I get some errors when I want to replace Xamarin.Forms with Microsoft.Maui.Essentials. Can I use Microsoft.Maui.Essentials instead?

Question

I get some errors when I want to replace Xamarin.Forms with Microsoft.Maui.Essentials. Can I use Microsoft.Maui.Essentials instead?

Kim Strasser 1,321

I use the MonoGame 3.8.1.303 template to create my Android project, not the MAUI template in Visual Studio. And I set UseMauiEssentials to true in my Android csproj file so that I can use Microsoft.Maui.Essentials. But the problem is that I get some errors after removing the NuGet package Xamarin.Forms from my project.

 Xamarin.Forms.Forms.Init(this, bundle);

Error CS0234: The type or namespace name 'Forms' does not exist in the namespace 'Xamarin' (are you missing an assembly reference?)

 if (Xamarin.Forms.Device.RuntimePlatform == Xamarin.Forms.Device.iOS)

Error CS0234: The type or namespace name 'Forms' does not exist in the namespace 'Xamarin' (are you missing an assembly reference?)

CurrentAppVersion = AppInfo.VersionString;  
CurrentAppBuild = AppInfo.BuildString;

Error CS0103: The name 'AppInfo' does not exist in the current context

I use Target Android version 13.0 (API level 33). Is it still necessary to use Xamarin.Forms or can I use Microsoft.Maui.Essentials to solve these errors?

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Reputation points Microsoft External Staff

2023-01-02T03:16:04.14+00:00
I'm not clear that how you use the MonoGame 3.8.1.303 template to create an Android project, and I'm not sure if it is a MAUI project (or .NET Android project) or a Xamarin project. Besides, I'm not sure if you want to bring your Xamarin.Forms project to .NET MAUI. Can you share a screenshot of your project? For the first Xamarin.Forms.Forms.Init(this, bundle) error, in which method is this line of code?

The Xamarin.Essentials classes are included in MAUI proper rather than being pulled out into a separate library, you do not need to use Microsoft.Maui.Essentials.(If your project is for Xamarin, you can use Xamarin.Essentials ).

For the if (Xamarin.Forms.Device.RuntimePlatform == Xamarin.Forms.Device.iOS) error, you can try to use conditional compilation in MAUI:

#if ANDROID ...... #elif IOS ...... #endif

And you said you create an Android project, it might always be Android without having to identify which platform.
Fo the third AppInfo error, you can check App Information - .NET MAUI | Microsoft Learn and Xamarin.Essentials: Device Information - Xamarin | Microsoft Learn. And it will use Microsoft.Maui.ApplicationModel namespace in MAUI.
Kim Strasser 1,321 Reputation points

2023-01-02T12:34:15.777+00:00
I'm not clear that how you use the MonoGame 3.8.1.303 template to create an Android project, and I'm not sure if it is a MAUI project (or .NET Android project) or a Xamarin project.

I have a MonoGame Android project, a MonoGame iOS project and a MonoGame project for shared game code in my solution. But currently I'm only testing the Android project on my device.
I have only added UseMauiEssentials to my csproj files:

My Android csproj:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0-android</TargetFramework>
<SupportedOSPlatformVersion>23</SupportedOSPlatformVersion>
<OutputType>Exe</OutputType>
<UseMauiEssentials>true</UseMauiEssentials>

My iOS csproj:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0-ios</TargetFramework>
<OutputType>Exe</OutputType>
<UseMauiEssentials>true</UseMauiEssentials>
<SupportedOSPlatformVersion>15.0</SupportedOSPlatformVersion>

In my Android project I used this code in Activity1.cs when I used Xamarin.Forms and Xamarin.Essentials:

protected override void OnCreate(Bundle bundle) { base.SetTheme(Resource.Style.MainTheme); base.OnCreate(bundle); Xamarin.Forms.Forms.Init(this, bundle); Xamarin.Essentials.Platform.Init(this, bundle);
Kim Strasser 1,321 Reputation points

2023-01-02T12:50:14.37+00:00

I have removed the lines Xamarin.Forms.Forms.Init(this, bundle); and Xamarin.Essentials.Platform.Init(this, bundle); from my code because I have removed the Xamarin NuGet packages. But now I get this new error in the file Xamarin.Android.Common.targets:

/usr/local/share/dotnet/packs/Microsoft.Android.Sdk.Darwin/32.0.476/tools/Xamarin.Android.Common.targets(3,3): Error XALNS7028: System.IO.FileNotFoundException: Could not load assembly 'Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken='. Perhaps it doesn't exist in the Mono for Android profile?

File name: 'Microsoft.Maui.Controls.dll'

Is it necessary to add the file Microsoft.Maui.Controls to my Android project's Frameworks folder?
Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Reputation points Microsoft External Staff

2023-01-03T02:45:02.817+00:00

May I ask why you want to remove Xamarin.Forms? MonoGame 3.8.1.303 template supports Xamarin, and you want to migrate from Xamarin to MAUI, right? Can you try to create an empty MAUI template in Visual Studio and use MonoGame.Framework.Android and MonoGame.Framework.Android NuGet packages?
In addition, if you are using this template ( https://github.com/MonoGame/MonoGame/tree/develop/Templates), you can post at their GitHub source repository for further help.

1 answer

Your answer

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Reputation points Microsoft External Staff

2023-01-02T03:16:04.14+00:00

I'm not clear that how you use the MonoGame 3.8.1.303 template to create an Android project, and I'm not sure if it is a MAUI project (or .NET Android project) or a Xamarin project. Besides, I'm not sure if you want to bring your Xamarin.Forms project to .NET MAUI. Can you share a screenshot of your project? For the first Xamarin.Forms.Forms.Init(this, bundle) error, in which method is this line of code?

The Xamarin.Essentials classes are included in MAUI proper rather than being pulled out into a separate library, you do not need to use Microsoft.Maui.Essentials.(If your project is for Xamarin, you can use Xamarin.Essentials ).

For the if (Xamarin.Forms.Device.RuntimePlatform == Xamarin.Forms.Device.iOS) error, you can try to use conditional compilation in MAUI:

#if ANDROID ...... #elif IOS ...... #endif

And you said you create an Android project, it might always be Android without having to identify which platform.
Fo the third AppInfo error, you can check App Information - .NET MAUI | Microsoft Learn and Xamarin.Essentials: Device Information - Xamarin | Microsoft Learn. And it will use Microsoft.Maui.ApplicationModel namespace in MAUI.
Kim Strasser 1,321 Reputation points

2023-01-02T12:34:15.777+00:00

I'm not clear that how you use the MonoGame 3.8.1.303 template to create an Android project, and I'm not sure if it is a MAUI project (or .NET Android project) or a Xamarin project.

I have a MonoGame Android project, a MonoGame iOS project and a MonoGame project for shared game code in my solution. But currently I'm only testing the Android project on my device.
I have only added UseMauiEssentials to my csproj files:

My Android csproj:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0-android</TargetFramework>
<SupportedOSPlatformVersion>23</SupportedOSPlatformVersion>
<OutputType>Exe</OutputType>
<UseMauiEssentials>true</UseMauiEssentials>

My iOS csproj:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net6.0-ios</TargetFramework>
<OutputType>Exe</OutputType>
<UseMauiEssentials>true</UseMauiEssentials>
<SupportedOSPlatformVersion>15.0</SupportedOSPlatformVersion>

In my Android project I used this code in Activity1.cs when I used Xamarin.Forms and Xamarin.Essentials:

protected override void OnCreate(Bundle bundle) { base.SetTheme(Resource.Style.MainTheme); base.OnCreate(bundle); Xamarin.Forms.Forms.Init(this, bundle); Xamarin.Essentials.Platform.Init(this, bundle);
Kim Strasser 1,321 Reputation points

2023-01-02T12:50:14.37+00:00

I have removed the lines Xamarin.Forms.Forms.Init(this, bundle); and Xamarin.Essentials.Platform.Init(this, bundle); from my code because I have removed the Xamarin NuGet packages. But now I get this new error in the file Xamarin.Android.Common.targets:

/usr/local/share/dotnet/packs/Microsoft.Android.Sdk.Darwin/32.0.476/tools/Xamarin.Android.Common.targets(3,3): Error XALNS7028: System.IO.FileNotFoundException: Could not load assembly 'Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken='. Perhaps it doesn't exist in the Mono for Android profile?

File name: 'Microsoft.Maui.Controls.dll'

Is it necessary to add the file Microsoft.Maui.Controls to my Android project's Frameworks folder?
Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Reputation points Microsoft External Staff

2023-01-03T02:45:02.817+00:00

May I ask why you want to remove Xamarin.Forms? MonoGame 3.8.1.303 template supports Xamarin, and you want to migrate from Xamarin to MAUI, right? Can you try to create an empty MAUI template in Visual Studio and use MonoGame.Framework.Android and MonoGame.Framework.Android NuGet packages?
In addition, if you are using this template ( https://github.com/MonoGame/MonoGame/tree/develop/Templates), you can post at their GitHub source repository for further help.

Answer 1

Kim Strasser 1,321

It works now. I have added UseMaui to my Android csproj file:

<Project Sdk="Microsoft.NET.Sdk">  
  <PropertyGroup>  
    <TargetFramework>net6.0-android33.0</TargetFramework>  
    <SupportedOSPlatformVersion>30.0</SupportedOSPlatformVersion>  
    <OutputType>Exe</OutputType>  
    <UseMaui>true</UseMaui>  
    <UseMauiEssentials>true</UseMauiEssentials>

Then Microsoft.Maui.Controls and Microsoft.Maui.Core are added to my project and I don't get the error System.IO.FileNotFoundException anymore.

Wenyan Zhang (Shanghai Wicresoft Co,.Ltd.) 36,436 Reputation points Microsoft External Staff

2023-01-04T02:00:19.22+00:00

Glad you solved the problem, thanks for your sharing. I converted the comment to an answer so that someone who meets the same issue can refer to it.

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I get some errors when I want to replace Xamarin.Forms with Microsoft.Maui.Essentials. Can I use Microsoft.Maui.Essentials instead?

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