Count 属性示例 (VB)

此示例演示 Employee 数据库中具有两个集合的 Count 属性。 该属性获取每个集合中的对象数，并设置用于枚举这些集合的循环的上限。 不使用 Count 属性枚举这些集合的另一种方法是使用 For Each...Next 语句。

'BeginCountVB  
  
    '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 rstEmployees As ADODB.Recordset  
    Dim Cnxn As ADODB.Connection  
    Dim strSQLEmployees As String  
    Dim strCnxn As String  
  
    Dim intLoop As Integer  
  
    ' Open a connection  
    Set Cnxn = New ADODB.Connection  
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _  
        "Initial Catalog='Northwind';Integrated Security='SSPI';"  
    Cnxn.Open strCnxn  
  
    ' Open recordset with data from Employee table  
    Set rstEmployees = New ADODB.Recordset  
    strSQLEmployees = "Employee"  
    'rstEmployees.Open strSQLEmployee, Cnxn, , , adCmdTable  
    rstEmployees.Open strSQLEmployees, Cnxn, adOpenForwardOnly, adLockReadOnly, adCmdTable  
    'the above two lines opening the recordset are identical as  
    'the default values for CursorType and LockType arguments match those specified  
  
    ' Print information about Fields collection  
    Debug.Print rstEmployees.Fields.Count & " Fields in Employee"  
  
    For intLoop = 0 To rstEmployees.Fields.Count - 1  
        Debug.Print "   " & rstEmployees.Fields(intLoop).Name  
    Next intLoop  
  
    ' Print information about Properties collection  
    Debug.Print rstEmployees.Properties.Count & " Properties in Employee"  
  
    For intLoop = 0 To rstEmployees.Properties.Count - 1  
        Debug.Print "   " & rstEmployees.Properties(intLoop).Name  
    Next intLoop  
  
    ' clean up  
    rstEmployees.Close  
    Cnxn.Close  
    Set rstEmployees = Nothing  
    Set Cnxn = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not rstEmployees Is Nothing Then  
        If rstEmployees.State = adStateOpen Then rstEmployees.Close  
    End If  
    Set rstEmployees = 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  
'EndCountVB  

另请参阅

Count 属性 (ADO)