Important points when developing plugins


- All views (cshtml files) and web.config file should have "Build action" set to "Content" and "Copy to output directory" set to "Copy if newer"

- When you develop a new plugin from scratch, and when a new class library is added to the solution, open its .csproj file (a main project file) in any text editor and replace its content with the following one

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp2.2</TargetFramework> 
    <OutputPath>..\..\Presentation\Nop.Web\Plugins\PLUGIN_OUTPUT_DIRECTORY</OutputPath>
    <OutDir>$(OutputPath)</OutDir>
	<!--Set this parameter to true to get the dlls copied from the NuGet cache to the output of your project.
    You need to set this parameter to true if your plugin has a nuget package 
    to ensure that the dlls copied from the NuGet cache to the output of your project-->
    <CopyLocalLockFileAssemblies>false</CopyLocalLockFileAssemblies>
  </PropertyGroup>

  <ItemGroup>    
    <ClearPluginAssemblies Include="$(MSBuildProjectDirectory)\..\..\Build\ClearPluginAssemblies.proj" />
  </ItemGroup>

  <!-- This target execute after "Build" target -->
  <Target Name="NopTarget" AfterTargets="Build">
    <!-- Delete unnecessary libraries from plugins path -->
    <MSBuild Projects="@(ClearPluginAssemblies)" Properties="PluginPath=$(MSBuildProjectDirectory)\$(OutDir)" Targets="NopClear" />
  </Target>
</Project>

Replace “PLUGIN_OUTPUT_DIRECTORY” in the code above with your real plugin output directory name. 

It’s not required. But this way we can use a new ASP.NET approach to add third-party references. It was introduced in .NET Core. Furthermore, references from already referenced libraries will be loaded automatically. It’s very convenient.