.gif "注意") 注意 |
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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）。 |
本主题包含演示如何基于特定的属性在 UI Automation树内查找元素的代码示例。
示例
在下面的示例中，指定了在 AutomationElement 树中标识相关特定元素的一组属性条件。 然后，使用 FindAll 方法搜索所有匹配的元素，该方法合并一系列 AndCondition 布尔运算以限制匹配元素的数量。
| 注意 |
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在从 RootElement 中进行搜索时，应尝试仅获取直接子级。搜索子代可能会循环访问数百甚至数千个元素，从而可能会导致堆栈溢出。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="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 'FindTreeViewDescendants
///--------------------------------------------------------------------
/// <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);
}
}
请参见
任务
InvokePattern, ExpandCollapsePattern, and TogglePattern Sample