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使用 UI 自动化公开表的内容

备注

本文档适用于想要使用 System.Windows.Automation 命名空间中定义的托管 UI 自动化类的 .NET Framework 开发人员。 有关 UI 自动化的最新信息,请参阅 Windows 自动化 API:UI 自动化

本主题演示如何使用 Microsoft UI 自动化来公开表格控件中每个单元格的内容和内部属性。

示例

下面的代码示例演示如何获取表示表单元格内容的 AutomationElement、获取诸如行和列索引、行和列范围以及行和列标题信息等单元格属性。 此示例使用焦点更改事件处理程序来模拟实现 UI 自动化的表格控件的键盘遍历。 每个表项的信息在焦点更改事件上公开。

备注

由于焦点更改是全局桌面事件,因此应筛选表外的焦点更改事件。 有关相关实现,请参阅 TrackFocus 示例

/// -------------------------------------------------------------------
/// <summary>
/// Starts the target application and returns the AutomationElement
/// obtained from the targets window handle.
/// </summary>
/// <param name="exe">
/// The target application.
/// </param>
/// <param name="filename">
/// The text file to be opened in the target application
/// </param>
/// <returns>
/// An AutomationElement representing the target application.
/// </returns>
/// -------------------------------------------------------------------
private AutomationElement StartTarget(string exe, string filename)
{
    // Start text editor and load with a text file.
    Process p = Process.Start(exe, filename);

    // targetApp --> the root AutomationElement
    AutomationElement targetApp =
        AutomationElement.FromHandle(p.MainWindowHandle);

    return targetApp;
}
/// -------------------------------------------------------------------
/// <summary>
/// Obtain the table control of interest from the target application.
/// </summary>
/// <param name="targetApp">
/// The target application.
/// </param>
/// <returns>
/// An AutomationElement representing a table control.
/// </returns>
/// -------------------------------------------------------------------
private AutomationElement GetTableElement(AutomationElement targetApp)
{
    // The control type we're looking for; in this case 'Document'
    PropertyCondition cond1 =
        new PropertyCondition(
        AutomationElement.ControlTypeProperty,
        ControlType.Table);

    // The control pattern of interest; in this case 'TextPattern'.
    PropertyCondition cond2 =
        new PropertyCondition(
        AutomationElement.IsTablePatternAvailableProperty,
        true);

    AndCondition tableCondition = new AndCondition(cond1, cond2);

    AutomationElement targetTableElement =
        targetApp.FindFirst(TreeScope.Descendants, tableCondition);

    // If targetTableElement is null then a suitable table control
    // was not found.
    return targetTableElement;
}
///--------------------------------------------------------------------
/// <summary>
/// Obtains a TableItemPattern control pattern from an
/// AutomationElement.
/// </summary>
/// <param name="targetControl">
/// The AutomationElement of interest.
/// </param>
/// <returns>
/// A TableItemPattern object.
/// </returns>
///--------------------------------------------------------------------
private TableItemPattern GetTableItemPattern(
    AutomationElement targetControl)
{
    TableItemPattern tableItemPattern = null;

    try
    {
        tableItemPattern =
            targetControl.GetCurrentPattern(
            TableItemPattern.Pattern)
            as TableItemPattern;
    }
    // Object doesn't support the
    // TableItemPattern control pattern
    catch (InvalidOperationException)
    {
        return null;
    }

    return tableItemPattern;
}
///--------------------------------------------------------------------
/// <summary>
/// Obtains a TablePattern control pattern from an
/// AutomationElement.
/// </summary>
/// <param name="targetControl">
/// The AutomationElement of interest.
/// </param>
/// <returns>
/// A TablePattern object.
/// </returns>
///--------------------------------------------------------------------
private TablePattern GetTablePattern(
    AutomationElement targetControl)
{
    TablePattern tablePattern = null;

    try
    {
        tablePattern =
            targetControl.GetCurrentPattern(
            TablePattern.Pattern)
            as TablePattern;
    }
    // Object doesn't support the
    // TablePattern control pattern
    catch (InvalidOperationException)
    {
        return null;
    }

    return tablePattern;
}
///--------------------------------------------------------------------
/// <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>
/// 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);
}

请参阅