VS2019 Winforms SDK风格项目，无法添加新表单

Question

VS20019 创建一个以 .net 框架（即 .net 4.7.2）为目标的 Windows 窗体项目作为“旧”样式项目。我已使用Project2015To2017.Migrate2019.Tool 将新创建的项目转换为 SDK 样式。转换后的项目运行正常，但 VS20019 Add/New item 对话框没有显示 Winforms 部分和表单模板。 仍然 VS2017 Add/New item 对话框成功显示 Winforms 部分。就像 VS20019 对“旧”风格的原始项目所做的那样。

我错过了什么？ 转换后的项目：

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net472</TargetFramework>
    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
    <OutputPath>bin\$(Configuration)\</OutputPath>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <DebugType>full</DebugType>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <DebugType>pdbonly</DebugType>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System.Data.DataSetExtensions" />
    <Reference Include="Microsoft.CSharp" />
    <Reference Include="System.Deployment" />
    <Reference Include="System.Net.Http" />
    <Reference Include="System.Windows.Forms" />
  </ItemGroup>
  <ItemGroup>
    <Compile Update="Form1.cs">
      <SubType>Form</SubType>
    </Compile>
    <Compile Update="Form1.Designer.cs">
      <DependentUpon>Form1.cs</DependentUpon>
    </Compile>
    <EmbeddedResource Update="Properties\Resources.resx">
      <Generator>ResXFileCodeGenerator</Generator>
      <LastGenOutput>Resources.Designer.cs</LastGenOutput>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <Compile Update="Properties\Resources.Designer.cs">
      <AutoGen>True</AutoGen>
      <DependentUpon>Resources.resx</DependentUpon>
    </Compile>
    <None Include="Properties\Settings.settings">
      <Generator>SettingsSingleFileGenerator</Generator>
      <LastGenOutput>Settings.Designer.cs</LastGenOutput>
    </None>
    <Compile Update="Properties\Settings.Designer.cs">
      <AutoGen>True</AutoGen>
      <DependentUpon>Settings.settings</DependentUpon>
      <DesignTimeSharedInput>True</DesignTimeSharedInput>
    </Compile>
  </ItemGroup>
</Project>

这是 Windows7 prof x64 上的 VS2019 Community 16.7.1。

Answer 1

这是一个正确的项目文件。注意<UseWindowsForms>true</UseWindowsForms>

<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net472</TargetFramework>
    <UseWindowsForms>true</UseWindowsForms>
 ...