基于属性条件查找 UI 自动化元素
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。
本文包含的示例代码展示了如何根据一个或多个特定属性在 UI 自动化树中定位元素。
示例
在以下示例中，指定了一组属性条件，用于标识 AutomationElement 树中的某个（或多个）感兴趣的元素。 然后使用 FindAll 方法搜索所有匹配元素，该方法包含一系列 AndCondition 布尔运算，以限制匹配元素的数量。
备注
在 RootElement 中搜索时，应该尝试仅获取直接子项。 对后代的搜索可能循环访问数百个甚至数千个元素，这可能导致堆栈溢出。 如果尝试在较低级别上获取特定元素，应该从应用程序窗口或者从较低级别的容器中开始搜索。
///--------------------------------------------------------------------
/// <summary>
/// Walks the UI Automation tree of the target and reports the control
/// type of each element it finds in the control view to the client.
/// </summary>
/// <param name="targetTreeViewElement">
/// The root of the search on this iteration.
/// </param>
/// <param name="elementIndex">
/// The TreeView index for this iteration.
/// </param>
/// <remarks>
/// This is a recursive function that maps out the structure of the
/// subtree of the target beginning at the AutomationElement passed in
/// as the rootElement on the first call. This could be, for example,
/// an application window.
/// CAUTION: Do not pass in AutomationElement.RootElement. Attempting
/// to map out the entire subtree of the desktop could take a very
/// long time and even lead to a stack overflow.
/// </remarks>
///--------------------------------------------------------------------
private void FindTreeViewDescendants(
AutomationElement targetTreeViewElement, int treeviewIndex)
{
if (targetTreeViewElement == null)
return;
AutomationElement elementNode =
TreeWalker.ControlViewWalker.GetFirstChild(targetTreeViewElement);
while (elementNode != null)
{
Label elementInfo = new Label();
elementInfo.Margin = new Thickness(0);
clientTreeViews[treeviewIndex].Children.Add(elementInfo);
// Compile information about the control.
elementInfoCompile = new StringBuilder();
string controlName =
(elementNode.Current.Name == "") ?
"Unnamed control" : elementNode.Current.Name;
string autoIdName =
(elementNode.Current.AutomationId == "") ?
"No AutomationID" : elementNode.Current.AutomationId;
elementInfoCompile.Append(controlName)
.Append(" (")
.Append(elementNode.Current.ControlType.LocalizedControlType)
.Append(" - ")
.Append(autoIdName)
.Append(")");
// Test for the control patterns of interest for this sample.
object objPattern;
ExpandCollapsePattern expcolPattern;
if (true == elementNode.TryGetCurrentPattern(ExpandCollapsePattern.Pattern, out objPattern))
{
expcolPattern = objPattern as ExpandCollapsePattern;
if (expcolPattern.Current.ExpandCollapseState != ExpandCollapseState.LeafNode)
{
Button expcolButton = new Button();
expcolButton.Margin = new Thickness(0, 0, 0, 5);
expcolButton.Height = 20;
expcolButton.Width = 100;
expcolButton.Content = "ExpandCollapse";
expcolButton.Tag = expcolPattern;
expcolButton.Click +=
new RoutedEventHandler(ExpandCollapse_Click);
clientTreeViews[treeviewIndex].Children.Add(expcolButton);
}
}
TogglePattern togPattern;
if (true == elementNode.TryGetCurrentPattern(TogglePattern.Pattern, out objPattern))
{
togPattern = objPattern as TogglePattern;
Button togButton = new Button();
togButton.Margin = new Thickness(0, 0, 0, 5);
togButton.Height = 20;
togButton.Width = 100;
togButton.Content = "Toggle";
togButton.Tag = togPattern;
togButton.Click += new RoutedEventHandler(Toggle_Click);
clientTreeViews[treeviewIndex].Children.Add(togButton);
}
InvokePattern invPattern;
if (true == elementNode.TryGetCurrentPattern(InvokePattern.Pattern, out objPattern))
{
invPattern = objPattern as InvokePattern;
Button invButton = new Button();
invButton.Margin = new Thickness(0);
invButton.Height = 20;
invButton.Width = 100;
invButton.Content = "Invoke";
invButton.Tag = invPattern;
invButton.Click += new RoutedEventHandler(Invoke_Click);
clientTreeViews[treeviewIndex].Children.Add(invButton);
}
// Display compiled information about the control.
elementInfo.Content = elementInfoCompile;
Separator sep = new Separator();
clientTreeViews[treeviewIndex].Children.Add(sep);
// Iterate to next element.
// elementNode - Current element.
// treeviewIndex - Index of parent TreeView.
FindTreeViewDescendants(elementNode, treeviewIndex);
elementNode =
TreeWalker.ControlViewWalker.GetNextSibling(elementNode);
}
}
'''--------------------------------------------------------------------
''' <summary>
''' Walks the UI Automation tree of the target and reports the control
''' type of each element it finds in the control view to the client.
''' </summary>
''' <param name="targetTreeViewElement">
''' The root of the search on this iteration.
''' </param>
''' <param name="treeviewIndex">
''' The TreeView index for this iteration.
''' </param>
''' <remarks>
''' This is a recursive function that maps out the structure of the
''' subtree beginning at the AutomationElement passed in as
''' rootElement on the first call. This could be, for example,
''' an application window.
''' CAUTION: Do not pass in AutomationElement.RootElement. Attempting
''' to map out the entire subtree of the desktop could take a very
''' long time and even lead to a stack overflow.
''' </remarks>
'''--------------------------------------------------------------------
Private Sub FindTreeViewDescendants( _
ByVal targetTreeViewElement As AutomationElement, _
ByVal treeviewIndex As Integer)
If (IsNothing(targetTreeViewElement)) Then
Return
End If
Dim elementNode As AutomationElement = _
TreeWalker.ControlViewWalker.GetFirstChild(targetTreeViewElement)
While Not (elementNode Is Nothing)
Dim elementInfo As New Label()
elementInfo.Margin = New Thickness(0)
clientTreeViews(treeviewIndex).Children.Add(elementInfo)
' Compile information about the control.
elementInfoCompile = New StringBuilder()
Dim controlName As String
If (elementNode.Current.Name = "") Then
controlName = "Unnamed control"
Else
controlName = elementNode.Current.Name
End If
Dim autoIdName As String
If (elementNode.Current.AutomationId = "") Then
autoIdName = "No AutomationID"
Else
autoIdName = elementNode.Current.AutomationId
End If
elementInfoCompile.Append(controlName).Append(" (") _
.Append(elementNode.Current.ControlType.LocalizedControlType) _
.Append(" - ").Append(autoIdName).Append(")")
' Test for the control patterns of interest for this sample.
Dim objPattern As Object = Nothing
Dim expcolPattern As ExpandCollapsePattern
If True = elementNode.TryGetCurrentPattern(ExpandCollapsePattern.Pattern, objPattern) Then
expcolPattern = DirectCast(objPattern, ExpandCollapsePattern)
If expcolPattern.Current.ExpandCollapseState <> ExpandCollapseState.LeafNode Then
Dim expcolButton As New Button()
expcolButton.Margin = New Thickness(0, 0, 0, 5)
expcolButton.Height = 20
expcolButton.Width = 100
expcolButton.Content = "ExpandCollapse"
expcolButton.Tag = expcolPattern
AddHandler expcolButton.Click, AddressOf ExpandCollapse_Click
clientTreeViews(treeviewIndex).Children.Add(expcolButton)
End If
End If
Dim togPattern As TogglePattern
If True = elementNode.TryGetCurrentPattern(TogglePattern.Pattern, objPattern) Then
togPattern = DirectCast(objPattern, TogglePattern)
Dim togButton As New Button()
togButton.Margin = New Thickness(0, 0, 0, 5)
togButton.Height = 20
togButton.Width = 100
togButton.Content = "Toggle"
togButton.Tag = togPattern
AddHandler togButton.Click, AddressOf Toggle_Click
clientTreeViews(treeviewIndex).Children.Add(togButton)
End If
Dim invPattern As InvokePattern
If True = elementNode.TryGetCurrentPattern(InvokePattern.Pattern, objPattern) Then
invPattern = DirectCast(objPattern, InvokePattern)
Dim invButton As New Button()
invButton.Margin = New Thickness(0)
invButton.Height = 20
invButton.Width = 100
invButton.Content = "Invoke"
invButton.Tag = invPattern
AddHandler invButton.Click, AddressOf Invoke_Click
clientTreeViews(treeviewIndex).Children.Add(invButton)
End If
' Display compiled information about the control.
elementInfo.Content = elementInfoCompile
Dim sep As New Separator()
clientTreeViews(treeviewIndex).Children.Add(sep)
' Iterate to next element.
' elementNode - Current element.
' treeviewIndex - Index of parent TreeView.
FindTreeViewDescendants(elementNode, treeviewIndex)
elementNode = TreeWalker.ControlViewWalker.GetNextSibling(elementNode)
End While
End Sub