WinForm designer in net core 3, no need to create another .net framework project and link files

netcore3-winform-designer

<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFrameworks>net472;netcoreapp3.0</TargetFrameworks>
    <UseWindowsForms>true</UseWindowsForms>
    <LangVersion>7.3</LangVersion>
  </PropertyGroup>
  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' ">
    <Reference Include="System" />
    <Reference Include="System.Core" />
    <Reference Include="System.Xml.Linq" />
    <Reference Include="System.Data.DataSetExtensions" />
    <Reference Include="Microsoft.CSharp" />
    <Reference Include="System.Data" />
    <Reference Include="System.Deployment" />
    <Reference Include="System.Drawing" />
    <Reference Include="System.Net.Http" />
    <Reference Include="System.Windows.Forms" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' ">
    <!-- add From files to here to enable designer -->
    <Compile Update="Forms\Form1.cs">
      <SubType>Form</SubType>
    </Compile>
  </ItemGroup>
</Project>