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Cannot use System.Windows.Forms in preview7

See original GitHub issue

Cannot use `System.Windows.Forms` in `3.0-preview7`

When upgrading from 3.0 preview6 to 3.0-preview7 I get stuck with:

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

General

I realised that the error was coming from the version of dotnet Core after uninstalling ALL available SDKs but the 3.0-preview6 version. I then executed dotnet --version and realised it was still using 3.0-preview7 which made no sense.

This makes me think the uninstaller must also be broken.

Issue Analytics

State:
Created 4 years ago
Comments:11 (3 by maintainers)

Top GitHub Comments

1reaction

RussKiecommented, Jul 29, 2019

<UseWPF>true</UseWPF>

Your project was targeting WPF stack. To target WinForms (or more officially Windows Forms) you need to use <UseWindowsForms>true</UseWindowsForms> as @weltkante suggested.

AFAIK you can target both stacks simultaneously too, e.g. use both switches:

<UseWindowsForms>true</UseWindowsForms>
<UseWPF>true</UseWPF>

1reaction

weltkantecommented, Jul 29, 2019

Do you have a <UseWindowsForms>true</UseWindowsForms> in the project file?

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