.net8 windows form design view problem.

Question

.net8 windows form design view problem.

Ahmet Haluk UZUNER 20

I am developing Revit addin in Vidual Studio in c++/cli as class library.

Before moving to .net platform everyhing was working fine. But in .net Windows form design views doesnt work. Though when I add form element by code. It compiles and works.

The error is:

The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file: ModelessForm --- The base class 'System.Windows.Forms.Form' could not be loaded. Ensure the assembly has been referenced and that all projects have been built.

Regarding to Windows forms I aded lines below to .vcxproj file

<TargetFramework>net8.0-windows</TargetFramework>

Instances of this error (1)

Hide Call Stack

at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.EnsureDocument(IDesignerSerializationManager manager)

at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)

at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)

at System.ComponentModel.Design.Serialization.BasicDesignerLoader.BeginLoad(IDesignerLoaderHost host)

This is form design view window. 2024-05-04 21 56 39

2024-05-04 21 58 12 The Visual Studio project file is at link below.

https://sendgb.com/U9ePtjK7T5x

Does snybody have any idea how i can resolve that problem?

Minxin Yu 13,501 Reputation points Microsoft External Staff

2024-05-06T05:59:42.3133333+00:00

I am sorry that I cannot access the project link. Can you share a minimal sample without personal privacy via GitHub?
Ahmet Haluk UZUNER 20 Reputation points

2024-05-07T20:43:39.2566667+00:00

Hi.

The link I sent is working. But somehow it has problem with some browsers.
Anyway I added uploaded project to github. The link is https://github.com/halukuzuner/ClassLibrary_net
Minxin Yu 13,501 Reputation points Microsoft External Staff

2024-05-08T02:01:16.1933333+00:00

The .NET Winform desginer currently does not support C++CLI.
Check the issue report: https://github.com/dotnet/winforms/issues/10988

When we started the out-of-process designer we considered CLI/C++ as out of scope. We're focusing on managed languages 100% because we are now using Roslyn under the covers for our codegen.
Ahmet Haluk UZUNER 20 Reputation points

2024-05-08T20:14:23.2666667+00:00
Hi Minxin,

Thanks for your reply.

When I start a project with .net 8 c++ class library visual studio doesnt allow me to add Windows form. The sample windows is at below.

When I add refences which you wrote manually in vcproj file it doesn't compile. Solution explorer view is as shown at below.

I added lines below to vcproj file. It didn't compile.

<ItemGroup>

<Reference Include="System" />

<Reference Include="System.Data" />

<Reference Include="System.Drawing" />

<Reference Include="System.Windows.Forms" />

<Reference Include="System.Xml" />

</ItemGroup>

I replaced references in vcproj file as below. Designer view didn't show the windows form. But the project compiles and works in Revit.

<ItemGroup>

<FrameworkReference Include="Microsoft.WindowsDesktop.App" /> <FrameworkReference Include="Microsoft.WindowsDesktop.App.WPF" /> <FrameworkReference Include="Microsoft.WindowsDesktop.App.WindowsForms" />

</ItemGroup>

Is there any other way to get designer view work?
Minxin Yu 13,501 Reputation points Microsoft External Staff

2024-05-09T01:27:18.4533333+00:00

In your screenshot: CLR ->Winform.

<Reference Include="System.Xml" />

version and public token are needed. Check the txt uploaded in new answer.

Edit vcxproj file and reopen the designer.

it doesn't compile

Becuase System, System.Data, System.Windows.Forms are used in .NET Framework .

use FrameworkReference when building the project.

<FrameworkReference Include="Microsoft.WindowsDesktop.App" />

<FrameworkReference Include="Microsoft.WindowsDesktop.App.WPF" />

<FrameworkReference Include="Microsoft.WindowsDesktop.App.WindowsForms" />

Is there any other way to get designer view work?
As the issue report said,

When we started the out-of-process designer we considered CLI/C++ as out of scope.

Add the condition to include different reference

Accepted answer

1 additional answer

Your answer

Minxin Yu 13,501 Reputation points Microsoft External Staff

2024-05-06T05:59:42.3133333+00:00

I am sorry that I cannot access the project link. Can you share a minimal sample without personal privacy via GitHub?
Ahmet Haluk UZUNER 20 Reputation points

2024-05-07T20:43:39.2566667+00:00

Hi.

The link I sent is working. But somehow it has problem with some browsers.
Anyway I added uploaded project to github. The link is https://github.com/halukuzuner/ClassLibrary_net
Minxin Yu 13,501 Reputation points Microsoft External Staff

2024-05-08T02:01:16.1933333+00:00

The .NET Winform desginer currently does not support C++CLI.
Check the issue report: https://github.com/dotnet/winforms/issues/10988

When we started the out-of-process designer we considered CLI/C++ as out of scope. We're focusing on managed languages 100% because we are now using Roslyn under the covers for our codegen.
Ahmet Haluk UZUNER 20 Reputation points

2024-05-08T20:14:23.2666667+00:00

Hi Minxin,

Thanks for your reply.

When I start a project with .net 8 c++ class library visual studio doesnt allow me to add Windows form. The sample windows is at below.

When I add refences which you wrote manually in vcproj file it doesn't compile. Solution explorer view is as shown at below.

I added lines below to vcproj file. It didn't compile.

<ItemGroup>

<Reference Include="System" />

<Reference Include="System.Data" />

<Reference Include="System.Drawing" />

<Reference Include="System.Windows.Forms" />

<Reference Include="System.Xml" />

</ItemGroup>

I replaced references in vcproj file as below. Designer view didn't show the windows form. But the project compiles and works in Revit.

<ItemGroup>

<FrameworkReference Include="Microsoft.WindowsDesktop.App" /> <FrameworkReference Include="Microsoft.WindowsDesktop.App.WPF" /> <FrameworkReference Include="Microsoft.WindowsDesktop.App.WindowsForms" />

</ItemGroup>

Is there any other way to get designer view work?
Minxin Yu 13,501 Reputation points Microsoft External Staff

2024-05-09T01:27:18.4533333+00:00

In your screenshot: CLR ->Winform.

<Reference Include="System.Xml" />

version and public token are needed. Check the txt uploaded in new answer.

Edit vcxproj file and reopen the designer.

it doesn't compile

Becuase System, System.Data, System.Windows.Forms are used in .NET Framework .

use FrameworkReference when building the project.

<FrameworkReference Include="Microsoft.WindowsDesktop.App" />

<FrameworkReference Include="Microsoft.WindowsDesktop.App.WPF" />

<FrameworkReference Include="Microsoft.WindowsDesktop.App.WindowsForms" />

Is there any other way to get designer view work?
As the issue report said,

When we started the out-of-process designer we considered CLI/C++ as out of scope.

Add the condition to include different reference

Answer 1

Hi,

In Configuration Manager: add new configuration. Such as named design , used to design Winform but not compile it.

User's image Then

Click OK. Then CTRL+S to save the project file.

Add the condition to vcxproj file reference include and framework reference

enter image description here

itemgroup.txt

In Design:

User's image

Since out of process does not support C++CLI. You still need to add controls' code manually, but the controls can be displayed in the designer.

Before building the project, switch to Debug or Release.

Best regards,

Minxin Yu

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Ahmet Haluk UZUNER 20 Reputation points

2024-05-09T07:59:36.59+00:00

It is not complete solution. But It helps. Thanks.

Answer 2

Ahmet Haluk UZUNER 20

Somehow I got it worked.

Sample code is at the link below. c++ .net8.0 and WindowsForms work together.

https://github.com/halukuzuner/RevitAddinCppNet8.0

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.net8 windows form design view problem.

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