GridPattern.GridPatternInformation.ColumnCount Property

 

Gets the number of columns in a grid.

Namespace:   System.Windows.Automation
Assembly:  UIAutomationClient (in UIAutomationClient.dll)

public int ColumnCount { get; }

Property Value

Type: System.Int32

The total number of columns in a grid.

Hidden rows and columns, depending on the provider implementation, may be loaded in the UI Automation tree and will therefore be reflected in the RowCount and ColumnCount properties. If the hidden rows and columns have not yet been loaded they are not counted.

The default value is 0.

In the following example, an event listener is set up for a grid structure change such as a row or column grid item being added or removed from the grid.

///--------------------------------------------------------------------
/// <summary>
/// Set up grid event listeners.
/// </summary>
/// <param name="targetControl">
/// The automation element of interest.
/// </param>
///--------------------------------------------------------------------
private void SetGridEventListeners(AutomationElement targetControl)
{
    StructureChangedEventHandler gridStructureChangedListener = 
        new StructureChangedEventHandler(OnGridStructureChange);
    Automation.AddStructureChangedEventHandler(
        targetControl, 
        TreeScope.Element, 
        gridStructureChangedListener);
}
///--------------------------------------------------------------------
/// <summary>
/// Event handler for grid structure change.
/// </summary>
/// <param name="src">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
///--------------------------------------------------------------------
private void OnGridStructureChange(
    object src, StructureChangedEventArgs 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;
    }

    GridPattern gridPattern = GetGridPattern(sourceElement);

    if (gridPattern == null)
    {
        return;
    }

    if (gridPattern.Current.ColumnCount != columnCount)
    {
        // Column item added.
    }
    else if (gridPattern.Current.RowCount != rowCount)
    {
        // Row item added.
    }
}
// Member variables to track current row and column counts.
private int columnCount = 0;
private int rowCount = 0;

///--------------------------------------------------------------------
/// <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>
/// Obtains a GridPattern control pattern from an 
/// automation element.
/// </summary>
/// <param name="targetControl">
/// The automation element of interest.
/// </param>
/// <returns>
/// A GridPattern object.
/// </returns>
///--------------------------------------------------------------------
private GridPattern GetGridPattern(
    AutomationElement targetControl)
{
    GridPattern gridPattern = null;

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

    return gridPattern;
}

.NET Framework
Available since 3.0
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