ScrollPattern.ScrollPatternInformation.VerticallyScrollable 属性

定义

命名空间:

System.Windows.Automation

程序集:

UIAutomationClient.dll

检索一个值，该值指示 UI 自动化元素是否可垂直滚动。

public:
 property bool VerticallyScrollable { bool get(); };

public bool VerticallyScrollable { get; }

member this.VerticallyScrollable : bool

Public ReadOnly Property VerticallyScrollable As Boolean

属性值

Boolean

如果 UI 自动化元素可水平滚动，则为 true；否则为 false。 默认值是 false。

示例

在以下示例中，ScrollPattern控件模式是从UI 自动化元素获取的，然后用于垂直滚动请求的元素量。

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

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

    return scrollPattern;
}

'''--------------------------------------------------------------------
''' <summary>
''' Obtains a ScrollPattern control pattern from an 
''' automation element.
''' </summary>
''' <param name="targetControl">
''' The automation element of interest.
''' </param>
''' <returns>
''' A ScrollPattern object.
''' </returns>
'''--------------------------------------------------------------------
Private Function GetScrollPattern( _
ByVal targetControl As AutomationElement) As ScrollPattern
    Dim scrollPattern As ScrollPattern = Nothing

    Try
        scrollPattern = DirectCast( _
        targetControl.GetCurrentPattern(scrollPattern.Pattern), _
        ScrollPattern)
    Catch
        ' Object doesn't support the ScrollPattern control pattern
        Return Nothing
    End Try

    Return scrollPattern

End Function 'GetScrollPattern

///--------------------------------------------------------------------
/// <summary>
/// Obtains a ScrollPattern control pattern from an automation 
/// element and attempts to horizontally scroll the requested amount.
/// </summary>
/// <param name="targetControl">
/// The automation element of interest.
/// </param>
/// <param name="vScrollAmount">
/// The requested vertical scroll amount.
/// </param>
///--------------------------------------------------------------------
private void ScrollElementVertically(
    AutomationElement targetControl,
    ScrollAmount vScrollAmount)
{
    if (targetControl == null)
    {
        throw new ArgumentNullException(
            "AutomationElement argument cannot be null.");
    }

    ScrollPattern scrollPattern = GetScrollPattern(targetControl);

    if (scrollPattern == null)
    {
        return;
    }
    
    if (!scrollPattern.Current.VerticallyScrollable)
    {
        return;
    }

    try
    {
        scrollPattern.ScrollVertical(vScrollAmount);
    }
    catch (InvalidOperationException)
    {
        // Control not able to scroll in the direction requested;
        // when scrollable property of that direction is False
        // TO DO: error handling.
    }
    catch (ArgumentException)
    {
        // If a control supports SmallIncrement values exclusively 
        // for horizontal or vertical scrolling but a LargeIncrement 
        // value (NaN if not supported) is passed in.
        // TO DO: error handling.
    }
}

'''--------------------------------------------------------------------
''' <summary>
''' Obtains a ScrollPattern control pattern from an automation 
''' element and attempts to horizontally scroll the requested amount.
''' </summary>
''' <param name="targetControl">
''' The automation element of interest.
''' </param>
''' <param name="vScrollAmount">
''' The requested vertical scroll amount.
''' </param>
'''--------------------------------------------------------------------
Private Sub ScrollElementVertically( _
ByVal targetControl As AutomationElement, _
ByVal vScrollAmount As ScrollAmount)
    If targetControl Is Nothing Then
        Throw New ArgumentNullException( _
        "AutomationElement argument cannot be null.")
    End If

    Dim scrollPattern As ScrollPattern = GetScrollPattern(targetControl)

    If scrollPattern Is Nothing Then
        Return
    End If

    If Not scrollPattern.Current.VerticallyScrollable Then
        Return
    End If

    Try
        scrollPattern.ScrollVertical(vScrollAmount)
    Catch exc As InvalidOperationException
        ' Control not able to scroll in the direction requested;
        ' when scrollable property of that direction is False
        ' TO DO: error handling.
    Catch exc As ArgumentException
        ' If a control supports SmallIncrement values exclusively 
        ' for horizontal or vertical scrolling but a LargeIncrement 
        ' value (NaN if not supported) is passed in.
        ' TO DO: error handling.
    End Try

End Sub

注解

此属性可以是动态的。 例如，UI 自动化元素的内容区域可能不大于当前可查看区域，这意味着VerticallyScrollable。false 但是，调整UI 自动化元素或添加子项的大小可能会增加内容区域超出可查看区域的范围，这表示VerticallyScrollable。true