.NET Core 2.2 Assembly System.Windows.Forms missing

Question

I want to migrate my project in .NET Framework 4.0 to .NET Core 2.2. But I have an error in my program execution.

My project wants to load a .dll with the Assembly class, it's working fine with .NET Framework 4.0 but not with .NET Core 2.2. It's throwing a n exception:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.IO.FileNotFoundException: Could not load file or assembly 'System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

using System.Reflection; // Assembly class

var pathToDll = "../../../../";
var asm = Assembly.LoadFrom(pathToDll);

var callingProgObject = asm.GetType("RandomType.CallingProg");
MethodInfo method = callingProgObject.GetMethod("MethodInDll");

var input = new InputForDll();
method.Invoke(callingProgObject, new object[] {input}); // <-------- error

I need to import one package compatible for .NET Core 2.2 similar to System.Windows.Forms of .NET Framework 4.0?

My NuGet packages installed in Solution:

Not duplicate of How to use System.Windows.Forms in .NET Core class library

Did you replace the real values with RandomType and MethodInDll ? Because they are rather crucial here. And what part of your code is calling this (and why) ? — bommelding, Oct 25 '18 at 10:38
Winforms isn't supported in .NET Core 2.2. It might be supported in .NET Core 3 though. [link](https://blogs.msdn.microsoft.com/dotnet/2018/05/07/net-core-3-and-support-for-windows-desktop-applications/) — James Cockayne, Oct 25 '18 at 10:48
Primary focus for .netcore was to make porting to Linux and macOS easy. That can't work for Winforms, those OSes are far too different. I haven't see a lot of praise for Mono's attempt to do this. Consider Xamarin if you need a GUI that runs on .netcore. Or wait until .netcore 3 gets stable, if porting is not important, that will take a while. No rush, .netframework is just fine. — Hans Passant, Oct 25 '18 at 11:59

score 3 · Accepted Answer · answered Oct 25 '18 at 11:11

3

There is no Windows Forms (or WPF) for .NET Core.

What you want is not possible

^{(but might be possible with a defined subset of .NET Core with the next major version)}

If you list your requirements, maybe people can suggest another way to do it, but it won't be Windows Forms.

answered Oct 25 '18 at 11:11

nvoigt

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I don't think the OP wants to run WinForms, it's obviously an ASP.NET Core project. With some obscure component still wanting to use something from Windows.Forms, like maybe `Color` or `Rect` – bommelding Oct 25 '18 at 12:09
3

Then why did you accept this answer? That sends the wrong message. – bommelding Oct 26 '18 at 11:43

score 2 · Answer 2 · answered Oct 25 '18 at 11:12

2

Currently the Windows.Forms is not supported on .NET core.

You can refer to this answer for alternate ways of creating GUI in .NET core.

answered Oct 25 '18 at 11:12

B45i

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Eimaaa · Answer 3 · 2022-10-06T13:23:31.880

0

Just add

<UseWindowsForms>true</UseWindowsForms>

to your .csproj file

edited Oct 06 '22 at 13:23

answered Oct 06 '22 at 13:22

Eimaaa

1
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Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Oct 10 '22 at 11:50

.NET Core 2.2 Assembly System.Windows.Forms missing

3 Answers3

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