GetRows 方法范例 (VB)

本范例使用 GetRows 方法从 Recordset 中检索指定数目的行，并用结果数据填充一个数组。在两种情况下，GetRows 方法返回的行将少于所需的数目：一种情况是到达了 EOF，另一种情况是 GetRows 试图检索被其他用户删除的记录。仅在发生第二种情况时，该函数才返回 False。运行此过程需要 GetRowsOK 函数。

Public Sub GetRowsX()

    Dim rstEmployees As ADODB.Recordset
    Dim strCnn As String
    Dim strMessage As String
    Dim intRows As Integer
    Dim avarRecords As Variant
    Dim intRecord As Integer

    ' Open recordset with names and hire dates from employee table.
        strCnn = "Provider=sqloledb;" & _
        "Data Source=srv;Initial Catalog=Pubs;User Id=sa;Password=; "
    Set rstEmployees = New ADODB.Recordset
    rstEmployees.Open "SELECT fName, lName, hire_date " & _
        "FROM Employee ORDER BY lName", strCnn, , , adCmdText

    Do While True
        ' Get user input for number of rows.
        strMessage = "Enter number of rows to retrieve."
        intRows = Val(InputBox(strMessage))

        If intRows <= 0 Then Exit Do

        ' If GetRowsOK is successful, print the results,
        ' noting if the end of the file was reached.
        If GetRowsOK(rstEmployees, intRows, _
                avarRecords) Then
            If intRows > UBound(avarRecords, 2) + 1 Then
                Debug.Print "(Not enough records in " & _
                    "Recordset to retrieve " & intRows & _
                    " rows.)"
            End If
            Debug.Print UBound(avarRecords, 2) + 1 & _
                " records found."

            ' Print the retrieved data.
            For intRecord = 0 To UBound(avarRecords, 2)
                Debug.Print "  " & _
                    avarRecords(0, intRecord) & " " & _
                    avarRecords(1, intRecord) & ", " & _
                    avarRecords(2, intRecord)
            Next intRecord
        Else
            ' Assuming the GetRows error was due to data
            ' changes by another user, use Requery to
            ' refresh the Recordset and start over.
            If MsgBox("GetRows failed--retry?", _
                    vbYesNo) = vbYes Then
                rstEmployees.Requery
            Else
                Debug.Print "GetRows failed!"
                Exit Do
            End If
        End If

        ' Because using GetRows leaves the current
        ' record pointer at the last record accessed,
        ' move the pointer back to the beginning of the
        ' Recordset before looping back for another search.
        rstEmployees.MoveFirst
    Loop

    rstEmployees.Close

End Sub

Public Function GetRowsOK(rstTemp As ADODB.Recordset, _
    intNumber As Integer, avarData As Variant) As Boolean

    ' Store results of GetRows method in array.
    avarData = rstTemp.GetRows(intNumber)
    ' Return False only if fewer than the desired
    ' number of rows were returned, but not because the
    ' end of the Recordset was reached.
    If intNumber > UBound(avarData, 2) + 1 And _
            Not rstTemp.EOF Then
        GetRowsOK = False
    Else
        GetRowsOK = True
    End If

End Function