Column(3) = "phone"  
    Column(4) = "address"  
    Column(5) = "city"  
    Column(6) = "state"  
    Column(7) = "zip"  
    Column(8) = "contract"  
  
    cmd.CommandText = "SELECT * FROM Authors WHERE state = ?"  
    Set prm = cmd.CreateParameter("ItemXparm", adChar, adParamInput, 2, "CA")  
    cmd.Parameters.Append prm  
     ' set connection  
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _  
        "Initial Catalog='Pubs';Integrated Security='SSPI';"  
    Cnxn.Open strCnxn  
    cmd.ActiveConnection = Cnxn  
     ' open recordset  
    rstAuthors.Open cmd, , adOpenStatic, adLockReadOnly  
    'Connection and CommandType are omitted because  
    'a Command object is provided  
  
    Debug.Print "The Parameters collection accessed by index..."  
    Set prm = cmd.Parameters.Item(0)  
    Debug.Print "Parameter name = '"; prm.Name; "', value = '"; prm.Value; "'"  
    Debug.Print  
  
    Debug.Print "The Parameters collection accessed by name..."  
    Set prm = cmd.Parameters.Item("ItemXparm")  
    Debug.Print "Parameter name = '"; prm.Name; "', value = '"; prm.Value; "'"  
    Debug.Print  
  
    Debug.Print "The Fields collection accessed by index..."  
  
    rstAuthors.MoveFirst  
    limit = rstAuthors.Fields.Count - 1  
    For ix = 0 To limit  
       Set fld = rstAuthors.Fields.Item(ix)  
       Debug.Print "Field "; ix; ": Name = '"; fld.Name; _  
                   "', Value = '"; fld.Value; "'"  
    Next ix  
  
    Debug.Print  
  
    Debug.Print "The Fields collection accessed by name..."  
  
    rstAuthors.MoveFirst  
    For ix = 0 To 8  
       Set fld = rstAuthors.Fields.Item(Column(ix))  
       Debug.Print "Field name = '"; fld.Name; "', Value = '"; fld.Value; "'"  
    Next ix  
  
    ' clean up  
    rstAuthors.Close  
    Cnxn.Close  
    Set rstAuthors = Nothing  
    Set Cnxn = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    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  
  
    Set cmd = Nothing  
  
    If Err <> 0 Then  
        MsgBox Err.Source & "-->" & Err.Description, , "Error"  
    End If  
  
End Sub  
'EndItemVB  

另請參閱

Command 物件 (ADO)
Fields 集合 (ADO)
Item 屬性 (ADO)
Parameters 集合 (ADO)
Recordset 物件 (ADO)