SelectionItemPattern.RemoveFromSelection Methode

Definition

Namespace:

System.Windows.Automation

Assembly:

UIAutomationClient.dll

Entfernt das aktuelle Element aus der Sammlung ausgewählter Elemente.

public:
 void RemoveFromSelection();

public void RemoveFromSelection ();

member this.RemoveFromSelection : unit -> unit

Public Sub RemoveFromSelection ()

Ausnahmen

InvalidOperationException

Es wird versucht, aus einem Auswahlcontainer mit einer Auswahl, in dem IsSelectionRequiredProperty = true ist und ein anderes Element bereits ausgewählt wurde, eine Auswahl zu entfernen.

Beispiele

Im folgenden Beispiel wird gezeigt, wie ein Element aus der Auflistung der aktuell ausgewählten Elemente entfernt wird.

///--------------------------------------------------------------------
/// <summary>
/// Retrieves the selection container for a selection item.
/// </summary>
/// <param name="selectionItem">
/// An automation element that supports SelectionItemPattern.
/// </param>
///--------------------------------------------------------------------
private AutomationElement GetSelectionItemContainer(
    AutomationElement selectionItem)
{
    // Selection item cannot be null
    if (selectionItem == null)
    {
        throw new ArgumentException();
    }

    SelectionItemPattern selectionItemPattern = 
        selectionItem.GetCurrentPattern(SelectionItemPattern.Pattern) 
        as SelectionItemPattern;
    if (selectionItemPattern == null)
    {
        return null;
    }
    else
    {
        return selectionItemPattern.Current.SelectionContainer; 
    }
}

'''--------------------------------------------------------------------
''' <summary>
''' Retrieves the selection container for a selection item.
''' </summary>
''' <param name="selectionItem">
''' An automation element that supports SelectionItemPattern.
''' </param>
'''--------------------------------------------------------------------
Private Function GetSelectionItemContainer( _
ByVal selectionItem As AutomationElement) As AutomationElement
    ' Selection item cannot be null
    If selectionItem Is Nothing Then
        Throw New ArgumentException()
    End If

    Dim selectionItemPattern As SelectionItemPattern = _
    DirectCast(selectionItem.GetCurrentPattern( _
    selectionItemPattern.Pattern), SelectionItemPattern)
    If selectionItemPattern Is Nothing Then
        Return Nothing
    Else
        Return selectionItemPattern.Current.SelectionContainer
    End If
End Function 'GetSelectionItemContainer

///--------------------------------------------------------------------
/// <summary>
/// Attempts to remove the current item from a collection 
/// of selected items. 
/// </summary>
/// <param name="selectionItem">
/// An automation element that supports SelectionItemPattern.
/// </param>
///--------------------------------------------------------------------
private void RemoveItemFromSelection(AutomationElement selectionItem)
{
    if (selectionItem == null)
    {
        throw new ArgumentNullException(
            "Argument cannot be null or empty.");
    }

    AutomationElement selectionContainer =
        GetSelectionItemContainer(selectionItem);

    // Selection container cannot be null
    if (selectionContainer == null)
    {
        throw new ElementNotAvailableException();
    }

    SelectionPattern selectionPattern =
        selectionContainer.GetCurrentPattern(SelectionPattern.Pattern)
        as SelectionPattern;

    if (selectionPattern == null)
    {
        return;
    }

    // Check if a selection is required
    if (selectionPattern.Current.IsSelectionRequired && 
        (selectionPattern.Current.GetSelection().GetLength(0) <= 1))
    {
        return;
    }

    SelectionItemPattern selectionItemPattern =
        selectionItem.GetCurrentPattern(
        SelectionItemPattern.Pattern)
        as SelectionItemPattern;
    if ((selectionItemPattern != null) && 
        selectionItemPattern.Current.IsSelected)
    {
        try
        {
            selectionItemPattern.RemoveFromSelection();
        }
        catch (InvalidOperationException)
        {
            // Unable to remove from selection
            return;
        }
    }
}

'''--------------------------------------------------------------------
''' <summary>
''' Attempts to remove the current item from a collection 
''' of selected items. 
''' </summary>
''' <param name="selectionItem">
''' An automation element that supports SelectionItemPattern.
''' </param>
'''--------------------------------------------------------------------
Private Sub RemoveItemFromSelection( _
ByVal selectionItem As AutomationElement)
    If selectionItem Is Nothing Then
        Throw New ArgumentNullException( _
        "Argument cannot be null or empty.")
    End If

    Dim selectionContainer As AutomationElement = _
    GetSelectionItemContainer(selectionItem)

    ' Selection container cannot be null
    If selectionContainer Is Nothing Then
        Throw New ElementNotAvailableException()
    End If

    Dim selectionPattern As SelectionPattern = DirectCast( _
    selectionContainer.GetCurrentPattern(selectionPattern.Pattern), _
    SelectionPattern)

    If selectionPattern Is Nothing Then
        Return
    End If

    ' Check if a selection is required
    If selectionPattern.Current.IsSelectionRequired AndAlso _
    selectionPattern.Current.GetSelection().GetLength(0) <= 1 Then
        Return
    End If

    Dim selectionItemPattern As SelectionItemPattern = DirectCast( _
    selectionItem.GetCurrentPattern(selectionItemPattern.Pattern), _
    SelectionItemPattern)

    If Not (selectionItemPattern Is Nothing) AndAlso selectionItemPattern.Current.IsSelected Then
        Try
            selectionItemPattern.RemoveFromSelection()
        Catch
            ' Unable to remove from selection
            Return
        End Try
    End If
End Sub