WPF App Using new csproj format

Question

I am experimenting with migrating a WPF project, defined using the old csproj format, to the new format under VS 2017.

I was able to get most of the way to a successful build using information I found at How-to migrate Wpf projects to the new VS2017 format .

But I'm stuck at getting past this error:

error CS5001: Program does not contain a static 'Main' method suitable for an entry point

My new-style csproj file is as follows:

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

  <PropertyGroup>
    <LanguageTargets>$(MSBuildExtensionsPath)\$(VisualStudioVersion)\Bin\Microsoft.CSharp.targets</LanguageTargets>
    <OutputType>winexe</OutputType>
    <TargetFramework>net47</TargetFramework>
    <ApplicationIcon />
    <OutputTypeEx>winexe</OutputTypeEx>
    <StartupObject />
  </PropertyGroup>

  <ItemGroup>
    <EmbeddedResource Update="Properties\Resources.resx" Generator="ResXFileCodeGenerator" LastGenOutput="Resources.Designer.cs" />
    <Compile Update="Properties\Resources.Designer.cs" DesignTime="True" AutoGen="True" DependentUpon="Resources.resx" />
    <Compile Update="Settings.Designer.cs" AutoGen="True" DependentUpon="Settings.settings" />
    <None Update="Settings.settings" LastGenOutput="Settings.Designer.cs" Generator="SettingsSingleFileGenerator" />

    <Page Include="**\*.xaml" SubType="Designer" Generator="MSBuild:Compile" />
    <Compile Update="**\*.xaml.cs" SubType="Designer" DependentUpon="%(Filename)" />

    <Resource Include="assets\*.*" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Autofac" Version="4.6.0" />
    <PackageReference Include="Autofac.Extras.CommonServiceLocator" Version="4.0.0" />
    <PackageReference Include="Extended.Wpf.Toolkit" Version="3.0.0" />
    <PackageReference Include="Hardcodet.NotifyIcon.Wpf" Version="1.0.8" />
    <PackageReference Include="MaterialDesignColors" Version="1.1.3" />
    <PackageReference Include="MaterialDesignThemes" Version="2.3.0.823" />
    <PackageReference Include="MvvmLightLibs" Version="5.3.0" />
    <PackageReference Include="Serilog" Version="2.4.0" />
    <PackageReference Include="Serilog.Sinks.RollingFile" Version="3.3.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\..\WPFUtilities\J4JUI\J4JUI.csproj" />
  </ItemGroup>

  <ItemGroup>
    <Reference Include="System.ComponentModel.DataAnnotations" />
  </ItemGroup>

  <Import Project="$(MSBuildSDKExtrasTargets)" Condition="Exists('$(MSBuildSDKExtrasTargets)')" />
</Project>

How do I configure the csproj file so that entry point gets built?

Update

Based on the tip about ApplicationDefinition I was able to get the project to compile. I could not set ApplicationDefinition in the BuildAction -- it was not one of the choices -- but had to edit the csproj file manually to include it. Here's the working version:

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

  <PropertyGroup>
    <LanguageTargets>$(MSBuildExtensionsPath)\$(VisualStudioVersion)\Bin\Microsoft.CSharp.targets</LanguageTargets>
    <OutputType>winexe</OutputType>
    <TargetFramework>net47</TargetFramework>
    <ApplicationIcon />
    <OutputTypeEx>winexe</OutputTypeEx>
    <StartupObject />
  </PropertyGroup>

  <ItemGroup>
    <EmbeddedResource Update="Properties\Resources.resx" Generator="ResXFileCodeGenerator" LastGenOutput="Resources.Designer.cs" />
    <Compile Update="Properties\Resources.Designer.cs" DesignTime="True" AutoGen="True" DependentUpon="Resources.resx" />
    <Compile Update="Settings.Designer.cs" AutoGen="True" DependentUpon="Settings.settings" />
    <None Update="Settings.settings" LastGenOutput="Settings.Designer.cs" Generator="SettingsSingleFileGenerator" />

    <Page Include="**\*.xaml" SubType="Designer" Generator="MSBuild:Compile" Exclude="App.xaml" />
    <Compile Update="**\*.xaml.cs" SubType="Designer" DependentUpon="%(Filename)" />

    <Resource Include="assets\*.*" />

    <ApplicationDefinition Include="App.xaml">
      <Generator>MsBuild:Compile</Generator>
      <SubType>Designer</SubType>
    </ApplicationDefinition>

  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Autofac" Version="4.6.0" />
    <PackageReference Include="Autofac.Extras.CommonServiceLocator" Version="4.0.0" />
    <PackageReference Include="Extended.Wpf.Toolkit" Version="3.0.0" />
    <PackageReference Include="Hardcodet.NotifyIcon.Wpf" Version="1.0.8" />
    <PackageReference Include="MaterialDesignColors" Version="1.1.3" />
    <PackageReference Include="MaterialDesignThemes" Version="2.3.0.823" />
    <PackageReference Include="MvvmLightLibs" Version="5.3.0" />
    <PackageReference Include="Serilog" Version="2.4.0" />
    <PackageReference Include="Serilog.Sinks.RollingFile" Version="3.3.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\..\WPFUtilities\J4JUI\J4JUI.csproj" />
  </ItemGroup>

  <ItemGroup>
    <Reference Include="System.ComponentModel.DataAnnotations" />
  </ItemGroup>

  <Import Project="$(MSBuildSDKExtrasTargets)" Condition="Exists('$(MSBuildSDKExtrasTargets)')" />
</Project>

Note also the Exclude filter on the directive. It's necessary to keep MSBuild from attempting to compile App.xaml.cs twice.

Answer 1

You need to set the Build Action of App.xaml to ApplicationDefinition. The result is the following item in your csproj file:

<ApplicationDefinition Include="App.xaml">
  <Generator>MSBuild:Compile</Generator>
  <SubType>Designer</SubType>
</ApplicationDefinition>

Answer 2

For people using this example to migrate to Visual studio 2019. Use the following for LanguageTargets. The current LanguageTargets example is specifically for 2017 and will not work under 2019. (Due to a new file location)

<LanguageTargets>$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Bin\Microsoft.CSharp.targets</LanguageTargets>