I have an MVC5 application which I'm trying to run offline. I installed VS2017 offline but when I try to build the project it throws multiple errors relating to it missing all the .NET assemblies and dlls. When I try to add these assemblies they're not available to be added. Anyone please help.
PS: there's NO internet on the machine.
I also have that problem from time to time. What usually helps is to do a dotnet restore. This is different to running restore from the solution explorer within VS, you have to do it through the command line. In order to execute it, you need to have the .NET Core SDK installed. dotnet restore is usually very good at fixing some project problems such as corrupted .json files that VS creates behind the scenes and I would guess that it is able to repair those files without internet connection, but I haven't tried.
Try cleaning and rebuilding your solution. I had this issue and something went funky with my dll's.
It's obvious omnisharp error same as mine. I changed omnisharp path version from c# extension(c# > unistall > install another version) and reopened to vscode. It worked for my project. All error has gone.
I have two different projects that use Entity Framework, to generate my migrations I use the commands Add-Migration name and Update-Database.
Now, for some reason, the first project always makes sure that my project is built with the latest code by issuing a build after every one of these commands that I do inside Pacakge Manager Console.
This is what I see as the correct way.
But my second project, despite being very similar, it never do that build automatically as the first one does.
So If I need to generate a new migration, I first run a build, then run Add-Migration name, then build again, then run Update-Database.
Is there a option somewhere that I'm not aware that enables or disables that behavior?
Ps. my visual studio version is 2017 Enterprise
Thanks
First I would love to comment instead giving an answer but I can't yet.
In your startup file in the first project do you have something similar to this?
dbContext.Database.EnsureCreated();
Or
dbContext.Database.Migrate();
If the answer is yes that's maybe why in one of your projects when you start it the project update the database.
So I made a .net core web api project and pushed it to a git repo. After pulling down the repo and attempting to run the IIS express server locally, I'm getting the error
Unable to run your project. The "RunCommand" property is not defined.
If I create a new web api project on this computer, it works fine. So it's only the project that I've pulled from git that won't work. Is there some command I need to run to make it...I don't know, update for this computer?
I've done almost nothing to this project. I added one new controller and that's it. Everything else is the default project settings.
The exact project is:
Templates -> .NET Core -> ASP.Net Core Web Application
.NET Framework 4.5.2
Edit: I've compared the new project I created with the one I cloned and everything looks the same. So I'm baffled.
Make sure that the OutputType of the project is set to Exe and that the project file starts with <Project Sdk="Microsoft.NET.Sdk.Web">.
Both are important to give VS:
The command to run when executing the project
Turn on the capabilities to generate and use a Properties/launchSettings.json file.
If your app doesn't launch, i suggest deleting a Web.config file (if exists) and Properties/launchSettings.json, then re-open the solution.
I needed to delete the
bin, obj, and .vs directories.
I just need to ignore those directories with gitignore and I won't have this issue anymore.
I have tried all the solution like repairing the VS 2013 but no use.
when you create a controller by right clicking on the Controller folder and you add the controller, then you right click in the Action of the newly created controller and select Add View, it happens right then, when I try to create a view. Its not a new project, its an existing project.
For me the error had to do with the fact that I had a project in my solution that was a .NET Core project library and was referenced in the project that housed the DbContext.
Removing - or I guess changing the type - the .NET core library resolved the issue
I had this issue on my VS2017 and i solved it by doing this:
Go to C:\Users\username\AppData\Local\Microsoft\VisualStudio\15.0_7fca0c70 and you will see a folder named ComponentModelCache just renamed it like _ComponentModelCache or anything else,visual studio will create this folder again.
One thing to notice under VisualStudio folder name 15.0_7fca0c70 can be differenct it depends on your VS version. Now you are good to Go. Hope it helps somebody.
Deleting the .vs folder inside the solution directory worked for me.
Visual Studio 2019/2022:
Clean Project
Rebuild Project
Close and reopen Visual Studio 2022
If not works -> update Microsoft.VisualStudio.Web.CodeGeneration.Design NuGet package to latest and try again.
I have the same error in Visual Studio 2017 I fix it by this solution :
1 - if you use any database , must be install all drivers (I mean Nugget packages and etc...)
(I use MySql db so i must I first install MySql installer and install MySql,Data,EntityFramWorkCore)
2 - I Update My Visual Studio with Visual Studio Installer (your must be search visual studio installer in start and run it next update (don't need to add any new component or codes only select Update Button ) )
It work for me , I hope this will be help you
Tried all the following answers with no luck:
Solution Clean
Deleting old migrations
Close and reopen Visual Studio
Delete Visual Studio temp Components folder
This one worked:
Uninstalled the package (Microsoft.VisualStudio.Web.CodeGeneration.Design) and re-installed it from Package Manager Console.
My environment:
Visual Studio 2019 -
Razor Pages - .Net Code 2.2 - Windows 10
My issue (which specifically has the 'Object reference not set to an instance of an object.' error) was resolved by changing some of the projects in the Solution from .net standard 2.0 to .Net Framework 4.8.
This was inspired by the answer by Timo Hermans above and having tried the main answer deleting the ComponentModelCache which had helped previously.
In the project I was performing the scaffolding in I traced projects that linked to the Model I was using and changed them to net48. I did not have to change them all, so not entirely sure which projects but I started with the Models project and then followed other key projects changing them back to net48 until the scaffolding worked again.
Hope this might be of use to someone because it was driving me made!
Simple steps that worked for me like charm
Remove the project from the solution
Use Add Exisiting project to add the same project back
Build and Add View now, it works
This Error is related to Entity Framework Data Model ..
for solution Perform these Steps...
Delete your Entity Framework Data Model.
Again Regenerate the Model from Database Design.
then Rebuild the Solution ... and Enjoy Coding .
Try installing the Windows Management Framework:
https://www.microsoft.com/en-us/download/details.aspx?id=34595
Restart the PC after installing.
I have the same error, I just removed only read permission in the folder where is the web project
Or maybe like me you didn't notice the 'Data context class' field was blank. Oops. If so, simply select your data context class and try again.
There really should be a better error for this scenario.
Removed the error by starting a whole new project because I had initially referenced a Class Library that housed the data access and business logic code for my project.
I have the same error in vs2017 on windows10, pls try to run vs as admin, hope it'll work for you too.
Although I had not noticed right away that my ability to add Controllers ceased when I added another project to the solution, I eventually caught on that this was a repeatable cause for my disruption. This is what worked for me:
In addition to the .Net Web App project where I was adding Controllers, I had added another project to the solution- this causes the problem for me.
I unloaded the new project and then tried the Add Controller step again. This time it worked.
I then reloaded the new project and continued to work
It took me a couple of hours to diagnose and solve this. Maybe it helps someone else to not spin wheels this long!
Instead of renaming, I left DefaultController then renamed it after it was created.
I had a Standard .Net v2 class library beside my main ASP.Net MVC project which targeted .Net Framework v4.6.2 and after several controller creation suddenly the mentioned error came up.
So I :
Removed references to the class library
Deleted class library entirely
Created another one with .Net Framework v4.6.2
and the problem solved.
I had the same error, I just closed the web.config file and its working now.
Same error in VS2019, looks like I'd missed a project reference after collapsing three projects into a single solution.
I'd referenced the API and class library in my UI project so I could use the db context (in the API project) and class files for scaffolding, but failed to reference the class library in the API project (it'd previously been added as a NuGet package) and it gave me this error message.
Uninstalled the package and added as a project reference and my issue seems to be fixed.
I just removed the space** from DATA CONTEXT CLASS. worked for me.
Add View > Data Context Class >
REGMVCEntities**(REGISTRATION.Models)
For me I downgrade My packages from 5.0.5 to 5.0.4 all thinks work fine
In the end, my problem was that the project to which I was trying to add a scaffolded item was on a network shared drive / mapped drive. Moving the project to a local disk fixed my problem.
VS 2013 Update 5
Rebuild your project and check the warning messages. Try to fix those and try again!
Just change your ConnectionString in Web.Config file From
<add name="xxx" connectionString="Data Source=xxx;initial catalog=xxx;Persist Security Info=True;User ID=xxxx;Password=xxxx;MultipleActiveResultSets=True" providerName="System.Data.SqlClient" />
To
<add name="xxx" connectionString="metadata=res://*/EFMOdel.csdl|res://*/EFMOdel.ssdl|res://*/EFMOdel.msl;provider=System.Data.SqlClient;provider connection string="data source=xxxx;initial catalog=xxxx;persist security info=True;user id=xxxx;password=xxx;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient" />
Recently while working on a webp project within Visual Studio 2013, I updated a website that was using Entity Framework Database First, and wanted/needed to update to EF 6. Upon doing so I also needed to update the EF EDMX designer in order to support EF 6. The upgrade went perfectly fine within the web app I was working on.
I later opened a previous web project, one which does not make any use of EF, and was greeted with the application error message "Could not load file or assembly 'System.Data.Entity.Design'." I thought it was odd, that I was getting this error in a project that has 0 references or utilization of EF in anyway. Thinking it was something weird in VS I closed it and attempted to reopen the project and run it, but again the same error. So I then added System.Data.Entity.Design to the references list and I STILL couldn't run it, so I changed the properties to "Copy Local: True" and it finally worked.
I have been encountering this issue in all web projects I open and create, unless I already fixed the issue with the Copy local change. I figured that something with the update must not have occurred correctly and therefore not installed the EF DLLs to the GAC so I tried using gacutil to make the install using the command gacutil.exe /i System.Data.Entity.Design.dll but was presented with error message below.
Does anyone have any suggestions on how to resolve this issue? While it's not project breaking, it is rather frustrating whenever opening or creating projects to add an unnecessary DLL to the project simply to get it to run and debug.