ConnectionString、ConnectionTimeout 和 State 屬性範例 (VB)

此範例示範各種使用 ConnectionString (英文) 屬性開啟 Connection (英文) 物件的方式。 它也會使用 ConnectionTimeout (英文) 屬性來設定連線逾時期間，並使用 State (英文) 屬性來檢查連線的狀態。 需要 GetState 函數，此程序才能執行。

注意

如果您要連線至支援 Windows 驗證的資料來源提供者，您應該指定 Trusted_Connection=yes 或 Integrated Security = SSPI，而非在連接字串中指定使用者識別碼和密碼資訊。

'BeginConnectionStringVB  
  
    'To integrate this code replace  
    'the database, DSN or Data Source values  
  
Public Sub Main()  
    On Error GoTo ErrorHandler  
  
    Dim Cnxn1 As ADODB.Connection  
    Dim Cnxn2 As ADODB.Connection  
    Dim Cnxn3 As ADODB.Connection  
    Dim Cnxn4 As ADODB.Connection  
  
     ' Open a connection without using a Data Source Name (DSN)  
    Set Cnxn1 = New ADODB.Connection  
    Cnxn1.ConnectionString = "Provider='sqloledb';Data Source='MySqlServer';" & _  
        "Initial Catalog='Pubs';Integrated Security='SSPI';"  
    Cnxn1.Open  
    MsgBox "Cnxn1 state: " & GetState(Cnxn1.State)  
  
     ' Open a connection using a DSN and ODBC tags  
     ' It is assumed that you have created DSN 'Pubs' with a user name as  
     ' 'MyUserId' and password as 'MyPassword'.  
    Set Cnxn2 = New ADODB.Connection  
    Cnxn2.ConnectionString = "Data Source='Pubs';" & _  
        "User ID='MyUserId';Password='MyPassword';"  
    Cnxn2.ConnectionTimeout = 30  
    Cnxn2.Open  
    MsgBox "Cnxn2 state: " & GetState(Cnxn2.State)  
  
     ' Open a connection using a DSN and OLE DB tags  
     ' It is assumed that you have created DSN 'Pubs1' with windows authentication.  
    Set Cnxn3 = New ADODB.Connection  
    Cnxn3.ConnectionString = "Data Source='Pubs1';"  
    Cnxn3.Open  
    MsgBox "Cnxn2 state: " & GetState(Cnxn3.State)  
  
     ' Open a connection using a DSN and individual  
     ' arguments instead of a connection string  
     ' It is assumed that you have created DSN 'Pubs' with a user name as  
     ' 'MyUserId' and password as 'MyPassword'.  
    Set Cnxn4 = New ADODB.Connection  
    Cnxn4.Open "Pubs", "MyUserId", "MyPassword"  
    MsgBox "Cnxn4 state: " & GetState(Cnxn4.State)  
  
    ' clean up  
    Cnxn1.Close  
    Cnxn2.Close  
    Cnxn3.Close  
    Cnxn4.Close  
    Set Cnxn1 = Nothing  
    Set Cnxn2 = Nothing  
    Set Cnxn3 = Nothing  
    Set Cnxn4 = Nothing  
    Exit Sub  
  
ErrorHandler:  
    ' clean up  
    If Not Cnxn1 Is Nothing Then  
        If Cnxn1.State = adStateOpen Then Cnxn1.Close  
    End If  
    Set Cnxn1 = Nothing  
  
    If Not Cnxn2 Is Nothing Then  
        If Cnxn2.State = adStateOpen Then Cnxn2.Close  
    End If  
    Set Cnxn2 = Nothing  
  
    If Not Cnxn3 Is Nothing Then  
        If Cnxn3.State = adStateOpen Then Cnxn3.Close  
    End If  
    Set Cnxn3 = Nothing  
  
    If Not Cnxn4 Is Nothing Then  
        If Cnxn4.State = adStateOpen Then Cnxn4.Close  
    End If  
    Set Cnxn4 = Nothing  
  
    If Err <> 0 Then  
        MsgBox Err.Source & "-->" & Err.Description, , "Error"  
    End If  
End Sub  
  
Public Function GetState(intState As Integer) As String  
  
   Select Case intState  
      Case adStateClosed  
         GetState = "adStateClosed"  
      Case adStateOpen  
         GetState = "adStateOpen"  
   End Select  
  
End Function  
'EndConnectionStringVB  

另請參閱

Connection 物件 (ADO)
ConnectionString 屬性 (ADO)
ConnectionTimeout 屬性 (ADO)
State 屬性 (ADO)