StateBag.IsItemDirty(String) Metodo

Definizione

Spazio dei nomi:

System.Web.UI

Assembly:

System.Web.dll

Verifica un oggetto StateItem archiviato nell'oggetto StateBag per valutare se ha subito delle modifiche dopo la chiamata del metodo TrackViewState().

public:
 bool IsItemDirty(System::String ^ key);

public bool IsItemDirty (string key);

member this.IsItemDirty : string -> bool

Public Function IsItemDirty (key As String) As Boolean

Parametri

key

String

Chiave dell'elemento da verificare.

Restituisce

Boolean

true se l'elemento è stato modificato, altrimenti false.

Esempio

Nell'esempio di codice seguente viene illustrato l'uso del IsItemDirty metodo .

// Implement the SaveViewState method. If the StateBag
// that stores the MyItem class's view state contains
// a value for the message property and if the value
// has changed since the TrackViewState method was last 
// called, all view state for this class is deleted, 
// using the StateBag.Clear method,and the new value is added.
object IStateManager.SaveViewState()
{
    // Check whether the message property exists in 
    // the ViewState property, and if it does, check
    // whether it has changed since the most recent
    // TrackViewState method call.
    if (!((IDictionary)_viewstate).Contains("message") || _viewstate.IsItemDirty("message"))
    {
        _viewstate.Clear();
        // Add the _message property to the StateBag.
        _viewstate.Add("message", _message);
    }
    return ((IStateManager)_viewstate).SaveViewState();
}

' Implement the SaveViewState method. If the StateBag
' that stores the MyItem class's view state contains
' a value for the message property and if the value
' has changed since the TrackViewState method was last 
' called, all view state for this class is deleted, 
' using the StateBag.Clear method,and the new value is added.
Function SaveViewState() As Object Implements IStateManager.SaveViewState
    ' Check whether the message property exists in 
    ' the ViewState property, and if it does, check
    ' whether it has changed since the most recent
    ' TrackViewState method call.
    If Not CType(_viewstate, IDictionary).Contains("message") OrElse _viewstate.IsItemDirty("message") Then
        _viewstate.Clear()
        ' Add the _message property to the StateBag.
        _viewstate.Add("message", _message)
    End If
    Return CType(_viewstate, IStateManager).SaveViewState()
End Function 'IStateManager.SaveViewState

Commenti

Questo metodo restituisce false anche se il key parametro non esiste nell'oggetto StateBag .

Vedi anche

• ViewState