Unable to publish with fulltrustprocess and Multiple instances of UWP app

DotNET Fan 271

UWP experts ,

There are three components here.

Main UWP app with multiple instances supported through package manifest - C# UWP
FullTrustprocess that acts as the appserviceconnection server - C# .NET 8
WAPP Package that bundles UWP app and fulltrustprocess.

When we build it in spite of adding the entry points in package manifests , still it gives publish error.

I have added the desktop4:SupportsMultipleInstances="true" in both package manifest and UWP app manifest

Error DEP0700: Registration of the app failed. [0x80073CF6] AppxManifest.xml(35,10): error 0x80080204: Cannot register the package because EntryPoint must be specified when SupportsMultipleInstances is true.

Package - package manifest

UWP App - package manifest

How to enable MultipleInstances for UWP app in this scenario?

Thanks

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-12T01:36:21.39+00:00

Hello @DotNET Fan ,
I hope you're doing well. Just checking in to see if your issue has been resolved. Please let me know if you need any further assistance.

Thank you.
Roy Li - MSFT 33,501 Reputation points Microsoft Vendor

2024-12-20T02:29:30.2833333+00:00

Hope you've been well. Any updates about this issue?
Adil Rasheed 0 Reputation points

2024-12-20T04:57:23.14+00:00

It seems you're facing issues with publishing due to FullTrustProcess or handling multiple UWP app instances. Ensure your app's manifest and deployment configurations are correctly set, as conflicts here often cause such errors. While troubleshooting this, take a break and check out something fun, like the SimCity BuildIt Mod APK, for a fresh perspective!
Roy Li - MSFT 33,501 Reputation points Microsoft Vendor

2024-12-24T08:31:01.2866667+00:00

Haven't heard from you for a while. Have you solved your issue?

1 answer

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-03T08:01:59.7533333+00:00

Hello @DotNET Fan ,

Welcome to Microsoft Q&A!

According to the document,

Out-of-proc background tasks support multi-instancing. Typically, each new trigger results in a new instance of the background task (although technically speaking multiple background tasks may run in same host process). Nevertheless, a different instance of the background task is created. In-proc background tasks do not support multi-instancing.

In-processs AppService is not supported for multi-instance apps.

It is recommended to use out-of-processs AppService. Disable multi-instance for out-of-proc service. Create a new service for each instance of UWP. Create a static field in the background task class to store the AppService for desktop extension and initialize it when you create AppService from the desktop extension.

Soumya Mahunt shared the solution, you can try it out.

Thank you.

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DotNET Fan 271 Reputation points

2024-12-03T16:48:33.86+00:00

, the fulltrustprocess has the Appservice running and that is a seperate process , so it is out of process right?

UWP App client can have multiple instances and each instance connecting to single server appservice running in the fulltrust process. Why in this scenario publishing fails?

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-04T06:50:21.2033333+00:00

Hello @DotNET Fan ,

the fulltrustprocess has the Appservice running and that is a seperate process , so it is out of process right?

No.

According to the definition of Appservice in the Package.appxmanifest, if you don't use a background task to implement Appservice, it's an in-process Appservice.

DotNET Fan 271 Reputation points

2024-12-05T03:56:17.6066667+00:00

@Junjie Zhu - MSFT so with outofprocess implementation with background Task , each instances of UWP app client will call launchfulltrustprocess and from the fulltrust processes open Appservice server connections that each UWP Appservice client can connect?

Some thing like one to one bi directional connection?

To Summarize , What are the issues with Inproc Appservice?

No Multi-Instance UWP App

First time when a new UWP app instance comes up and call fulltrust process to open appserviceconnection , it triggers background activated in UWP app. If you open a second instance of UWP app and call fulltrust process to open appserviceconnection , it wont trrgger the background actived in UWP app?

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-06T06:22:02.0066667+00:00

Some thing like one to one bi directional connection?

Yes. Store the Appservice of your desktop extension in your Background Task class, you can pass messages from your UWP app instance to the out-of-process Appservice and then from the Appservice to the desktop extension.

it wont trrgger the background actived in UWP app?

No, create a static field in each new background task class to store the Appservice of the desktop extension, each of which points to a separate Appservice.

DotNET Fan 271 Reputation points

2024-12-06T13:56:23.3633333+00:00

@Junjie Zhu - MSFT

I assume that the link that you have provided earlier was about having multiple Appserviceconnections in between UWP app and fulltrustprocess using background task.

What iam referring is about UWP multiple instances. I should be able to open multiple instances of the UWP app . Generally going to start menu and clicking on the app icon multiple times , that would open multiple instances of the UWP app. I was having that added under Applications node . But with the new additions of extensions - one is fulltrust process and the other appservice under Application node and the WAPP package , doesnt allow for publishing even after adding the entry point in package manifest.

<Application Id="App"

Executable="$targetnametoken$.exe"

EntryPoint="$targetentrypoint$"

desktop4:SupportsMultipleInstances="true"

>

<Extensions>

<uap:Extension Category="windows.appService">

<uap:AppService Name="DesktopAppService" />

</uap:Extension>

<desktop:Extension Category="windows.fullTrustProcess" Executable="FullTrust\DesktopProcessor.exe" EntryPoint="Desktop.Program"/>

</Extensions>

Error DEP0700: Registration of the app failed. [0x80073CF6] AppxManifest.xml(35,10): error 0x80080204: Cannot register the package because EntryPoint must be specified when SupportsMultipleInstances is true.

Thanks

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-09T09:21:19.1233333+00:00

Hello @DotNET Fan ,

It is recommended to use out-of-processs AppService, I modified it on the original test project and it worked fine. You need to declare out of process AppService in the UWP project.

UWP project:

<Applications> <Application Id="App" Executable="$targetnametoken$.exe" EntryPoint="FulltrustUWP.App" desktop4:SupportsMultipleInstances="true"> <uap:VisualElements DisplayName="HellowWorld_UWP" Square150x150Logo="Assets\Square150x150Logo.png" Square44x44Logo="Assets\Square44x44Logo.png" Description="FulltrustUWP" BackgroundColor="transparent"> <uap:DefaultTile Wide310x150Logo="Assets\Wide310x150Logo.png"/> <uap:SplashScreen Image="Assets\SplashScreen.png" /> </uap:VisualElements> <Extensions> <uap:Extension Category="windows.appService" EntryPoint="MyAppService.Inventory"> <uap3:AppService Name="com.microsoft.inventory" uap4:SupportsMultipleInstances="true"/> </uap:Extension> </Extensions> </Application> </Applications>

WAPP project:

<Applications> <Application Id="App" Executable="$targetnametoken$.exe" EntryPoint="FulltrustUWP.App" desktop4:SupportsMultipleInstances="true"> <uap:VisualElements DisplayName="DaisyTest" Description="Packages" BackgroundColor="transparent" Square150x150Logo="Images\Square150x150Logo.png" Square44x44Logo="Images\Square44x44Logo.png"> <uap:DefaultTile Wide310x150Logo="Images\Wide310x150Logo.png" /> <uap:SplashScreen Image="Images\SplashScreen.png" /> </uap:VisualElements> <Extensions> <desktop:Extension Category="windows.fullTrustProcess" Executable="WpfApp1\WpfApp1.exe"/> </Extensions> </Application> </Applications>

Thank you.

DotNET Fan 271 Reputation points

2024-12-12T05:30:09.2033333+00:00

@Junjie Zhu - MSFT In my current implemetation, UWP app is the appserviceclient and the fulltrust process is the server and from the fulltrust process it starts a appservice connection initially and the UWP app override void OnBackgroundActivated gets called passing the Appservice connection which is used for the subsequent requests .

So in the out of process Appservice scenario , where should the BackgroundTask implementation be? UWP or the full trust process? Who should open the appservice connection initially?

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-12T09:26:18.51+00:00

I haven't tried your scenario yet, it is recommended to implement background task in Windows Runtime Component, you can use application trigger to trigger background task in UWP.

DotNET Fan 271 Reputation points

2024-12-12T16:51:46.26+00:00

@Junjie Zhu - MSFT My current implementation is based on this ticket .

I did implement the Appservice communication between the fulltrust process and UWP app based on that ticket , but the feature of multiple instances for the app UWP app have taken a fullstop. Logically i'm not able to understand why the appservice communication will get impacted if we have multiple instances of the UWP app and why the publish is failing.

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-16T07:32:02.3166667+00:00

Hello @DotNET Fan ,

I tried your scenario but couldn't find a solution yet.

This seems to be by design, publishing will fail when both appService and SupportsMultipleInstances are defined in the WAPP project, but this is not mentioned in the official documentation of the desktop bridge. The current feasible solution is to move the definition of appService to the UWP project and implement the service in a Windows Runtime Component.

Thank you.

DotNET Fan 271 Reputation points

2024-12-16T15:12:58.2866667+00:00

@Junjie Zhu - MSFT

"The current feasible solution is to move the definition of appService to the UWP project and implement the service in a Windows Runtime Component."

Going with the current scenario of fulltrustprocess and UWP app - ticket

What is the design change here ? Is that i have to swap the implementation? I have to implement the appservice as background task in the fulltrustprocess and open the appservice connection from the UWP? If we move the appservice definition to the UWP project , the appservice connection can't be opened from fulltrust process.

Kindly advise.

Thanks

Junjie Zhu - MSFT 19,751 Reputation points Microsoft Vendor

2024-12-17T09:46:03.1666667+00:00

What is the design change here?

The definition of appService should be in the UWP project and implement the service in a Windows Runtime Component. You can refer to this Create and consume an app service.

Is that i have to swap the implementation? I have to implement the appservice as background task in the fulltrustprocess and open the appservice connection from the UWP? UWP app is the appserviceclient and the fulltrust process is the server and from the fulltrust process it starts a appservice connection initially and the UWP app override void OnBackgroundActivated gets called passing the Appservice connection which is used for the subsequent requests.

I'm in the opposite scenario, fulltrust process WPF as a client, UWP needs to be minimized to activate the background task(the service).

I understand your need, you need UWP to launch a 3rd party exe to transfer files and UWP is your main portal. The current solution is not compatible with your scenario, but there is no better solution as per current publish limitations.
You can try to build a test project first to check if using fulltrust process as a client and background task to implement appservice can meet your needs.
I don't know what your exe is, you can add your exe to WAPP desktop:FullTrustProcess based on my solution and try to start the exe in the fulltrust.exe.

Thank you.
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Unable to publish with fulltrustprocess and Multiple instances of UWP app

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