I'm trying to get an existing MVC4 app running on a new machine but encountering the issue:
The installed version of MVC4 is:
It appears there is a problem with the compatibility of MVC and Structure map, but I cannot see the difference between the installations on the working and non-working machines.
Has anyone experienced this issue or have a suggestion of what might resolve it? Please ask if more info is required about versions and other installed software.
Thanks
I have resolved this issue by installing "StructureMap.MVC4" version 3.0.2.115 from NuGet.
After migrating A DotNetCore application from VS2015 to VS2017, I am getting a Reference error when I try to run the application.
If I try to manage my nuget packages I get an 'nuget configuration is invalid' error. In the output window i see lots of "
TF10121: The path '///[NuGetDependency;;;;]' is not found or not
supported. Type or select a different path.
"
I tried searching the internet but couldn't find any solution.
The last time I faced this issue, restarting VS 2017 helped. Make sure you have the latest updates installed for VS 2017.
I've installed the newly released version of Visual Studio 2017 and started a fresh ASP.NET Core project targeting .NET Core.
Out of the box, I'm getting the
The type or namespace name 'System' could not be found (are you
missing a using directive or an assembly reference?)
error. Any idea what's causing this and how to fix it?
Also, looks like there are problems with NuGet packages as well:
I also tried dotnet restore on the project through the command line and got the following error:
P.S. Kind of disheartening that you get an error in a fresh new project in the latest version of Visual Studio 2017!
UPDATE:
SDK version is v 1.0.1 -- see below:
UPDATE 2:
This is very strange. Looks like the original problem was due to NuGet package source pointing to a folder under Visual Studio 2015 folder. I unchecked it and left only nuget.org. With that my project seemed to have restored all the packages and when I started the project it loads up the standard ASP.NET page. But if I open startup.cs file, I get red squigglies all over the place but if I run the project, it works fine. What's going on here?
UPDATE 3:
I closed the project and VS 2017. I then restarted VS 2017 and opened the project and now it seems to be fine. And I'm not referencing the .NETStandard library 1.6.1 and everything seems to be working fine now.
I had the same issue in my Visual studio 2017 .Net Core application. I closed the Visual studio and re-open fixed everything.
Came across the same issue today. I had an old nuget source that no longer existed. So I went into Tools > Nuget Packet Manager and un-checked the wrong one. Hit "Ok", and then rebuilt the project, and it works great now. It seems like you stumbled onto it, but also wanted to verify that it fixed my issue, and it does.
I had the same problem, first when converting a VS2015 net core mvc web project to 2017 and then when trying to create a new core web application in 2017.
Went to Tools|NuGet Package Manager|Package Manager Settings - checked 'Allow NuGet to download missing packages' and 'Automatically check for missing packages during build in VS' and then clicked 'Clear All NuGet Cache(s)'.
Then re-built the solution - it found and loaded all the required packages and ran OK.
May not work for all cases but simple and worth a try.
Multiple closing and reopening of VS2017 fixed it for me.
I had the same issue, the solution for me was to clear the NuGet cache. Tools > NuGet Package Manager > Package Manager Settings > Clear All NuGet Cache(s)
Check the version .NET Command Line Tools in CMD, just type dotnet --info. If version is 1.0.0, then try to install latest version .NET Core SDK from here.
Find the broken project and right click, Unload, right click, Re-load. Fastest fix for me.
If you get the problem while using the CLI, try doing nuget restore instead of dotnet restore as that sometimes pulls down packages that the dotnet CLI seems to miss.
I have had the same issue with Visual Studio 2019 and .NET Core SDK 2.2.
These steps solved the problem:
Close the Visual Studio
Open the Visual Studio as Administrator
Open the Solution
Right click on Solution -> Restore NuGet Packages
I've tried all answers above. For me works only removal and adding the reference again described in the following steps:
Open 'References' under the project.
Right click on 'System' reference.
Click on 'Remove'.
Right click on 'References'.
Click 'Add Reference...'.
From right menu choose an 'Assemblies',
In a search field type 'System'.
Choose 'System' from the list.
Click 'Add' button.
IMPORTANT: Restart the Visual Studio.
'System' reference you can replace with any you need.
Try adding the following line above the other references in the csproj file
<Reference Include="netstandard" />
For me the problem was caused by my project having a custom IntermediateOutputPath. For some reason, if project_name.csproj.nuget.g.targets is not in obj subfolder of project folder, the error occurs.
Using default IntermediateOutputPath or keeping a shadow copy of project_name.csproj.nuget.g.targets in fake obj folder solves the problem for me.
This issue seems to be triggered by a myriad of reasons. Mine was caused by cloning directly from VSTS using Git Bash, my project directory had spaces in it. Git Bash changed those spaces in the path to %20. It was throwing off all the references in my project. So for anyone who tried everything else and are at their wits end, make sure %20 is not in the path.
So, I have cloned the repository from github and started getting this error.
It was my project uploaded from another machine. I later realized that I have used the materialdesign packages in my project.
I have uninstalled and reinstalled these packages and it fixed my issue.
Had the same problem. Uninstalled Application Insights from my projects using the nuget package manager. I'm not looking at that yet, I just wanted core and unit tests. Problem solved.
I also had the same problem.
The is no SDK folder under the Dependencies one. Therefore, no Microsoft.NetCore.App libraries !
To solve this problem, in Nuget manager window, install any nuget which depends on .NetCoreApp (you can install for example Microsoft.AspNetCore or BundlerMinifier.Core from the Microsoft Visual Studio Offline Packages source).
The SDK will be restored by the same time.
Once it is back, you can uninstall the previously added nuget. The SDK will remain in place.
Not quite sure in which order vs 2017 trying to resolve packages.
But my situation was following. In my VS2015 I had configured local and 3rd party source for nuget packages, newly installed version of 2017 loaded them too.
https://api.nuget.org/v3/index.json was first in list.
But vs2017 throwed an error that it can't restore .net core libraries from my another local repo.
After I unchecked all of them except https://api.nuget.org/v3/index.json, it had started to working normally.
I had this problem too, but not right now, this steps solved my problem: Choose Project -> Properties from the menu bar. In the Project properties window, under Configuration Properties -> General, make sure that Common Language Runtime Support is set to Common Language Runtime Support (/clr)
Simply opening the NuGet package manager and then the Visual Studio settings related to it - without changing anything - merely looking around, and when I closed out, the problem was gone.
This seems to be an intermittent issue that can come and go for no obvious reason.
None of the answers here worked for me so I'm posting what did work.
My errors were mostly the same as the original poster but I also had:
Error loading meta data for 'Microsoft.Extensions.FileProviders.Embedded.2.0.1'
hexadecimal value 0x1C invalid character
Every time I attempted to download a different nuget package or restore old packages I would see this error. I also saw the other errors such as:
type or namespace system could not be found
What worked for me:
opened the filepath that the error said the bad metadata was in, which for me was C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.extensions.fileproviders.embedded\2.0.1
Then, I put the contents of that folder into another folder I named "hiding".
Then, I went back to the nuget package manager and tried to install a package, hoping to have the SDK restored. IOt worked successfully, and all my other errors were gone as well, and the fresh new project runs as it should!
The problem for me occurred when running my Visual Studio as Admin with a separate user-- I had created a Git Repo with the source files in the user documents of my normal account. When I created a new solution in that folder the above errors occurred. Try creating your project in a different place and see if the error still occurs.
I was facing the same issue when I created a new project (.net Core 2.2) in VS2019.In my case there was an Azure package which was creating the problem.I uninstalled it and the project started working fine.
Run mentioned below command to uninstall the package.
Uninstall-Package Microsoft.VisualStudio.Azure.Containers.Tools.Targets -Version 1.7.10
I had the same problem. I cloned a github project and this error came. So I deleted the cloned project and then I cloned the project again and it worked fine.
I'm trying to build a console app to test out redis/mono communication. I've been hitting a brick wall using Monodevelop 4.0 (Xamarin Studios)+Nuget Port to work with ServiceStack.Redis on mac os.
All the solutions I've found online only say, change the ".Net 4.0 Client Profile" into ".Net 4.0 full" on visual studios. I haven't found a related function on MonoDevelop, not even sure if such an option exists. So no help there.
The error I am getting is:
"The type or namespace name `RedisClient' could not be found. Are you missing a using directive or an assembly reference?"
The screencap below shows the missing references, even though it is clearly in the reference folder :(. It is very puzzling.
Has anyone had a similar problem? Any help would be appreciated.
I think this is generally an issue with lagging version numbers on Mono.
For example, here's an example that can reproduce the issue:
Your ServiceStack.Redis is compiled against ServiceStack.Interfaces -> 3.9.45.
But you've actually pulled the latest 3.9.48 versions of:
ServiceStack.Interfaces 3.9.48
ServiceStack.Common 3.9.48
ServiceStack.Text 3.9.48
Mono will have problems forwarding old ServiceStack references 3.9.45 to 3.9.48.
So, recompiling from source will resolve the issue.
Or, ensure all your references are using the same version number by opening up all ServiceStack.*.dll (as you've done) and ensure there are no lagging version number references.
Similarly, I had a problem with ServiceStack.Logging.NLog compiled against 3.9.44 packages which lead to various TypeLoadExceptions on Mono when the head version of ServiceStack.* is 3.9.48.
So after hair tearing fighting with the MonoDevelop IDE and nuget. I just resorted to building the Servicestack.redis from source in MonoDevelop, and copied over the output DLLs. This worked without a problem.
It seems either that monodevelop doesn't like the Dlls from nuget, or that the nuget port has some bugs with DLl references. Either way, I don't know the specifics, but there is a solution around it by building servicestack components from source in MonoDevelop.
I was having this same issue with Xamarin Studio 4.0.12 + NuGet Port running against Mono 2.10.9.
Yesterday I decided to try to get OrmLite working & when I went to add the package, I saw that there were ServiceStack updates available (to version 3.9.66.0 from 3.9.63.0). Installed the updates and added the OrmLite package and I started getting the same error...
"The type or namespace name 'OrmLiteConnectionFactory" could not be
found. Are you missing a using directive or an assembly reference?"
The weird part was Intellisense was working (I could fully qualify OrmLiteConnectionFactory in the IDE and it would find it fine) but it would not build. Just like you, I also saw in Assembly Browser that my ServiceStack DLLs were referencing previous versions of some of the other ServiceStack projects.
Upgrading to the latest Mono release (3.2.3 atm) solved the issue for me. Hallelujah! Not sure why I was using Mono 2.10.9 to begin with.
I just installed NServiceBus, started to go through the getting started sample, but when I tried to create a MVC endpoint as suggested here http://docs.particular.net/samples/web/ I got an unexpected exception stating that this product type is not supported by this installation, all other endpoint type work.
Any ideas on how to solve this?
Cheers
It seems like you don't have the ASP NET MVC 3 project type installed on your environment.
Please try installing it from http://www.asp.net/mvc/mvc3.
If you have tried to install it using the Web Platform Installer Tool, be sure that you installed the right version and product (I use to make mistakes with so many similar named products).