I have a problem with a solution that I'm trying to develope. This is my scenario:
I have a VB6 application and I would call from this application some WPF windows. I've used the Interop Form Library to define a WinForm like a bridge from VB6 to WPF. The Interop WinForm exposes the methods to start and shutdown the wpf application.
To do that, in the WPF Application I've defined an helper like this:
Public Class StartApplicationHelper
Public Shared Property IsReady As Boolean = False
Public Shared Event NotifyEvent As ValueEnterEventHandler
Public Shared Sub Start()
If System.Windows.Application.Current Is Nothing Then
Try
Dim myApp As Application = New Application
myApp.ShutdownMode = ShutdownMode.OnExplicitShutdown
myApp.InitializeComponent()
IsReady= True
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End If
End Sub
Public Shared Sub Shutdown()
If System.Windows.Application.Current IsNot Nothing Then
System.Windows.Application.Current.Shutdown()
IsReady = False
End If
End Sub
Public Shared Sub DispatchEvent(ByVal eve As String)
If IsReady Then EventDispatcherService.DispatchEvent(eve, New EventDispatcherDataChildWin(String.Empty, Nothing, Nothing, False))
End Sub
Public Shared Sub DispatchResult(ByVal res As Object)
RaiseEvent NotifyEvent(Nothing, New ValueEnterEventArgs(res))
End Sub
End Class
the method DispatchEvent manage the execute of specific event like the opening of an application window.
For example, on winform I've wrote this statements:
MyWpfApp.StartApplicationHelper.Start()
Do While MyWpfApp.StartApplicationHelper.IsReady = False
System.Windows.Forms.Application.DoEvents()
Loop
MyWpfApp.StartApplicationHelper.DispatchEvent("OpenWin1")
in this way I can define an InteropFormMethod to open wpf window from VB6 across the Interop WinForm.
This solution seems work but I have a problem with a particular use case where the wpf application are stopped (shutdown) and then restarted (start). This is the displayed error message: "Cannot create more than one System.Windows.Application instance in the same AppDomain".
I'm trying to modify my helper to manage this case but I still have not found a solution. I would clean the AppDomain to restart wpf application.
How can I do? Can you help me?
LukePet, here is another related question: WPF used within a WinForms application, where to put Application resources?
Perhaps it gives you all the help you need.
The easiest option is just to keep the WPF application "running":
When you want to close the WPF app just close all the open WPF window and do any cleanup you want but don't call Shutdown.
Later, when the WPF part is "restarted" just open the main window without reinitializing the application.
Your other option is running the WPF app in another AppDomain and loading and unloading it when starting/stopping, this is more complicated, makes communication between the WPF part and the rest of the app difficult and, in my opinion, not worth it in this case.
Related
I have a windows form application.
I want to get all of form that application has, but i just found about the function Application.OpenForms.
This function return all of forms are opening.
But I want to get all of forms in that application.
Is there any functions to get but not add to FormsColection for new Form created like this solution https://support.microsoft.com/en-us/kb/815707 ?
Thank you!
"All of the forms that an application has" typically would mean using reflection for all of the types in the assembly that inherit from the Windows.Forms.Form class.
The Application.OpenForms only tracks forms that are opened, not necessarily those that have been instantiated and not opened.
What you really need to do is track all of the forms when the form objects are instantiated. See code below:
Public Class Form1
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Globals.InstantiatedForms.Add(Me)
End Sub
End Class
Public Module Globals
Public InstantiatedForms As New List(Of Windows.Forms.Form)
End Module
I am trying to create an instance of Internet Explorer from a WPF application, load a saved local file, and do some further processing once the file is loaded. However, although the file is visible in the Internet Explorer window, the DocumentComplete event never fires:
'static field
Dim iex As ShDocVw.InternetExplorer
Public Sub DoStuff()
Dim path = "c:\test.htm"
iex = New SHDocVw.InternetExplorer
iex.Visible = True
AddHandler iex.DocumentComplete, Sub(o As Object, ByRef url As Object)
'This code is never executed
Dim i = 5
End Sub
iex.Navigate2(path)
End Sub
When I navigate to a non-local URL (e.g. http://www.google.com) the DocumentComplete event does fire.
The same behavior exists for the NavigateComplete2 event.
I tried using a class member method instead of a lambda expression (maybe the lambda expression is going out of scope once the method exits?) using both AddressOf and Handles, but that didn't help.
What do I have to do to have the DocumentComplete event fire?
(NB: The page has no frames.)
Update
This code is being used in a class library, and I therefore cannot use the WebBrowser control, as it cannot be instantiated in code.
As SimonMourier points out in the comments, a WebBrowser can be instantiated in code:
Dim wb = New WebBrowser
AddHandler wb.LoadCompleted, Sub(s, e)
Dim i = 5
End Sub
wb.Navigate(path)
Although the LoadCompleted event still doesn't fire, the Navigated event does, and it appears to be sufficient for my purposes. (Apparently the WebBrowser has to be visible in order for LoadCompleted to fire -- see here and here -- and since I am not using the WebBrowser in the context of a window, I don't think this is even possible in my case.)
You should use the out-of-the-box standard WebBrowser Control that ships with WPF (there is another one for Winforms apps). It has all the basic events directly supported.
Should you miss some Winforms feature like IsWebBrowserContextMenuEnabled or ScriptErrorsSuppressed, I suggest you refer to my answer in this question on SO: How to deactivate "right click" on WPF Webbrowser Control?
You only need interop in these special cases or if you need to get ahold on the native underlying IE's Document Object Model (DOM), interfaces like IHTMLDocument2, etc.
Instead of using ShDocVw.InternetExplorer you can use WebBrowser control provided by WPF:
<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">
<Grid>
<WebBrowser x:Name="webBrowser" Visibility="Visible" />
</Grid>
</Window>
Class MainWindow
Public Sub DoStuff()
Dim path = New Uri("c:\test.htm")
AddHandler webBrowser.LoadCompleted, Sub(sender As Object, e As System.Windows.Navigation.NavigationEventArgs)
Dim i = 5
End Sub
webBrowser.Navigate(path)
End Sub
Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
DoStuff()
End Sub
End Class
There is no need to use WebBrowser Control to get this issue resolved.
I have also faced this issue and it happens due to the access privileges.
Run your application with Admin privileges and it will be fine.
To debug try running your Visual Studio as Administrator and then test, The DocumentComplete event will be fired.
Update1:
In case of non-admin application if you can manage to get the internet explorer started with Admin privileges then also you can work with it using your non-admin application.
Simple start a Internet Explorer process with admin privileges.
Then you can hook it using this code
For Each IE As InternetExplorer In New SHDocVw.ShellWindows
If IE.FullName.ToLower.Contains("iexplore") And IE.LocationURL <> "" Then
'Capture IE here
End If
Next
I have a WPF application with form that has a textbox named "txtStatusWindow". I also have a vb.net class handed to me by a co-worker that needs to be called and executed by the code in my application code-behind. My co-worker insists that I will need to use common .net events to update the textbox on my form.
The separate vb.net class:
Public Class globalclass
Public Event txtStatusWindow(ByVal Text As String)
Public Sub InitializeProgram()
RaiseEvent txtStatusWindow("Updating something.")
System.Threading.Thread.Sleep(2000)
RaiseEvent txtStatusWindow("Updating something else.")
System.Threading.Thread.Sleep(2000)
RaiseEvent txtStatusWindow("Updating something other than else.")
System.Threading.Thread.Sleep(2000)
RaiseEvent txtStatusWindow("Updating something other than the else stuff.")
System.Threading.Thread.Sleep(2000)
End Sub
End Class
I need to be able to call the sub "InitializeProgram()" from my code-behind, and it needs to be able to update "txtStatusWindow.text" as it runs.
I told him that the updating of the text box can be done with data-binding, but I don't know how to integrate a separate class like this into my project, how to call methods in it, or how to cause it to update my text blocks through data binding.
I also suggested that the methods in this class aren't optimal for connecting to the WPF project anyway, but he just wrote it as an example to discover how to connect the two projects.
Eventually, I will need to integrate classes like these that will be running separate threads to update their data from a dynamic source, and cause many controls to update in my application.
So far, the only way we have been able to get this to work from my code-behind is this:
Partial Public Class SplashScreen
Dim NewText as String
Public WithEvents Globals As globalclass = New globalclass
Public Delegate Sub StringDelegate(ByVal Text As String)
Public SplashText As String
Public Sub New()
MyBase.New()
Me.InitializeComponent()
Me.Show()
Globals.InitializeProgram()
End Sub
Public Sub UpdateSplashscreenHandler(ByVal Text As String) Handles Globals.UpdateSplashScreen
StatusWindowText.Text = Text
End Sub
Notwithstanding the fact that the WPF screen "freezes" until the "globalclass InitializeProgram" method completes (txtStatusWindow.Text does not update while sub without using the esoteric "refresh" extension...), I fully believe we are going about this the wrong way.
There are precious few examples out there concerning the integration and then binding to objects in existing code. Thanks for examining our little quandary.
If this status window is in XAML and the status window is a UserControl, then add a StatusText dependency property to the status window. Then, in the XAML you can bind to the value of that property with something like:
<UserControl x:Name="MyStatusWindow" ...>
<TextBlock Text="{Binding Path=StatusText, ElementName=MyStatusWindow}" />
</UserControl>
Then, from your event, just update the value of that StatusText property.
(Is that even close to what you were asking?)
Also, about that freezing: Instead of doing that updating in the constructor of that class, you might want to do it from the Loaded event of that control. It will still be freezing, though, unless you move it to a separate thread. Right now, that's happening on the same thread that the UI message pump is running on. This is the Dispatcher for that UI.
I got my hands om MEF for a week now and I am trying to build up a WPF application that loads imported controls from MEF.
I created a WPF application project and removed the default window and application start up URI. Then I handled the application startup event to compose the application:
public partial class App : Application, IPartImportsSatisfiedNotification
{
{...}
private void App_Startup(object sender, StartupEventArgs e)
{
this.Compose();
}
public void Compose()
{
try
{
globalCatalog.Catalogs.Add(new DirectoryCatalog(extensionsDirectoryPath));
CompositionContainer container = new CompositionContainer(globalCatalog);
container.ComposeParts(this);
}
catch (Exception ex)
{
// Do something
}
}
{...}
}
Actually, when debugging and watching objects after imports are satisfied, everything has hierarchically composed fine like I wanted. But when I try to show up the MainWindow of the application an exception is thrown on MainWindow.Show() call:
"Specified element is already the logical child of another element. Disconnect it first."
Though my code in OnImportsSatisfied method seems fine as it is working when not using MEF mecanism:
public void OnImportsSatisfied()
{
Window mainWindow = new Window();
mainWindow.Content = this.importedControl;
this.MainWindow = mainWindow;
this.MainWindow.Show();
}
I insist on the fact that this works perfectly when not importing controls with MEF. What is surprising is that this code does not work too:
Window mainWindow = new Window();
//mainWindow.Content = this.importedControl;
this.MainWindow = mainWindow;
this.MainWindow.Show();
So I suspect that ComposeParts is doing a bit more than what it says as it is the only member acting on my actual application instance.
Hope someone can help me (Glenn?).
Thanks.
Edit:
I discovered that when I remove the IPartImportsSatisfiedNotification interface from my parts, no exception is thrown and the window shows up. But of course the window is empty as I need this OnImportsSatisfied method to set the DataContext of the window to its associated imported view model.
The sample applications of the WPF Application Framework (WAF) show how to use MEF within a WPF application.
I finally discovered that I was importing my WPF user controls by using the default ImportAttribute constructor, which in fact will make a shared instance of the class if the creation policy is not specified during export. And as many of my controls were implementing the same interface and I was binding them in my views, I was actually trying to add this shared user control instance to different visual elements, which is not permited by WPF (and so the exception).
I marked my imports using the RequiredCreationPolicy set to NonShared and everything got back in order! That was all about learning MEF...
I have a WPF dll that contains a number of Window classes and exposes methods that display those windows.
I also have a separate WinForms project that is calling one of those methods in the WPF project inside the DoWork method of a BackgroundWorker component.
On the line of code that instantiates a WPF Window, I get the following runtime error:
The calling thread must be STA, because many UI components require this.
A google search let me to this discussion. (Turns out Jon Skeet answers questions on other sites in addition to Stack Overflow!) He linked to this article, which states
The BackgroundWorker component works well with WPF ...
That article also mentions using the DispatcherObject class, but I don't understand how to make that work and I would rather just continue using my BackgroundWorker component.
As a test case, I came up with the following code to reproduce the error. In the WPF class library, here is the code in Window1.xaml.vb
Partial Public Class Window1
Public Shared Function ShowMe() As Boolean?
Dim w = New Window1 'Error appears on this line.
Return w.ShowDialog()
End Function
End Class
In the WinForms application, here is the code in Form1.vb
Imports System.ComponentModel
Public Class Form1
Private WithEvents worker As BackgroundWorker
Private Sub doWord(ByVal sender As Object, ByVal e As DoWorkEventArgs) Handles worker.DoWork
WpfLibrary.Window1.ShowMe()
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
worker = New BackgroundWorker
worker.RunWorkerAsync()
End Sub
End Class
Even when the BackgroundWorker component is placed in Window1.xaml.vb itself, the same error occurs. So, is that article wrong and I can't really use a BackgroundWorker with WPF? Or is there something else I need to do to get it to work?
If the BackgroundWorker won't work, then how would I replace the code in Form1.vb above to use a Dispatcher instead?
You can use a background worker with WPF, that's not your problem.
Your problem is that you can't perform any task that updates the UI from outside of the main UI thread in either a winform or WPF application and the BackgroundWorker's DoWork method is running in a different thread.
Therefore you must open the new window outside of the BackgroundWorker's background thread, either before you start the BackgroundWorker, or in its RunWorkerCompleted event.
Without knowing the code that surrounds the call to open the window it is difficult for me to advise further, but I hope that points you in the right direction.
Your worker could also create its own thread, mark that thread as STA, and then call Thread.Join() to wait for it to terminate. You would then be able to create and show the window on your new thread (although note that no other thread will be able to interact with it without using the Dispatcher).
Example in C#:
Thread workerThread = new Thread(ShowMyWindow);
workerThread.SetApartmentState(ApartmentState.STA);
workerThread.Start();
workerThread.Join();
And then:
private void ShowMyWindow()
{
WpfLibrary.Window1.ShowMe()
}