findwindowwex随机失败获得子窗口句柄

Question

我有一个VB。. NET 4.6.1桌面应用程序，已经使用FindWindow和FindWindowEx超过2年没有问题，定位MDI子窗口和捕获窗口标题文本，它一直完美地工作，直到最近。
现在的行为是我的应用程序只能成功地获得MDI客户端窗口句柄，如果我回到父窗口或MDI客户端，并单击任何一个窗口的任何地方，然后返回到我的应用程序，过程成功。

我试过添加线程睡眠事件、动作连续多次在一个循环中运行,调用AppActivate方法使用进程ID(思考我需要再次执行),我的下一个方法思想,试图向父窗口发送一个单击事件之前,我的动作被执行或者使用枚举所有子窗口的家长,希望有人可以建议一些因为我在一个路障,多年来一直在这样做,但这个对我没有意义,我怀疑这与软件公司最近的所有权和他们修改本节有关，但我不知道为什么它会干扰这些根级API方法。

示例代码:

MDIhWnd = FindWindowEx(ParenthWnd, IntPtr.Zero, "WindowsForms10.MDICLIENT.app.0.34f5582_r7_ad1", Nothing)
'Threading.Thread.Sleep(100)
'AppActivate(proc(0).Id)
If MDIhWnd = 0 Then
Threading.Thread.Sleep(100)
'Dim hw = GetTopWindow(ParenthWnd)
For i = 0 To 500
AppActivate(proc(0).Id)
MDIhWnd = FindWindowEx(ParenthWnd, IntPtr.Zero, "WindowsForms10.MDICLIENT.app.0.34f5582_r7_ad1", Nothing)
If MDIhWnd <> 0 Then
Exit For
End If
Next
End If

Answer 1

我的解决方案是，基于上述建议，使用UI自动化，我我以前从来没有使用过它，但是在看过之后，我试了一下我发现它确实简化了我从第三方应用程序窗口用MDI客户端接口捕获窗口文本的需要。

下面是VB的一个小版本。NET的过程中，任何人需要做的同一件事:

Imports System.Windows.Automation
' You will also need references to UIAutomationClient, and UIAutomationTypes
Private Sub test_ui_automation()        
Dim ParenthWnd As Integer = 0
Dim _AutomationElementA As System.Windows.Automation.AutomationElement = Nothing
Dim _AutomationElementB As System.Windows.Automation.AutomationElement = Nothing
Dim _AutomationElementC As System.Windows.Automation.AutomationElement = Nothing
Dim propCondition As Condition
Try
'Parent Windows Process Stuff
ParenthWnd = FindWindow(Nothing, "Application to Find")
_AutomationElementA = AutomationElement.FromHandle(ParenthWnd)
If _AutomationElementA Is Nothing Then  
NotifyIcon1.BalloonTipIcon = ToolTipIcon.Error
NotifyIcon1.BalloonTipText = "Couldn't Locate Parent Window."
NotifyIcon1.Visible = True
NotifyIcon1.ShowBalloonTip(3000)
Exit Sub
End If
' MDI Client Stuff
' I used ClassNameProperty but other conditions are available
propCondition = New PropertyCondition(AutomationElement.ClassNameProperty, "WindowsForms10.MDICLIENT.app.0.34f5582_r7_ad1", PropertyConditionFlags.IgnoreCase)
_AutomationElementB = _AutomationElementA.FindFirst(TreeScope.Element Or TreeScope.Children, propCondition)    
If _AutomationElementB Is Nothing Then
NotifyIcon1.BalloonTipIcon = ToolTipIcon.Warning
NotifyIcon1.BalloonTipText = "Application warning MDIClient not Available!"
NotifyIcon1.Visible = True
NotifyIcon1.ShowBalloonTip(3000)
Exit Sub
End If  
' Final Stage Stuff Locate Window Containing Class with Caption   
propCondition = New PropertyCondition(AutomationElement.ClassNameProperty, "WindowsForms10.Window.8.app.0.34f5582_r7_ad1", PropertyConditionFlags.IgnoreCase)
_AutomationElementC = _AutomationElementB.FindFirst(TreeScope.Element Or TreeScope.Children, propCondition)
If _AutomationElementC Is Nothing Then
NotifyIcon1.BalloonTipIcon = ToolTipIcon.Warning
NotifyIcon1.BalloonTipText = "Automation warning, MDI Details are open."
NotifyIcon1.Visible = True
NotifyIcon1.ShowBalloonTip(3000)
Exit Sub
End If
Caption = _AutomationElementC.Current.Name  
' If needed you can now parse/strip any data needed from the Caption text.
' I had other processes here but could not include in the post.
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub