app.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">
  <!-- This file helps VS Code provide IntelliSense - see https://go.2sxc.org/vscode -->

  <PropertyGroup>
    <!-- Specify the .net Framework you are targeting - this is usually net4.7.2 or net4.8
      https://learn.microsoft.com/en-us/dotnet/standard/frameworks
      - eg "net472", "net48", "net8.0" etc.
      - net472 is the default for DNN 9.8 and earlier but usually net48 works
      - net8.0 is the default for Oqtane 5
    -->
    <TargetFramework>net472</TargetFramework>

    <!-- Specify the default Namespace for code in this specific App -->
    <RootNamespace>ThisApp</RootNamespace>

    <!-- Specify what C# version to use
      https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-version-history
      - eg. "7.3", "8.0" or "12.0" (Oqtane 5+)
    -->
    <LangVersion>8.0</LangVersion>

    <!-- Variable to path where the DLLs are in Dnn
      - This allows you to easily adjust the path if you have a different location
      - For clarity / consistency, we recommend to not end with a slash
      - Below you will use it using $(PathBin)
    -->
    <!-- PathBin for Dnn -->
    <PathBin>..\..\..\..\bin</PathBin>
    <!-- PathBin Oqtane production, just up 3 folders, no bin-subfolder -->
    <!-- <PathBin>..\..\..</PathBin> -->
    <!-- PathBin Oqtane dev/debug, up 3 folders and current build folder -->
    <!-- <PathBin>..\..\..\bin\Debug\net8.0</PathBin> -->
  </PropertyGroup>

  <ItemGroup>
    <!-- Tell Visual Studio & VSCode to respect all ToSic.* DLLs in the root bin folder -->
    <Reference Include="$(PathBin)\ToSic.*.dll" />

    <!-- also add System.Web and DotNetNuke DLLs - useful when creating APIs, but be aware that it may make your code less hybrid -->
    <Reference Include="$(PathBin)\DotNetNuke.dll" />
    <Reference Include="$(PathBin)\DotNetNuke.*.dll" />
    <Reference Include="$(PathBin)\System.Web.Http.dll" />
    <Reference Include="$(PathBin)\System.Web.WebPages.dll" />
    <Reference Include="$(PathBin)\System.Net.Http.dll" />

    <!-- System.Web is not in the DNN folder but in the .net Framework installed on the server -->
    <Reference Include="System.Web" />
  </ItemGroup>

  <!-- Polymorphism
    If you're working with Polymorphism then you have many of the same files, which confuses Intellisense eg.
    - /live and /staging have the same files
    - /bs3 /bs4 / bs5 have the same files
    The following is meant to exclude some of these folders from intellisense
  -->
  <!-- Exclude /bs3 as we're always working on /bs5 -->
  <ItemGroup>
    <None Remove="bs3\**" />
    <Content Remove="bs3\**" />
    <Compile Remove="bs3\**" />
    <EmbeddedResource Remove="bs3\**" />
  </ItemGroup>
  <!-- Exclude /bs4 as we're always working on /bs5 -->
  <ItemGroup>
    <None Remove="bs4\**" />
    <Content Remove="bs4\**" />
    <Compile Remove="bs4\**" />
    <EmbeddedResource Remove="bs4\**" />
  </ItemGroup>
</Project>