使用 UI 自动化获取复选框的切换状态

注意
本文档的目标读者是欲使用 System.Windows.Automation 命名空间中定义的托管 UI Automation类的 .NET Framework 开发人员。有关 UI Automation的最新信息，请参见 Windows Automation API: UI Automation（Windows 自动化 API：UI 自动化）。

本主题演示如何使用 Microsoft UI Automation来获取控件的切换状态。

示例

此示例使用 AutomationElement 类的 GetCurrentPattern 方法从控件中获取 TogglePattern 对象，并返回它的 ToggleState 属性。

        ''' <summary>
        ''' Gets the toggle state of an element in the target application.
        ''' </summary>
        ''' <param name="element">The target element.</param>
        Private Function IsElementToggledOn(ByVal element As AutomationElement) As Boolean
            If element Is Nothing Then
                ' TODO: Invalid parameter error handling.
                Return False
            End If

            Dim objPattern As Object = Nothing
            Dim togPattern As TogglePattern
            If True = element.TryGetCurrentPattern(TogglePattern.Pattern, objPattern) Then
                togPattern = TryCast(objPattern, TogglePattern)
                Return togPattern.Current.ToggleState = ToggleState.On
            End If
            ' TODO: Object doesn't support TogglePattern error handling.
            Return False
        End Function

/// <summary>
/// Gets the toggle state of an element in the target application.
/// </summary>
/// <param name="element">The target element.</param>
private bool IsElementToggledOn(AutomationElement element)
{
    if (element == null)
    {
        // TODO: Invalid parameter error handling.
        return false;
    }

    Object objPattern;
    TogglePattern togPattern;
    if (true == element.TryGetCurrentPattern(TogglePattern.Pattern, out objPattern))
    {
        togPattern = objPattern as TogglePattern;
        return togPattern.Current.ToggleState == ToggleState.On;
    }
    // TODO: Object doesn't support TogglePattern error handling.
    return false;
}