NuGet package Microsoft.SqlServer.Compact does not copy native DLLs - visual-studio

Question

I have created a .NET Framework 4.8 C# Class Library project that uses x64 as the TargetFramework.
I have added the NuGet package Microsoft.SqlServer.Compact to the project.
When I build the project, only the System.Data.SqlServerCe.dll file, which sits flat in the \lib\net40 folder, is copied to the Output folder.
The files that are in the NativeBinaries\amd64\ directory of the NuGet package are not copied.
But I need them in the OutputPath\amd64 directory.
What settings do I need to make so that these files are also copied?
Edit
Here is the content of my csproj file:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProjectGuid>{409AD54E-75FD-419F-B5D7-D2368105B4A8}</ProjectGuid>
<OutputType>Library</OutputType>
<AppDesignerFolder>Properties</AppDesignerFolder>
<RootNamespace>NuGetSQLTestClassLibraryNetFramework</RootNamespace>
<AssemblyName>NuGetSQLTestClassLibraryNetFramework</AssemblyName>
<TargetFrameworkVersion>v4.8</TargetFrameworkVersion>
<FileAlignment>512</FileAlignment>
<Deterministic>true</Deterministic>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
<DebugSymbols>true</DebugSymbols>
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<OutputPath>bin\Debug\</OutputPath>
<DefineConstants>DEBUG;TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
<PlatformTarget>x64</PlatformTarget>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
<DebugType>pdbonly</DebugType>
<Optimize>true</Optimize>
<OutputPath>bin\Release\</OutputPath>
<DefineConstants>TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<ItemGroup>
<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.Net.Http" />
<Reference Include="System.Xml" />
</ItemGroup>
<ItemGroup>
<Compile Include="Class1.cs" />
<Compile Include="Properties\AssemblyInfo.cs" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="Microsoft.SqlServer.Compact">
<Version>4.0.8876.1</Version>
</PackageReference>
</ItemGroup>
<Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
</Project>

Answer 1

In my side, it works well and I have OutputPath\amd64 directory with the nuget package.
So please try the following steps to troubleshoot the issue:
1) clean nuget caches first or just delete all files under C:\Users\xxx\.nuget\packages
Also, delete the packages folder under <solution_folder>.
2) run update-package -reinstall under Tools-->Nuget Package Manager-->Package Manager Console
Update
Since you have used PackageReference nuget management format and you cannot get what you want in that format since the author did not consider the compatibility of PackageReference with the nuget package.
In my side, I used packages.config nuget management format and then get that.
To get what you want, you should add these additionally:
1) add this <GeneratePathProperty>true</GeneratePathProperty>under that nuget package reference node to generate msbuild property called PkgMicrosoft_SqlServer_Compact about the content path of the nupkg.
<ItemGroup>
<PackageReference Include="Microsoft.SqlServer.Compact">
<Version>4.0.8876.1</Version>
<GeneratePathProperty>true</GeneratePathProperty>
</PackageReference>
</ItemGroup>
2) right-click on the Proeject Properties-->Build Events-->post-build event command line--> add these:
if not exist "$(TargetDir)x86" md "$(TargetDir)x86"
xcopy /s /y "$(PkgMicrosoft_SqlServer_Compact)\NativeBinaries\x86\*.*" "$(TargetDir)x86"
if not exist "$(TargetDir)amd64" md "$(TargetDir)amd64"
xcopy /s /y "$(PkgMicrosoft_SqlServer_Compact)\NativeBinaries\amd64\*.*" "$(TargetDir)amd64"
After that, rebuild to get what you want.