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I have a VSIX extension which I have migrated to a new solution (basically to remove older projects targeting older VS versions no longer supported by my company) and to simplify the codebase for ease of maintenance.
Within the IDE, it does not matter if I set the active configuration to Debug|x86 or Release|x86, it will build a VSIX artifact OK. All good so far.
If I use
MSBuuild /t:Build /p:Configuration=Release /p:Platform=x86 -restore -detailedSummary MyExtension.sln
it will build without any errors, but no VSIX is produced.
I have poured over the terminal output and there are no warnings/errors and the DLL output of projects in the solution are produced.
I did read the following:
Project not selected to build for this solution configuration
The option to click deploy from the above link is not available for my VSIX - all the deploy options are disabled.
I have searched S.O. for similar issues regarding a VSIX not being produced, but none seem apt.
How should I debug this? What is different about a command-line MSBuild from the in-IDE build? Hopefully somebody has had a similar experience and can let me know what was causal for them, so that I can give something a try.
Update 1:
It transpired that although I was targeting .NET Framework 4.6, some .csproj references copied over from the migrated project had entries for net472, despite NuGet packages themselves being selected for compatibility with .NET Framework 4.6.
I had to manually edit a few .csproj files. There were some reference issues in associated projects that then needed fixing.
The residual issue now is as follows:
The in-IDE build fails with a single error...
A PackageReference to Microsoft.Build.* without ExcludeAssets="runtime" exists in your project. This will cause MSBuild assemblies to be copied to your output directory, causing your application to load them at runtime. To use the copy of MSBuild registered by MSBuildLocator, set ExcludeAssets="runtime" on the MSBuild PackageReferences. To disable this check, set the property DisableMSBuildAssemblyCopyCheck=true in your project file (not recommended as you must distributed all of MSBuild + associated toolset). Package(s) referenced: Microsoft.Build.Framework
So I grepped my source code folder for <PackageReference Include="Microsoft.Build and only a single project was in the result list. When I checked this project file, the entry in question did have ExcludeAssets="runtime" so I am unsure why the error is reported. I have tried project cleans followed by rebuild, or deleting bin and obj folders before building, to no avail.
I guess my question now is whether <Package Include="Microsoft.Build are relevant, since these are not <ReferencePackage Include elements as mentioned in the error message.
Update 2:
I hang my head in shame. PBKAC regarding Update 1 error. I had sent a copy of the code to a build engineer who committed it to a branch in our VCS. I then cloned this branch to a different location, and copy+pasted my more recent changes over the top. However, the grep tool (AstroGrep) I was using was still pointing at the older location not in the VCS. The older location contained package references with ExcludeAssets="runtime" as required. However, the newer location did not. Once I noticed this, I corrected it by editing the faulty .csproj file and the error from Update 1 went away.
However, I still appear to have the original issue the question is about.
I am awaiting my company's security team to approve the use of MSBuildLog so that I can get more detail and hopefully find the cause.
One other commenter suggest moving to solution PackageReference build rather than using packages.config. There is a question as to why this is needed. I am aware this seems like it could create a significant amount of extra work due to: this for which there are workarounds, but the commenter mentioned a "need" to use NuGet this way, when I think it is optional. I wish to understand more before committing to such a change.
Unfortunately, this is one of those things where it's a case of user beware.
When using NuGet, it is possible for it to appear to have succeeded in updating a NuGet reference, but unless one checks the underlying packages.config meticulously, you may not be getting what you think.
As I am migrating a solution that used packages.config instead of <Project Reference .../> elements in .csproj files, I have been caught out by IDE default behaviour changes.
NuGet seems to update the .csproj using <PacakageReference.../> elements by default. But this does not amend the packages.config entries that may already exist. As such, I ended up with a mish-mash that MSBuild seemed confused about at build time. Rather than throw an error, it just did not build what was expected.
The old packages.config files had entries targeting .NET Framework of net472 in some cases. I was adding NuGet references to earlier versions for net46 since this is what I need to target now, and this resulted in the problem behaviour, since any unchanged net472 entries were no good for producing the build output.
Since the project needs to support VS2015 also, I need to rely on packages.config approach and not <PackageReference.../> approach, which was not updating older references in the expected way.
As such, I had to remove the NuGet <PacakgeReference.../> and re-introduce correct package versions in packages.config. Once these were all correct, the VSIX built OK.
I'm getting a:
type or namespace name could not be found
error for a C# WPF app in VS2010. This area of code was compiling fine, but suddenly I'm getting this error. I've tried removing the Project Reference and the using statement, shutting VS2010 and restarting, but still I have this issue.
Any ideas why this might be occurring, where it seems like I'm doing the right thing re Reference & using statement?
I also noted in VS2010 that intellisense for that namespace is working ok, so it seems like VS2010 has the project reference and is seeing the namespace on one hand, but during compile doesn't see it?
This can be the result of a .Net framework version incompatibility between two projects.
It can happen in two ways:
a client profile project referencing a full framework project; or
an older framework version targeting a newer framework version
For example it will happen when an application is set to target the .Net 4 Client Profile framework, and the project it references targets the full .Net 4 framework.
So to make that clearer:
Project A targets the Client Profile framework
Project A references Project B
Project B targets the full framework
The solution in this case is to either upgrade the framework target of the application (Project A), or downgrade the target of referenced assembly (Project B). It is okay for a full framework app to reference/consume a client profile framework assembly, but not the other way round (client profile cannot reference full framework targeted assembly).
Note that you can also get this error when you create a new project in VS2012 or VS2013 (which uses .Net 4.5 as the default framework) and:
the referencing project(s) use .Net 4.0 (this is common when you have migrated from VS2010 to VS2012 or VS2013 and you then add a new project)
the referenced projects use a greater version i.e. 4.5.1 or 4.5.3 (you've re-targeted your existing projects to the latest version, but VS still creates new projects targeting v4.5, and you then reference those older projects from the new project)
Reinstalling nuget packages did the trick for me. After I changed .NET Framework versions to be in sync for all projects, some of the nuget packages (especially Entity Framework) were still installed for previous versions. This command in Packages Manager Console reinstalls packages for the whole solution:
Update-Package –reinstall
I've no idea why this worked, but I removed the project reference that VS2015 was telling me it couldn't find, and added it again. Solved the problem. I'd tried both cleaning, building and restarting VS to no avail.
When building the solution I was getting the same error (type or namespace ' ' could not be found). Below it I saw a warning stating that "the reference could not be resolved" and to make sure "the assembly exists on disk".
I was very confused, because my DLL was very clearly in the location that the reference was pointing to. VS didn't seem to highlight any errors, until I tried to build the solution.
I finally realized the problem (or at least what I suspect was the problem). I was building the library file in the same solution. So even though it existed on the disk, it was being rebuilt in that location (somehow in the process of the library getting rebuilt my other project - in the same solution - that referenced the library must have decided that the library didn't exist)
When I right-clicked on the project and built that only, instead of the entire solution, I didn't get the error.
To fix this problem I added the library as a dependency to the project that was using it.
To do this:
I right-clicked on my Solution in the Solution Explorer and selected
"Properties"
Then in "Common Properties" I selected "Project Dependencies".
Then in the Projects drop-down menu I selected the project that
relied on the library, and
Checked the box next to the library found under "Depends On"
This ensures that the library project gets built first.
First I would verify that your project's generated information isn't corrupt. Do a clean and rebuild on your solution.
If that doesn't help, one thing I've seen work in the past for designer issues is opening up a windows forms project, then closing it again. This is a little chicken-entrails-ish, though, so don't hold your breath.
A trickier situation I ran into was:
Project one targets the 4.0 full framework with Microsoft.Bcl.Async package installed.
Project two target the 4.0 full framework but would not compile when reference a Project one class.
Once I installed the Async NuGet package on the second project it compiled fine.
In my case, I find the reference in the VisualStudio have a triangle, and a exclamation mark as this image,
then, I right click remove it, and add the dll reference correctly again, the problem was solved.
I had a similar issue: The compiler was unable to detect a folder inside the same project, so a using directive linking to that folder generated an error. In my case, the problem originated from renaming the folder. Even though I updated the namespace of all the classes inside that folder, the project info somehow failed to update. I tried everything: deleting the .suo file and the bin and obj folders, cleaning the solution, reloading the project - nothing helped. I resolved the problem by deleting the folder and the classes inside, creating a new folder and creating new classes in that new folder (simply moving the classes inside the new folder didn't help).
PS: In my case I was working on a web application, but this problem may occur in different types of projects.
This one worked for me. In your class, where the class name is defined, eg: Public class ABC, remove one character and wait a little. You error list will increase because you have changed the name. Now put back the character that you have typed. This worked for me, hopefully it will work for you too. Good Luck!!!
[Facepalm] My issue was that I had added the dependency in the C++ way of doing things.
Go to the project that won't build, open up the 'References' folder in Solution Explorer, and see if your dependency is listed.
If not, you can 'Add Reference' and choose the dependency on the Projects tab.
Boom Shankar.
Check the Build Action of the .cs file containing the missing type. Make sure it's C# compiler.
Click on the .cs file containing the missing type.
Press F4 to bring up Properties.
Make sure Build Action is set to C# compiler.
Before:
After:
It even happens in Visual Studio 2017.
Restart Visual Studio
Clean project that fails to build.
Rebuild the project.
Had the same errors, my story was following:
after bad merging (via git) one of my .csproj files had duplicated compile entries like:
<Compile Include="Clients\Tree.cs" />
<Compile Include="Clients\Car.cs" />
<Compile Include="Clients\Tree.cs" /> //it's a duplicate
If you have a big solution and more than 300 messages in the errors window it's hard to detect this issue.
So I've opened damaged .csproj file via notepad and removed duplicated entries. Worked in my case.
I had same problem as discussed: VS 2017 underlines a class in referenced project as error but the solution builds ok and even intellisense works.
Here is how I managed to solve this issu:
Unload the referenced project
Open .proj file in VS ( i was looking for duplicates as someone suggested here)
Reload project again (I did not change or even save the proj file as I did not have any duplicates)
We had a weird case of this that I just fixed in a solution. There was a hidden/whitespace character in front of a "using" statement in the main project. That project would build fine and the website worked fine, but the unit test project that referenced it could not be built.
I encountered this problem when upgrading existing projects from VS2008 to VS2012. I found that two projects (the only two that I created) were targeting different .Net Frameworks (3.5 and 4.0). I resolved this on the Application tab of the projects by making sure that both projects had ".NET Framework 4" in the Target Framework box.
In my case I had a Class that was listed in the proper source folder, but was not registering in Solution Explorer. I had to do right click the project > Add Existing item and manually select that Class it said it was missing. Then everything worked fine!
I know its old, but I've found the same issue. My project did build, I then updated Visual Studio to the latest & the project wouldnt build as it couldnt find a type definition from a separate assembly. The other assembly built OK, the main project referenced it correctly & nothing had changed since it built OK.
I cleaned the whole solution & rebuilt it, it failed. I built the assembly on its own, it built OK. The project didnt build. I cleaned & built multiple times, and it failed. I then called a colleague to look at it, when I built with him watching, it all built OK.
I think Visual Studio tooling is the problem, especially as I just updated it.
In my case, I unload the project, then:
Opened myProject.csproj and update the ToolsVersion="4.0" to ToolsVersion="12.0"(I'm using vs 2017)(using Paulus's answer https://stackoverflow.com/a/64552201/1594487).
Deleted following lines from the myProject.csproj:
<Import Project="..\packages\EntityFramework.6.4.0\build\EntityFramework.props" Condition="Exists('..\packages\EntityFramework.6.4.0\build\EntityFramework.props')" />
<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
And the problem solved.
You might also try eliminating the code you think you're having problems with and seeing if it compiles with no references to that code. If not, fix things until it compiles again, and then work your suspected problem code back in. Sometimes I get strange errors about classes or methods that I know are correct when the compiler doesn't like something else. Once I fix the thing that it's really getting hung up on, these 'phantom' errors disappear.
I know this is kicking a dead horse but I had this error and the frameworks where fine. My problem was basically stating that an interface could not be found, yet it build and accessed just fine. So I got to thinking: "Why just this interface when others are working fine?"
It ended up that I was actually accessing a service using WCF with an endpoint's interface that was using Entity Version 6 and the rest of the projects were using version 5. Instead of using NuGet I simply copied the nuget packages to a local repository for reuse and listed them differently.
e.g. EntityFramework6.dll versus EntityFramework.dll.
I then added the references to the client project and poof, my error went away. I realize this is an edge case as most people will not mix versions of Entity Framework.
Adding my solution to the mix because it was a bit different and took me a while to figure out.
In my case I added a new class to one project but because my version control bindings weren't set I needed to make the file writable outside of Visual Studio (via the VC). I had cancelled out of the save in Visual Studio but after I made the file writable outside VS I then hit Save All again in VS. This inadvertently caused the new class file to not be saved in the project..however..Intellisense still showed it up as blue and valid in the referencing projects even though when I'd try to recompile the file wasn't found and got the type not found error. Closing and opening Visual Studio still showed the issue (but if I had taken note the class file was missing upon reopening).
Once I realized this, the fix was simple: with the project file set to writeable, readd the missing file to the project. All builds fine now.
I had the same issue. One night my project would compile the next morning ERRORS!.
I eventually found out that visual studio decided to "tweak" some of my references and point them elsewhere. for example:
System.ComponentModel.ISupportInitialize somehow became "blahblah.System.ComponentModel.ISupportInitialize"
Quite a rude thing for vs to do if you as me
My case was same as discussed here but nothing solved it until I've removed the System.Core reference from the references list (Everything worked fine without it)
hope it will help someone because this issue is quite frustrating
To solve this issue it can also help to delete and recreate the *.sln.DotSettings file of the associated solution.
Ok, years later using VS 2017 .NET Core 2.2 Razor Pages I feel this answer might help someone.
If it was a snake it would have bit me.
I was throwing stuff around, changing names, renaming Models, and all of a sudden I got this error:
Error CS0246 The type or namespace name 'UploadFileModel' could not be
found (are you missing a using directive or an assembly reference?)
This was underlined in red in my .chstml Razor Page. (not underlined after fix):
#page
#model UploadFileModel
So, finally, and luckily, I found the code from someone else that I had originally used, and low and behold, the namespace did not include the .cshtml file name!!!
Here is my bad dummy error spank myself with the page name in the namespace:
namespace OESAC.Pages.UploadFile
{
public class UploadFileModel : PageModel
{
What my original code had and all I had to do was delete the page name from the namespace, UploadFile:
namespace OESAC.Pages
{
public class UploadFileModel : PageModel
{
And low and behold, all the errors disappeared!!
Silly me. But you know, MS has made this .NET C# MVC stuff really confusing for us non-computer scientists. I am constantly tripping on my shoelaces trying to figure out model names, page names, and syntax to use them. It shouldn't be this hard. Oh well. I hope error and solution helps someone. The error was right, there is no Namespace named "UploadFileModel" haha.
In my case the problem was that after changing namespace to exactly same as is in another project (intentionally), the name of assembly was changed as well by VS, so there were two assemblies with same name, one overriding the other
Had the same problem after merging some new code into a vs2019 project.
Restarted VS, unloaded and reloaded projects, ensured all projects in solution had same ToolsVersion= and TargetFrameworkVersion. None of this helped.
I had a case of project Substrate, failing to find namespace Skin (in project Skin).
Finally I opened up Substrate.csproj and checked all the ProjectReference Include entries. The others were there, but no reference to Skin, even though Skin did show up in the check box of the little project dependencies dialog. So the project dependencies dialog took the check box for Skin (and saved it somewhere) but did not alter Substrate.csproj. I then added the ProjectReference Include manually, ensuring I had the correct path and GUID for the skin project.
<ProjectReference Include="..\Skin\Skin.csproj">
<Project>{1ad4b5d7-5014-4f5f-983e-2c59ac0e0028}</Project>
<Name>Skin</Name>
</ProjectReference>
I then saved the Substrate.csproj and the problem was solved. So as others have said this is a problem with VS tooling
In my case I had a file built by external dependency (xsd2code) and somehow its designer.cs files were not processed by VS correctly. Creating a new file in Visual Studio and pasting the code in it did the trick for me.
To anyone that is getting this error when they try to publish their website to Azure, none of the promising-looking solutions above helped me. I was in the same boat - my solution built fine on its own. I ended up having to
Remove all nuget packages in my solution.
Close and reopen my solution.
Re-add all the nuget packages.
A little painful but was the only way I could get my website to publish to Azure.
I get this as a warning when I build the solution. The weird part is that I removed those references long ago when I realized I didn't need them.
"Found conflicts between different versions of "System.Somenamespace.AnotherNamespace" that could not be resolved
I tried a Clean Solution then rebuild but no difference. I checked the solution and project files as well to see if there was a leftover reference but nothing. How do I clean this up?
Note: this is VS2017
Make sure nuget packages you use do not have discrepancies in their version. if so, you will either need to do assembly rebinding or use the exact same version across the solution. You can use the later by means of the “Consolidate” of the nuget package manager at the solution level.
I'm trying to figure out what the best way to handle this scenario is.
Let's say I have a library that's referenced by multiple different non-related solutions, let's call it WebServiceInterface.dll. This library has a dependency on JSON.NET.
Before NuGet
The JSON.NET binary was referenced via a SVN external in the WebServiceInterface project. Other solutions which had a dependency on WebServiceInterface referenced the project (also as an SVN external) and as a result pulled both the project, and it's dependencies.
With NuGet
I haven't figured out how to force the JSON.NET reference to be stored under the WebServiceInterface project (as opposed to the RandomSolution\packages location). I found reference # nu-get to project-level and solution-level pacakges, but I can't seem to find out how to specify this when I add a dependency via nu-get.
The goal here is that when someone checks out WebServiceInterface and adds it to a new solution that it builds (instead of having broken references to JSON.NET which point to the packages directory under whatever the last solution was that checked in).
When I went to find out if Chris B had created a NuGet issue for this, I couldn't find one. EDIT: He did, see his comment below. But I did find a semi-documented feature of NuGet that I used to solve this problem: Allow specifying the folder where packages are installed
Let me break this question into 2 issues:
getting NuGet to allow for multiple solutions to use the same packages location
getting the NuGet packages to automagically fetch from source control when you include a project that has NuGet packages
Problem 1:
By default NuGet stores packages in a packages folder in the solution's folder. To change that location, create a nuget.config file in the solution's root folder with the following contents:
<settings>
<repositoryPath>..\..\..\Utilities\Library\nuget.packages</repositoryPath>
</settings>
<repositoryPath> is relative to your solution; so obviously make it whatever you want. Make each solution have it's own relative path to the same packages folder.
As far as NuGet's flow, from that point, the paths in repositories.config are relative to the folder containing repositories.config, not the solution, so now all projects/packages are managed independent of the solution location.
This allows multiple solutions to use the same packages in source control, and if those solutions use the same projects (that use NuGet packages), those solutions/projects will all be kept in sync no matter which solution updates the package.
Problem 1 completely solved.
Problem 2:
Let me address this from 2 perspectives. This applies to Visual Studio and TFS -- I'll leave SVN for someone else to address.
First: if you have no source code on your drive and do a get of a solution (not a project), I prefer to make it so that you get everything that solution needs to build. There shouldn't be any missing references to go manually grab. That much we can do by adding the package files as solution items. Yes, in each solution. A bit of work, yes, but when it's done the package files will fetch/update from source control automagically.
Second: In a new solution, when you include an existing source control project that has NuGet packages, you have to manually fetch the packages from source control and add them as solution items. At least anyone else getting your solution in the future will automagically get everything they need to successfully build. At least with VS/TFS, this is just the way it is, AFAIK. If projB depends on projA, and you add projB to a new solution, VS/TFS won't automatically grab projA from TFS. You have to do that manually. So then the same goes for dll references (like NuGet packages).
Summary of my solution:
Only one copy of packages in source control for all solutions
Any solution can update packages and all the other solutions will be kept in sync*
* Once one solution updates packages to new paths or file names, they will appear as missing references to the other solutions and you'll have to manually clean that up. But at least you know right where the packages are in source control "(as opposed to the RandomSolution\packages location)."
The packages are always stored at the solution level, so if you install a package into multiple projects, they came from the same place. I don't believe you can configure it so that each project has its own packages folder.
I'm not sure there's a nice way to do what you're trying. You could maybe have a build step on the project that fetches the package, but I don't know how well that will suit you.
I'd recommend posting in the NuGet Issue Tracker to get a discussion going. The people working on it seem pretty active, so it might be something they can add support for in a future version :-)
I'm getting a:
type or namespace name could not be found
error for a C# WPF app in VS2010. This area of code was compiling fine, but suddenly I'm getting this error. I've tried removing the Project Reference and the using statement, shutting VS2010 and restarting, but still I have this issue.
Any ideas why this might be occurring, where it seems like I'm doing the right thing re Reference & using statement?
I also noted in VS2010 that intellisense for that namespace is working ok, so it seems like VS2010 has the project reference and is seeing the namespace on one hand, but during compile doesn't see it?
This can be the result of a .Net framework version incompatibility between two projects.
It can happen in two ways:
a client profile project referencing a full framework project; or
an older framework version targeting a newer framework version
For example it will happen when an application is set to target the .Net 4 Client Profile framework, and the project it references targets the full .Net 4 framework.
So to make that clearer:
Project A targets the Client Profile framework
Project A references Project B
Project B targets the full framework
The solution in this case is to either upgrade the framework target of the application (Project A), or downgrade the target of referenced assembly (Project B). It is okay for a full framework app to reference/consume a client profile framework assembly, but not the other way round (client profile cannot reference full framework targeted assembly).
Note that you can also get this error when you create a new project in VS2012 or VS2013 (which uses .Net 4.5 as the default framework) and:
the referencing project(s) use .Net 4.0 (this is common when you have migrated from VS2010 to VS2012 or VS2013 and you then add a new project)
the referenced projects use a greater version i.e. 4.5.1 or 4.5.3 (you've re-targeted your existing projects to the latest version, but VS still creates new projects targeting v4.5, and you then reference those older projects from the new project)
Reinstalling nuget packages did the trick for me. After I changed .NET Framework versions to be in sync for all projects, some of the nuget packages (especially Entity Framework) were still installed for previous versions. This command in Packages Manager Console reinstalls packages for the whole solution:
Update-Package –reinstall
I've no idea why this worked, but I removed the project reference that VS2015 was telling me it couldn't find, and added it again. Solved the problem. I'd tried both cleaning, building and restarting VS to no avail.
When building the solution I was getting the same error (type or namespace ' ' could not be found). Below it I saw a warning stating that "the reference could not be resolved" and to make sure "the assembly exists on disk".
I was very confused, because my DLL was very clearly in the location that the reference was pointing to. VS didn't seem to highlight any errors, until I tried to build the solution.
I finally realized the problem (or at least what I suspect was the problem). I was building the library file in the same solution. So even though it existed on the disk, it was being rebuilt in that location (somehow in the process of the library getting rebuilt my other project - in the same solution - that referenced the library must have decided that the library didn't exist)
When I right-clicked on the project and built that only, instead of the entire solution, I didn't get the error.
To fix this problem I added the library as a dependency to the project that was using it.
To do this:
I right-clicked on my Solution in the Solution Explorer and selected
"Properties"
Then in "Common Properties" I selected "Project Dependencies".
Then in the Projects drop-down menu I selected the project that
relied on the library, and
Checked the box next to the library found under "Depends On"
This ensures that the library project gets built first.
First I would verify that your project's generated information isn't corrupt. Do a clean and rebuild on your solution.
If that doesn't help, one thing I've seen work in the past for designer issues is opening up a windows forms project, then closing it again. This is a little chicken-entrails-ish, though, so don't hold your breath.
A trickier situation I ran into was:
Project one targets the 4.0 full framework with Microsoft.Bcl.Async package installed.
Project two target the 4.0 full framework but would not compile when reference a Project one class.
Once I installed the Async NuGet package on the second project it compiled fine.
In my case, I find the reference in the VisualStudio have a triangle, and a exclamation mark as this image,
then, I right click remove it, and add the dll reference correctly again, the problem was solved.
I had a similar issue: The compiler was unable to detect a folder inside the same project, so a using directive linking to that folder generated an error. In my case, the problem originated from renaming the folder. Even though I updated the namespace of all the classes inside that folder, the project info somehow failed to update. I tried everything: deleting the .suo file and the bin and obj folders, cleaning the solution, reloading the project - nothing helped. I resolved the problem by deleting the folder and the classes inside, creating a new folder and creating new classes in that new folder (simply moving the classes inside the new folder didn't help).
PS: In my case I was working on a web application, but this problem may occur in different types of projects.
This one worked for me. In your class, where the class name is defined, eg: Public class ABC, remove one character and wait a little. You error list will increase because you have changed the name. Now put back the character that you have typed. This worked for me, hopefully it will work for you too. Good Luck!!!
[Facepalm] My issue was that I had added the dependency in the C++ way of doing things.
Go to the project that won't build, open up the 'References' folder in Solution Explorer, and see if your dependency is listed.
If not, you can 'Add Reference' and choose the dependency on the Projects tab.
Boom Shankar.
Check the Build Action of the .cs file containing the missing type. Make sure it's C# compiler.
Click on the .cs file containing the missing type.
Press F4 to bring up Properties.
Make sure Build Action is set to C# compiler.
Before:
After:
It even happens in Visual Studio 2017.
Restart Visual Studio
Clean project that fails to build.
Rebuild the project.
Had the same errors, my story was following:
after bad merging (via git) one of my .csproj files had duplicated compile entries like:
<Compile Include="Clients\Tree.cs" />
<Compile Include="Clients\Car.cs" />
<Compile Include="Clients\Tree.cs" /> //it's a duplicate
If you have a big solution and more than 300 messages in the errors window it's hard to detect this issue.
So I've opened damaged .csproj file via notepad and removed duplicated entries. Worked in my case.
I had same problem as discussed: VS 2017 underlines a class in referenced project as error but the solution builds ok and even intellisense works.
Here is how I managed to solve this issu:
Unload the referenced project
Open .proj file in VS ( i was looking for duplicates as someone suggested here)
Reload project again (I did not change or even save the proj file as I did not have any duplicates)
We had a weird case of this that I just fixed in a solution. There was a hidden/whitespace character in front of a "using" statement in the main project. That project would build fine and the website worked fine, but the unit test project that referenced it could not be built.
I encountered this problem when upgrading existing projects from VS2008 to VS2012. I found that two projects (the only two that I created) were targeting different .Net Frameworks (3.5 and 4.0). I resolved this on the Application tab of the projects by making sure that both projects had ".NET Framework 4" in the Target Framework box.
In my case I had a Class that was listed in the proper source folder, but was not registering in Solution Explorer. I had to do right click the project > Add Existing item and manually select that Class it said it was missing. Then everything worked fine!
I know its old, but I've found the same issue. My project did build, I then updated Visual Studio to the latest & the project wouldnt build as it couldnt find a type definition from a separate assembly. The other assembly built OK, the main project referenced it correctly & nothing had changed since it built OK.
I cleaned the whole solution & rebuilt it, it failed. I built the assembly on its own, it built OK. The project didnt build. I cleaned & built multiple times, and it failed. I then called a colleague to look at it, when I built with him watching, it all built OK.
I think Visual Studio tooling is the problem, especially as I just updated it.
In my case, I unload the project, then:
Opened myProject.csproj and update the ToolsVersion="4.0" to ToolsVersion="12.0"(I'm using vs 2017)(using Paulus's answer https://stackoverflow.com/a/64552201/1594487).
Deleted following lines from the myProject.csproj:
<Import Project="..\packages\EntityFramework.6.4.0\build\EntityFramework.props" Condition="Exists('..\packages\EntityFramework.6.4.0\build\EntityFramework.props')" />
<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
And the problem solved.
You might also try eliminating the code you think you're having problems with and seeing if it compiles with no references to that code. If not, fix things until it compiles again, and then work your suspected problem code back in. Sometimes I get strange errors about classes or methods that I know are correct when the compiler doesn't like something else. Once I fix the thing that it's really getting hung up on, these 'phantom' errors disappear.
I know this is kicking a dead horse but I had this error and the frameworks where fine. My problem was basically stating that an interface could not be found, yet it build and accessed just fine. So I got to thinking: "Why just this interface when others are working fine?"
It ended up that I was actually accessing a service using WCF with an endpoint's interface that was using Entity Version 6 and the rest of the projects were using version 5. Instead of using NuGet I simply copied the nuget packages to a local repository for reuse and listed them differently.
e.g. EntityFramework6.dll versus EntityFramework.dll.
I then added the references to the client project and poof, my error went away. I realize this is an edge case as most people will not mix versions of Entity Framework.
Adding my solution to the mix because it was a bit different and took me a while to figure out.
In my case I added a new class to one project but because my version control bindings weren't set I needed to make the file writable outside of Visual Studio (via the VC). I had cancelled out of the save in Visual Studio but after I made the file writable outside VS I then hit Save All again in VS. This inadvertently caused the new class file to not be saved in the project..however..Intellisense still showed it up as blue and valid in the referencing projects even though when I'd try to recompile the file wasn't found and got the type not found error. Closing and opening Visual Studio still showed the issue (but if I had taken note the class file was missing upon reopening).
Once I realized this, the fix was simple: with the project file set to writeable, readd the missing file to the project. All builds fine now.
I had the same issue. One night my project would compile the next morning ERRORS!.
I eventually found out that visual studio decided to "tweak" some of my references and point them elsewhere. for example:
System.ComponentModel.ISupportInitialize somehow became "blahblah.System.ComponentModel.ISupportInitialize"
Quite a rude thing for vs to do if you as me
My case was same as discussed here but nothing solved it until I've removed the System.Core reference from the references list (Everything worked fine without it)
hope it will help someone because this issue is quite frustrating
To solve this issue it can also help to delete and recreate the *.sln.DotSettings file of the associated solution.
Ok, years later using VS 2017 .NET Core 2.2 Razor Pages I feel this answer might help someone.
If it was a snake it would have bit me.
I was throwing stuff around, changing names, renaming Models, and all of a sudden I got this error:
Error CS0246 The type or namespace name 'UploadFileModel' could not be
found (are you missing a using directive or an assembly reference?)
This was underlined in red in my .chstml Razor Page. (not underlined after fix):
#page
#model UploadFileModel
So, finally, and luckily, I found the code from someone else that I had originally used, and low and behold, the namespace did not include the .cshtml file name!!!
Here is my bad dummy error spank myself with the page name in the namespace:
namespace OESAC.Pages.UploadFile
{
public class UploadFileModel : PageModel
{
What my original code had and all I had to do was delete the page name from the namespace, UploadFile:
namespace OESAC.Pages
{
public class UploadFileModel : PageModel
{
And low and behold, all the errors disappeared!!
Silly me. But you know, MS has made this .NET C# MVC stuff really confusing for us non-computer scientists. I am constantly tripping on my shoelaces trying to figure out model names, page names, and syntax to use them. It shouldn't be this hard. Oh well. I hope error and solution helps someone. The error was right, there is no Namespace named "UploadFileModel" haha.
In my case the problem was that after changing namespace to exactly same as is in another project (intentionally), the name of assembly was changed as well by VS, so there were two assemblies with same name, one overriding the other
Had the same problem after merging some new code into a vs2019 project.
Restarted VS, unloaded and reloaded projects, ensured all projects in solution had same ToolsVersion= and TargetFrameworkVersion. None of this helped.
I had a case of project Substrate, failing to find namespace Skin (in project Skin).
Finally I opened up Substrate.csproj and checked all the ProjectReference Include entries. The others were there, but no reference to Skin, even though Skin did show up in the check box of the little project dependencies dialog. So the project dependencies dialog took the check box for Skin (and saved it somewhere) but did not alter Substrate.csproj. I then added the ProjectReference Include manually, ensuring I had the correct path and GUID for the skin project.
<ProjectReference Include="..\Skin\Skin.csproj">
<Project>{1ad4b5d7-5014-4f5f-983e-2c59ac0e0028}</Project>
<Name>Skin</Name>
</ProjectReference>
I then saved the Substrate.csproj and the problem was solved. So as others have said this is a problem with VS tooling
In my case I had a file built by external dependency (xsd2code) and somehow its designer.cs files were not processed by VS correctly. Creating a new file in Visual Studio and pasting the code in it did the trick for me.
To anyone that is getting this error when they try to publish their website to Azure, none of the promising-looking solutions above helped me. I was in the same boat - my solution built fine on its own. I ended up having to
Remove all nuget packages in my solution.
Close and reopen my solution.
Re-add all the nuget packages.
A little painful but was the only way I could get my website to publish to Azure.