IL2CPP Callbacks In UWP

Hi, when using the .Net scripting backend its possible to pass a reference back from the UWP side to the Unity Side. For example we pass a reference to the SwapChainPanel like so from MainPage.xaml.cs

CI.WSANative.Device.WSANativeProgressControl.Configure(GetSwapChainPanel());

With the depreciation of the .Net scripting backend looming we are looking for a way to do this in IL2CPP, but haven't been able to find a way.

Does anyone have any ideas?

Thanks

 

This looks like a pretty serious feature gap in IL2CPP that hopefully will block fully deprecating the .NET runtime until there's a way to do this. Did you file a feedback item? I'll upvote it if you do.

 

Hi Jackal,

Could you please provide a little more context around your project?

From your description it sounds like your doing this with the .NET back-end and trying to replicate in il2cpp:

- Building a Windows 10 XAML app
- Modifying C# code within the generated VS project
- Passing Windows objects (e.g. SwapChainPanel) from modified C# code into APIs exposed by a plugin

Is there a specific error or problem you're hitting or do you just need general help porting your modified C# code to C++?

The example line of code you gave is not an actual Unity API but instead it appears to be from the Windows Store Native plugin. Are the issues specific to this plugin are you also having issues with Unity specific APIs?

Here are some links to relevant docs and forum posts I found which may be helpful:

https://docs.unity3d.com/Manual/windowsstore-plugins-il2cpp.html
https://forum.unity.com/threads/solved-xamlunityconnection-in-il2cpp-xaml-c-il2cpp.495345/
https://forum.unity.com/threads/uwp-get-swapchainpanel-grid-in-il2cpp-xaml-build.502176/

 

Hi @timke, you're correct yes we are trying to replicate the .Net code we have into IL2CPP.

I'm the developer of the Windows Store Native plugin and we have a scenario where we need to pass the SwapChainPanel from the generated vs project into our plugin code on the Unity side.

With the .Net scripting backend this is very simple as you can call your Unity code from the generated solution. I can't find a way to do this in IL2CPP as the code has obviously been converted to C++.

Example as we have in .Net at the moment:

Unity side we have a function

Code (CSharp):

1. public void SetSwapChain(SwapChainPanel swapChainPanel)
2. {
3.     // Do something with swapChainPanel
4. }

From the generated solution we can call the above function from MainPage.xml.cs

Code (CSharp):

1. SetSwapChain(GetSwapChainPanel());

One of those links you posted may have the answer.

 

From the generated code how do I cast the

"Windows::UI::Xaml::Controls::SwapChainPanel ^" to "IInspectable *"

and on the Unity side how do I reference IInspectable? I saw in another example something like the below but for me UnmanagedType doesn't have the IInspectable value.

[MarshalAs(UnmanagedType.IInspectable)]

 

Thanks look like its working.

Slightly off topic but when compiling against IL2CPP for Window Universal 10 should I be able to use System.Net.Http.HttpClient? The build fails every time even when the code is inside

#if (ENABLE_IL2CPP && UNITY_WSA_10_0)
#endif

Api Compat Level is 4.0

tried scripting runtime version at 3.5 and 4.x but neither work (Unity 2018.2)

 

@Tautvydas-Zilys It complains about HttpClient and anything else in the System.Net.Http namespace not exisiting.

Works fine in the .Net build though

 

@Tautvydas-Zilys Interestingly that builds ok. Edit - it builds but seems to throw an invalid pointer exception in the native code when running, appears to be in the socket implementation.

Since this is part of a plugin though I'm looking for more backwards compatibility.

Surely an api compat level of .Net 4.x should be enough since HttpClient was added with .Net 4? The unity docs even state that it gives you access to the full .net 4 framework.

On the above solution for the SwapChainPanel I get the error "Unable to marshal type Windows.UI.Xaml.Controls.SwapChainPanel" when I call GetSwapChainPanel()

Thanks for your help so far

 

@Tautvydas-Zilys Ok so I've built the winmd + dll and added them to the Unity project.

Set the following properties on them

- Include Platforms - WSAPlayer
- SDK - UWP
- Scripting Backend - IL2CPP

- DLL set to x86

But visual studio fails to resolve the class / namespace so I can't call HelloWorld.WSACommonBridge.GetSwapChainPanel() from the Unity side. Any ideas?

Code

Code (CSharp):

1. #pragma once
2.  
3. namespace HelloWorld
4. {
5.     public ref class WSACommonBridge sealed
6.     {
7.     public:
8.         static Windows::UI::Xaml::Controls::SwapChainPanel^ GetSwapChainPanel();
9.         static void SetSwapChainPanel(Windows::UI::Xaml::Controls::SwapChainPanel^ panel);
10.     private:
11.         WSACommonBridge();
12.         static Windows::UI::Xaml::Controls::SwapChainPanel^ _swapChainPanel;
13.     };
14.  
15.     Windows::UI::Xaml::Controls::SwapChainPanel^ WSACommonBridge::_swapChainPanel;
16.  
17.     Windows::UI::Xaml::Controls::SwapChainPanel^ WSACommonBridge::GetSwapChainPanel()
18.     {
19.         return _swapChainPanel;
20.     }
21.  
22.     void WSACommonBridge::SetSwapChainPanel(Windows::UI::Xaml::Controls::SwapChainPanel^ panel)
23.     {
24.         _swapChainPanel = panel;
25.     }
26. }

 

No error message other than the type / namespace declared in the winmd file is not found when you build

 

Hey, I don't know if this is off topic.
Can somebody help me help me to create a webview Plugin for UWP so that I can display web pages in my application?
PS: Already tried out Wwebview asset it uses a dated API and the website I am planning to load is not supported in it.

 

Just wanted to say that I followed the procedure here and was able to pass data between *.xaml.cpp and my unity code. Thanks!