Develop Reference

Project reference not resolved when running dotnet build

I have a Visual Studio 2022 solution, with multiple projects, but four in particular are interesting here.
Provider1 which is based on .NET Framework 4.
Provider2 which is based on .NET 6.
Provider1Test which is based on .NET Framework 4.
Provider2Test which is based on .NET 6.
The Provider1 project has a number of classes, all in the Provider.Data namespace, one of them being Class1. This is my source code. The Provider1.csproj file:
<ItemGroup>
<Compile Include="Class1.cs">
<SubType>Code</SubType>
</Compile>
...
</ItemGroup>
The Class1.cs file:
namespace Provider.Data
{
public class Class1
{
...
}
}
The Provider2 project has links to these source files, i.e. "Add"->"Existing item"->"As link". It compiles with different conditional compilation symbols, so the output is not the same as for the Provider1 project.
The Provider2.csproj file:
<ItemGroup>
<Compile Include="..\Provider1\Class1.cs" Link="Class1.cs" />
</ItemGroup>
The Provider1Test project is an NUnit test project, that tests Provider1. It has multiple test classes, one of them is TestClass1.
The Provider2Test project is also a NUnit test project, with a ProjectReference to Provider2. It links to the test classes in Provider1Test in the same way as the source code does. The Provider2Test.csproj file:
<ItemGroup>
<ProjectReference Include="..\Provider2\Provider2.csproj" />
</ItemGroup>
<ItemGroup>
<Compile Include="..\Provider1Test\TestClass1.cs" Link="TestClass1.cs" />
</ItemGroup>
The TestClass1.cs file:
using Provider.Data;
namespace ProviderTests
{
public class TestClass1
{
...
}
}
Now, this builds and runs just fine inside Visual Studio, but if I navigate to the Provider2Test folder and try to build with the dotnet build command, it doesn't find the source code.
C:\dev\DataProvider\Provider2Test>dotnet build
MSBuild version 17.3.1+2badb37d1 for .NET
Determining projects to restore...
All projects are up-to-date for restore.
Provider2 -> C:\dev\DataProvider\Provider2\bin\x64\Debug\net6.0\Provider.Data.dll
1 file(s) copied.
C:\dev\DataProvider\Provider1Test\TestClass1.cs(14,7): error CS0246: The type or namespace name 'Provider' could not be found (are you missing a using directive or an assembly reference?) [C:\dev\DataProvider\Provider2Test\Provider2Test.csproj]
Build FAILED.
What is the issue here, why doesn't dotnet build follow the reference path here, and how do I solve it?
I tried to create a TestClass2.cs file directly in Provider2Test, that is not a link but a standard compile include, and also using the Provider.Data namespace. It produces the same error.

I found a workaround, so I'm posting it here and I'm going with it for now, but I don't think it's a good solution, and it doesn't explain the original issue, so I'm not going to mark this as the accepted answer.
In Provider2.csproj, I added that if it is built with dotnet build, it has a post-build event that copies its source code dll to Provider2Test. This is not run if the project is build within Visual Studio ("$(MSBuildRuntimeType)" == "Full").
if "$(MSBuildRuntimeType)" == "Core" XCOPY "$(OutDir)Provider.Data.dll" "$(ProjectDir)..\Provider2Test\$(OutDir)" /Y /F
In Provider2Test.csproj I added a conditional assembly reference.
<ItemGroup>
<Reference Include="Provider.Data" Condition="$(MSBuildRuntimeType) == 'Core'">
<HintPath>$(OutDir)Provider.Data.dll</HintPath>
</Reference>
</ItemGroup>
I kept the ProjectReference in all cases (both "Full" and "Core"), in order to trigger a Provider2 build whenever Provider2Test is built.

Published .Net Core C# console app not finding COM dependency ("An assembly specified in the app dependencies manifest was not found")?

I'm attempting to publish a .net core c# console app (tested in both debug and release). However when I run the published exe, I receive the error message "An assembly specified in the app dependencies manifest was not found". It can't locate the .dll for my COM dependency "Interop.Microsoft.Office.Interop.Excel". My .csproj file has the following itemgroup for it:
<ItemGroup>
<COMReference Include="Microsoft.Office.Excel.dll">
<Guid>00020813-0000-0000-c000-000000000046</Guid>
<VersionMajor>1</VersionMajor>
<VersionMinor>9</VersionMinor>
<WrapperTool>tlbimp</WrapperTool>
<Lcid>0</Lcid>
<Isolated>false</Isolated>
</COMReference>
</ItemGroup>
I've found similar questions with various answers, usually tweaking the publish settings, but nothing's worked for me so far. I'm using win-64 runtime and I've tried both deployment modes (framework dependent and self-contained). All of my dependencies are up-to-date.

NuGet Msbuild Pack with non-SDK project

I have an "old style" .NET framework project which includes nuget references and other project references. Now I switched to the PackageReference format (removed the packages.config). I want to create a NuGet package for my project. So I added a reference to the "NuGet.Build.Tasks.Pack" package and used the MSBUILD pack target. In the first place it looked everything as expected, the resulting package contains all my references and the corresponding NuGet references. Now I have the problem, that I use also a project to project reference:
<ProjectReference Include="..\Wrapper\MyWrapper\MyWrapper.csproj">
<Project>{6b9a7dd0-b93f-3a5e-8fdf-99d0bf811652}</Project>
<Name>MyWrapper</Name>
</ProjectReference>
Based on the nuget documentation - for this reference:
Project to project references are considered by default as nuget
package references
But I want that this project reference is packaged into my package instead of a "nuget package reference". I found postings that using
PrivateAssets="all"
for the project reference could fix the problem, but adding this attribute to the project reference node does not change anything. Any help would be great!

I think you have missed something. It is not enough that you set PrivateAssets="all" for the ProjectReference. And actually, nuget will not view the referenced project as a nuget dependency and also nuget will not pack its assembly dll into the nupkg. You need other nodes.
Try these guidances:
Assume all your lib projects are target to net framework 4.7.2.
1) add the PrivateAssets="all" on the xxx.csproj file of the main project.
<ProjectReference Include="..\Wrapper\MyWrapper\MyWrapper.csproj">
<Project>{6b9a7dd0-b93f-3a5e-8fdf-99d0bf811652}</Project>
<Name>MyWrapper</Name>
<PrivateAssets>All</PrivateAssets>
</ProjectReference>
2) also add these node on the xxx.csproj file of the main project to pack the assembly dll into the nupkg:
<PropertyGroup>
<TargetsForTfmSpecificBuildOutput>$(TargetsForTfmSpecificBuildOutput);CopyProjectReferencesToPackage</TargetsForTfmSpecificBuildOutput>
</PropertyGroup>
<Target Name="CopyProjectReferencesToPackage" DependsOnTargets="ResolveReferences">
<ItemGroup>
<BuildOutputInPackage Include="#(ReferenceCopyLocalPaths->WithMetadataValue('ReferenceSourceTarget', 'ProjectReference'))" />
</ItemGroup>
</Target>
3) then use this command to pack the project:
msbuild -t:rebuild,pack -p:PackageOutputPath=xxx\xxx -p:Authors="xxx" -p:Version="x.x.x"
Note: In my side, the main project called Mod and it references a project called Mod1. When I finish the pack process, you can see these in the nupkg.
It packs the refeneced dll as a lib rather than a nuget package.

The type 'MySqlConnection' exists in both 'MySql.Data Issue

I have Referenced MySql.Data on one project and Other project referenced nuget package which also referenced MySqlConnector inside of it. projects has dependency .
when i compile application im getting this error
This is application hierarchy
is there any way to avoid this? or did i do anything wrong when referencing packages?
Thanks
UPDATE
this is the same namespaces from difference libs
UPDATE 2
This is the sample repo which reproduced same issue

In NET.Framework projects you can go to the reference properties and set an alias for assembly. Net core projects doesn't fully support yet aliases for assemblies. But there is a workaround to use aliases in .net core. Edit your csproj file like this:
<Project Sdk="Microsoft.NET.Sdk.Web">
...
<Target Name="ChangeAliasesOfStrongNameAssemblies" BeforeTargets="FindReferenceAssembliesForReferences;ResolveReferences">
<ItemGroup>
<ReferencePath Condition="'%(FileName)' == 'MySqlConnector'">
<Aliases>MySqlConnectorAlias</Aliases>
</ReferencePath>
</ItemGroup>
</Target>
...
</Project>
then in your cs file before all usings:
extern alias MySqlConnectorAlias;
then you can reference to you type from MySqlConnector like this:
MySqlConnectorAlias::MySql.Data.MySqlClient.MySqlConnection

It will work If you remove mysql.data reference from Your project/references.
Hope it will work for you. for me it was worked. My project is ASP.NET Core Framework. Created project in VS2017 and opening in VS2019 at that time it introduced.

Add project.json package references to a VSIX

When trying to add references to a VSIX, it normally pulls it from the references in the .csproj. However, if the references are not in the .csproj, because they now are in a project.json file, then they don't get pulled to the vsix. The solution then may compile, but then the extension fails with "file not found" errors when installed into Visual Studio (since the assemblies where not copied to the VSIX).
I tried with the section of the manifest like so:
<Asset Type="Microsoft.VisualStudio.Assembly" d:Source="Project" d:ProjectName="*PROJECTNAME*" Path="|*ASSEMBLYNAME*|" AssemblyName="|*ASSEMBLYNAME*;AssemblyName|" />
But it does not work, as it does not recognize the package references.
After some research I saw a similar issue with a PCL, however, without an answer and not the same type of problem: MEF With Portable Class library using Microsoft Composition MEF2 throws file not found exception
In the same note, this seems like an acceptable workaround: VSIX with Project Templates and NuGet Packages however, as far as I understood, it implies using the package during the installation. Besides that, it doesn't work for our case as they need to specify the package version and we are using project.json so we can use floating versions (ie: 2.0.*)
Is there a way to reference this project.json references that we are missing? Maybe a workaround? The solutions I have found seem to all require to "paste" de DLL somewhere, which for floating versions is not that convenient.
Thanks in advance for any help or input.
Edit/Update: Since VSIX automatically pushes any assembly referenced in the CSPROJ (and not the project itself), trying to get the DLLs at a project level seems unlikely. After many tries, I think that a valid workaround would be to get the assemblies from the Output Folder. However, to my knowledge, VSIX does not have a way of doing this, or does it?

I'm not sure I'm understanding your question correctly, but if you're trying to install a Project Template via a VSIX and you want the project template to include all it's nuget packages when you use it you could do something like this.
Edit your Project Template's xproj file and add the following lines:
<ItemGroup>
<None Include="project.json"/>
<None Include="project.lock.json"/>
</ItemGroup>
Edit your Project Template's vstemplate file and add the following lines in the Project node:
<ProjectItem ReplaceParameters="true" TargetFileName="project.json">project.json</ProjectItem>
<ProjectItem ReplaceParameters="true" TargetFileName="project.lock.json">project.lock.json</ProjectItem>
That should be all you need to do. Now when you install the project template, then create a new project using that template it should include all the nuget packages that were in the project.json file.