Assign window to object via its handle

Question

Just looking for a pointer as I'm struggling to find material online...

Is there a library or reference I can use in VB.NET to assign an arbitrary open window to an object via its handle, such that I can then view the elements & attributes associated with that window? I can identify the handle via Process.MainWindowHandle (i.e. System.Diagnostics.Process.GetProcesses) but how can I then use that handle to "hook" onto the window as an object?

(FYI The window is independent of my application, it's not a form or anything like that - it's just an open window)

All the material I find online is telling me how to get the handle but that's not the issue; I have the handle but I don't know how to use it to "hook" onto the window programmatically?

Would appreciate any pointers anyone could provide!

Thanks

Al

Answer 1

Here is the solution I arrived at, which is working exactly as intended. Cannot claim credit for it as @Jimi gave me all the necessary pointers for me to arrive at this. However, the snippet may be helpful for others trying to navigate UI Automation for the first time, like I was.

Private Sub StartListening()
    Try
        Dim eventHandler As AutomationEventHandler = AddressOf OnWindowOpenOrClose
        Automation.AddAutomationEventHandler(WindowPattern.WindowOpenedEvent, AutomationElement.RootElement, TreeScope.Subtree, eventHandler)

    Catch ex As Exception

    End Try
End Sub

Private Sub StopListening()
    Try
        Automation.RemoveAllEventHandlers()

    Catch ex As Exception

    End Try
End Sub

Private Sub OnWindowOpenOrClose(ByVal src As Object, ByVal e As AutomationEventArgs)

    Dim sourceElement As AutomationElement
    Dim okButton As AutomationElement
    Dim okButtonCondition As Condition
    Dim okButtonInvokePattern As InvokePattern

    Try
        sourceElement = DirectCast(src, AutomationElement)
        If sourceElement IsNot Nothing Then
            If sourceElement.Current.ControlType.Equals(ControlType.Window) AndAlso sourceElement.Current.ClassName = "NUIDialog" AndAlso sourceElement.Current.Name = "<Insert Dialog Name Here As Necessary>" Then
                If e.EventId Is WindowPattern.WindowOpenedEvent Then
                    okButtonCondition = New AndCondition(New PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.Button),
                                                            New PropertyCondition(AutomationElement.NameProperty, "OK"))
                    okButton = sourceElement.FindFirst(TreeScope.Subtree, okButtonCondition)
                    If okButton IsNot Nothing Then
                        okButtonInvokePattern = DirectCast(okButton.GetCurrentPattern(InvokePattern.Pattern), InvokePattern)
                        okButtonInvokePattern.Invoke()
                    End If
                    Return
                End If
            End If
        End If

    Catch
        Return
    End Try

End Sub