GridPattern.GetItem(Int32, Int32) Método

Definição

Namespace:

System.Windows.Automation

Assembly:

UIAutomationClient.dll

Recupera um AutomationElement que representa a célula especificada.

public:
 System::Windows::Automation::AutomationElement ^ GetItem(int row, int column);

public System.Windows.Automation.AutomationElement GetItem (int row, int column);

member this.GetItem : int * int -> System.Windows.Automation.AutomationElement

Public Function GetItem (row As Integer, column As Integer) As AutomationElement

Parâmetros

row

Int32

O número ordinal da linha de interesse.

column

Int32

O número ordinal da coluna de interesse.

Retornos

AutomationElement

Um AutomationElement que representa a célula recuperada.

Exceções

ArgumentOutOfRangeException

A coordenada de linha ou coluna solicitada é menor que zero.

- ou -

A coordenada da linha solicitada é maior do que o RowCount ou a coordenada da coluna é maior do que o ColumnCount.

Exemplos

No exemplo a seguir, um AutomationFocusChangedEvent ouvinte é declarado para acompanhar a passagem de itens de grade em um contêiner de grade. As propriedades do item são ecoadas no console em cada evento de alteração de foco.

///--------------------------------------------------------------------
/// <summary>
/// Set up grid item event listeners.
/// </summary>
/// <param name="targetControl">
/// The grid item container of interest.
/// </param>
///--------------------------------------------------------------------
private void SetGridItemEventListeners(AutomationElement targetControl)
{
    AutomationFocusChangedEventHandler gridItemFocusChangedListener =
        new AutomationFocusChangedEventHandler(OnGridItemFocusChange);
    Automation.AddAutomationFocusChangedEventHandler(
        gridItemFocusChangedListener);
}

'''--------------------------------------------------------------------
''' <summary>
''' Set up grid item event listeners.
''' </summary>
''' <param name="targetControl">
''' The grid item container of interest.
''' </param>
'''--------------------------------------------------------------------
Private Sub SetGridItemEventListeners( _
ByVal targetControl As AutomationElement)
    Dim gridItemFocusChangedListener As AutomationFocusChangedEventHandler = _
    AddressOf OnGridItemFocusChange
    Automation.AddAutomationFocusChangedEventHandler( _
    gridItemFocusChangedListener)
End Sub

///--------------------------------------------------------------------
/// <summary>
/// Event handler for grid item focus change.
/// Can be used to track traversal of individual grid items 
/// within a grid.
/// </summary>
/// <param name="src">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
///--------------------------------------------------------------------
private void OnGridItemFocusChange(
    object src, AutomationFocusChangedEventArgs e)
{
    // Make sure the element still exists. Elements such as tooltips
    // can disappear before the event is processed.
    AutomationElement sourceElement;
    try
    {
        sourceElement = src as AutomationElement;
    }
    catch (ElementNotAvailableException)
    {
        return;
    }

    // Gets a GridItemPattern from the source of the event.
    GridItemPattern gridItemPattern = 
        GetGridItemPattern(sourceElement);

    if (gridItemPattern == null)
    {
        return;
    }

    // Gets a GridPattern from the grid container.
    GridPattern gridPattern = 
        GetGridPattern(gridItemPattern.Current.ContainingGrid);

    if (gridPattern == null)
    {
        return;
    }

    AutomationElement gridItem = null;
    try
    {
        gridItem = gridPattern.GetItem(
        gridItemPattern.Current.Row, 
        gridItemPattern.Current.Column);
    }
    catch (ArgumentOutOfRangeException)
    {
        // If the requested row coordinate is larger than the RowCount 
        // or the column coordinate is larger than the ColumnCount.
        // -- OR --
        // If either of the requested row or column coordinates 
        // are less than zero.
        // TO DO: error handling.
    }

    // Further event processing can be done at this point.
    // For the purposes of this sample we just report item properties.
    StringBuilder gridItemReport = new StringBuilder();
    gridItemReport.AppendLine(
        gridItemPattern.Current.Row.ToString()).AppendLine(
        gridItemPattern.Current.Column.ToString()).AppendLine(
        gridItemPattern.Current.RowSpan.ToString()).AppendLine(
        gridItemPattern.Current.ColumnSpan.ToString()).AppendLine(
        gridItem.Current.AutomationId.ToString());
    Console.WriteLine(gridItemReport.ToString());
}

///--------------------------------------------------------------------
/// <summary>
/// Handles our application shutdown.
/// </summary>
/// <param name="args">Event arguments.</param>
///--------------------------------------------------------------------
protected override void OnExit(System.Windows.ExitEventArgs args)
{
    Automation.RemoveAllEventHandlers();
    base.OnExit(args);
}

'''--------------------------------------------------------------------
''' <summary>
''' Event handler for grid item focus change.
''' Can be used to track traversal of individual grid items 
''' within a grid.
''' </summary>
''' <param name="src">Object that raised the event.</param>
''' <param name="e">Event arguments.</param>
'''--------------------------------------------------------------------
Private Sub OnGridItemFocusChange( _
ByVal src As Object, ByVal e As AutomationFocusChangedEventArgs)
    ' Make sure the element still exists. Elements such as tooltips
    ' can disappear before the event is processed.
    Dim sourceElement As AutomationElement
    Try
        sourceElement = DirectCast(src, AutomationElement)
    Catch exc As ElementNotAvailableException
        Return
    End Try

    ' Gets a GridItemPattern from the source of the event.
    Dim gridItemPattern As GridItemPattern = _
    GetGridItemPattern(sourceElement)

    If gridItemPattern Is Nothing Then
        Return
    End If

    ' Gets a GridPattern from the grid container.
    Dim gridPattern As GridPattern = _
    GetGridPattern(gridItemPattern.Current.ContainingGrid)

    If gridPattern Is Nothing Then
        Return
    End If

    Dim gridItem As AutomationElement = Nothing
    Try
        gridItem = gridPattern.GetItem( _
        gridItemPattern.Current.Row, gridItemPattern.Current.Column)
    Catch
        ' If the requested row coordinate is larger than the RowCount 
        ' or the column coordinate is larger than the ColumnCount.
        ' -- OR --
        ' If either of the requested row or column coordinates 
        ' are less than zero.
        ' TO DO: error handling.
    End Try

    ' Further event processing can be done at this point.
    ' For the purposes of this sample we just report item properties.
    Dim gridItemReport As New StringBuilder()
    gridItemReport.AppendLine( _
    gridItemPattern.Current.Row.ToString()).AppendLine( _
    gridItemPattern.Current.Column.ToString()).AppendLine( _
    gridItemPattern.Current.RowSpan.ToString()).AppendLine( _
    gridItemPattern.Current.ColumnSpan.ToString()).AppendLine( _
    gridItem.Current.AutomationId.ToString())
    Console.WriteLine(gridItemReport.ToString())

End Sub


'''--------------------------------------------------------------------
''' <summary>
''' Handles our application shutdown.
''' </summary>
''' <param name="args">Event arguments.</param>
'''--------------------------------------------------------------------
Protected Overrides Sub OnExit(ByVal args As System.Windows.ExitEventArgs) 
    Automation.RemoveAllEventHandlers()
    MyBase.OnExit(args)

End Sub

Comentários

As coordenadas de grade são baseadas em zero com a célula superior esquerda (ou superior direita, dependendo da localidade) com coordenadas (0,0).

Se uma célula estiver vazia, um elemento de Automação da Interface do Usuário ainda será retornado para dar suporte à recuperação da ContainingGrid propriedade para essa célula. Isso é possível quando o layout de elementos filho na grade é semelhante a uma matriz irregular, conforme mostrado aqui.

Exemplo de um controle de grade com coordenadas vazias