Пример метода Supports (Visual Basic)

В этом примере метод Supports используется для отображения параметров, поддерживаемых набором записей, открытым с различными типами курсоров. Для выполнения этой процедуры требуется процедура DisplaySupport.

'BeginSupportsVB  
  
    '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 rstTitles As ADODB.Recordset  
    Dim Cnxn As ADODB.Connection  
    Dim strCnxn As String  
    Dim strSQLTitles As String  
     ' array variables  
    Dim arrCursorType(4) As Integer  
    Dim intIndex As Integer  
  
    ' open connection  
    Set Cnxn = New ADODB.Connection  
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _  
        "Initial Catalog='Pubs';Integrated Security='SSPI';"  
    Cnxn.Open strCnxn  
  
    ' Fill array with CursorType constants  
    arrCursorType(0) = adOpenForwardOnly  
    arrCursorType(1) = adOpenKeyset  
    arrCursorType(2) = adOpenDynamic  
    arrCursorType(3) = adOpenStatic  
  
    ' open recordset using each CursorType and optimistic locking  
    For intIndex = 0 To 3  
        Set rstTitles = New ADODB.Recordset  
        rstTitles.CursorType = arrCursorType(intIndex)  
        rstTitles.LockType = adLockOptimistic  
  
        strSQLTitles = "Titles"  
        rstTitles.Open strSQLTitles, Cnxn, , , adCmdTable  
  
        Select Case arrCursorType(intIndex)  
           Case adOpenForwardOnly  
              Debug.Print "ForwardOnly cursor supports:"  
           Case adOpenKeyset  
              Debug.Print "Keyset cursor supports:"  
           Case adOpenDynamic  
              Debug.Print "Dynamic cursor supports:"  
           Case adOpenStatic  
              Debug.Print "Static cursor supports:"  
        End Select  
  
        ' call the DisplaySupport procedure from below  
        ' to display the supported options  
        DisplaySupport rstTitles  
  
    Next intIndex  
  
    ' clean up  
    rstTitles.Close  
    Cnxn.Close  
    Set rstTitles = Nothing  
    Set Cnxn = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not rstTitles Is Nothing Then  
        If rstTitles.State = adStateOpen Then rstTitles.Close  
    End If  
    Set rstTitles = 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  
'EndSupportsVB  
  
'BeginSupports2VB  
Public Sub DisplaySupport(rstTemp As ADODB.Recordset)  
  
   Dim arrConstants(11) As Long  
   Dim blnSupports As Boolean  
   Dim intIndex As Integer  
  
   ' Fill array with cursor option constants  
   arrConstants(0) = adAddNew  
   arrConstants(1) = adApproxPosition  
   arrConstants(2) = adBookmark  
   arrConstants(3) = adDelete  
   arrConstants(4) = adFind  
   arrConstants(5) = adHoldRecords  
   arrConstants(6) = adMovePrevious  
   arrConstants(7) = adNotify  
   arrConstants(8) = adResync  
   arrConstants(9) = adUpdate  
   arrConstants(10) = adUpdateBatch  
  
   For intIndex = 0 To 10  
      blnSupports = _  
         rstTemp.Supports(arrConstants(intIndex))  
      If blnSupports Then  
         Select Case arrConstants(intIndex)  
            Case adAddNew  
               Debug.Print "   AddNew"  
            Case adApproxPosition  
               Debug.Print "   AbsolutePosition and AbsolutePage"  
            Case adBookmark  
               Debug.Print "   blnkmark"  
            Case adDelete  
               Debug.Print "   Delete"  
            Case adFind  
               Debug.Print "   Find"  
            Case adHoldRecords  
               Debug.Print "   Holding Records"  
            Case adMovePrevious  
               Debug.Print "   MovePrevious and Move"  
            Case adNotify  
               Debug.Print "   Notifications"  
            Case adResync  
               Debug.Print "   Resyncing data"  
            Case adUpdate  
               Debug.Print "   Update"  
            Case adUpdateBatch  
               Debug.Print "   batch updating"  
         End Select  
      End If  
   Next intIndex  
  
End Sub  
'EndSupports2VB  

См. также:

Объект Recordset (ADO)
Метод Supports