TableItemPattern.TableItemPatternInformation.GetColumnHeaderItems Method

public:
 cli::array <System::Windows::Automation::AutomationElement ^> ^ GetColumnHeaderItems();

public System.Windows.Automation.AutomationElement[] GetColumnHeaderItems ();

member this.GetColumnHeaderItems : unit -> System.Windows.Automation.AutomationElement[]

Public Function GetColumnHeaderItems () As AutomationElement()

Returns

A collection of column header elements. The default is an empty array.

Examples

In the following example, an AutomationFocusChangedEvent listener is declared to track the traversal of table items within a table container. Item properties are recorded upon each focus changed event.

///--------------------------------------------------------------------
/// <summary>
/// Set up table item event listeners.
/// </summary>
/// <remarks>
/// The event listener is essentially a focus change listener.
/// Since this is a global desktop listener, a filter would be required 
/// to ignore focus change events outside the table.
/// </remarks>
///--------------------------------------------------------------------
private void SetTableItemEventListeners()
{
    AutomationFocusChangedEventHandler tableItemFocusChangedListener =
        new AutomationFocusChangedEventHandler(OnTableItemFocusChange);
    Automation.AddAutomationFocusChangedEventHandler(
        tableItemFocusChangedListener);
}

'''--------------------------------------------------------------------
''' <summary>
''' Set up table item event listeners.
''' </summary>
''' <remarks>
''' The event listener is essentially a focus change listener.
''' Since this is a global desktop listener, a filter would be required 
''' to ignore focus change events outside the table.
''' </remarks>
'''--------------------------------------------------------------------
Private Sub SetTableItemEventListeners( _
ByVal targetControl As AutomationElement)
    Dim tableItemFocusChangedListener As AutomationFocusChangedEventHandler = _
    AddressOf OnTableItemFocusChange
    Automation.AddAutomationFocusChangedEventHandler( _
    tableItemFocusChangedListener)

End Sub

///--------------------------------------------------------------------
/// <summary>
/// Event handler for table item focus change.
/// Can be used to track traversal of individual table items 
/// within a table.
/// </summary>
/// <param name="src">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
///--------------------------------------------------------------------
private void OnTableItemFocusChange(
    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;
    }

    // Get a TableItemPattern from the source of the event.
    TableItemPattern tableItemPattern =
        GetTableItemPattern(sourceElement);

    if (tableItemPattern == null)
    {
        return;
    }

    // Get a TablePattern from the container of the current element.
    TablePattern tablePattern =
        GetTablePattern(tableItemPattern.Current.ContainingGrid);

    if (tablePattern == null)
    {
        return;
    }

    AutomationElement tableItem = null;
    try
    {
        tableItem = tablePattern.GetItem(
        tableItemPattern.Current.Row,
        tableItemPattern.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 
        // is less than zero.
        // TO DO: error handling.
    }

    // Further event processing can be done at this point.
    // For the purposes of this sample we can just record item properties.
    string controlType = 
        tableItem.Current.ControlType.LocalizedControlType;
    AutomationElement[] columnHeaders = 
        tableItemPattern.Current.GetColumnHeaderItems();
    AutomationElement[] rowHeaders = 
        tableItemPattern.Current.GetRowHeaderItems();
    int itemRow = tableItemPattern.Current.Row;
    int itemColumn = tableItemPattern.Current.Column;
    int itemRowSpan = tableItemPattern.Current.RowSpan;
    int itemColumnSpan = tableItemPattern.Current.ColumnSpan;
}

///--------------------------------------------------------------------
/// <summary>
/// Handles the 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 table item focus change.
''' Can be used to track traversal of individual table items 
''' within a table.
''' </summary>
''' <param name="src">Object that raised the event.</param>
''' <param name="e">Event arguments.</param>
'''--------------------------------------------------------------------
Private Sub OnTableItemFocusChange( _
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

    ' Get a TableItemPattern from the source of the event.
    Dim tableItemPattern As TableItemPattern = _
    GetTableItemPattern(sourceElement)

    If tableItemPattern Is Nothing Then
        Return
    End If

    ' Get a TablePattern from the container of the current element.
    Dim tablePattern As TablePattern = _
    GetTablePattern(tableItemPattern.Current.ContainingGrid)

    If tablePattern Is Nothing Then
        Return
    End If

    Dim tableItem As AutomationElement = Nothing
    Try
        tableItem = tablePattern.GetItem( _
        tableItemPattern.Current.Row, tableItemPattern.Current.Column)

    Catch exc As 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 
        ' is 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 can just record item properties.
    Dim controlType As String = _
        tableItem.Current.ControlType.LocalizedControlType
    Dim columnHeaders As AutomationElement() = _
    tableItemPattern.Current.GetColumnHeaderItems()
    Dim rowHeaders As AutomationElement() = _
    tableItemPattern.Current.GetRowHeaderItems()
    Dim itemRow As Integer = tableItemPattern.Current.Row
    Dim itemColumn As Integer = tableItemPattern.Current.Column
    Dim itemRowSpan As Integer = tableItemPattern.Current.RowSpan
    Dim itemColumnSpan As Integer = tableItemPattern.Current.ColumnSpan

End Sub


'''--------------------------------------------------------------------
''' <summary>
''' Handles the 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

Applies to

See also

• Expose the Content of a Table Using UI Automation