I've been trying to set up EFCore with .NET6. When all my Models/Entities are inside a folder, the Initial Migration I ran removes all the dependencies(some) from the project and results in a failed build. But when I initially store my model in the root directory and run the same command it works.
This is the folder structure which causes the issue
Update
The last time I tried migrations worked if I placed the models and entities at the project's root, but now, even if I do, the same error happens. Please help me with this error. Thanks in advance.
Apparently, Visual Studio did not save the changes to the .csproj file on disk when I installed all the NuGet packages which resulted in the build failed error. This issue will not happen when we use visual studio to build the project because it will persist the changes to the disk when we do that but I used the CLI to build and run the migrations which resulted in this error.
(I refer Visual Studio Code as vscode)
I am working on Asp.Net Mvc project with .Net Core 2.2. If I do not modify the source code after I open vscode, I can debug/run the project within vscode without any problem. But after I modify the source code, if I debug, vscode gives me warning
Breakpoint warning: The source code is different from the original version. To allow this breakpoint to be hit: Add '"requireExactSource": false' to launch.json and restart debugging.
when i put a breakpoint and it comes disabled automatically. Also i can not see the last changes in the running project.
To be able to see the last modifications, I have to debug with Visual Studio once, and then if I debug/run the source code with vscode again, no problem till I modify the source code again.
How can I fix this situation?
Note: There is a similar question here but it says s/he can not use breakpoints since first run and the problem is related to dotnet path. My problem is completely different.
TL;DR check if vscode is building the right project/solution. dotnet build the main/entrance/single project does not build other dependency projects.
The root of the problem comes from tasks.json for me. The target for the build task was set wrong. It only builds a single project of a whole solution while the work is done on other projects of the solution.
My fix was modifying the building task to build the whole solution instead of a single project.
Debugging with Visual Studio was fixing the problem temporarly because it was building the whole solution which reflects the last modifications.
This SO answer is also related to this question.
Sample launch.json and tasks.json for .Net core.
I have created one new Migration in Visual Studio for my solution and then removed it (just remove files from Visual Studio). But now, when I try to do Update-Database it tries to apply that removed migration. I checked the whole solution and never seen any notification about that removed migration, it's really removed from solution. But package manager try to apply it. Why, where is it stored and how to remove at all?
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" />
If I do any changes to my EF 5.0 model, VS does not seem to see the changes. I have tried adding a new table, which shows up fine in the model, but then if I try to use it somewhere the table does not show up in intellisense and I can't use it.
I have also tried changing datatypes of a column, which again shows up fine if I look at the .edmx model file, but visual studio will still give me compiler errors on that field because I am trying to assign the incorrect datatype.
If I delete the EDMX completely, and recreate it, then the changes work fine. but it is tiresome to regenerate from database each time when I should be able to just "update model from database" and rebuild.
I have never had these problems with EF before. Does anyone know the cause or the fix to this problem?
Thanks.
First Build your Project and if it was successful, right click on the "model.tt" file and choose run custom tool. It will fix it.
Again Build your project and point to "model.context.tt" run custom tool. it will update DbSet lists.
If this is the bug with the edmx file located in a folder it is now fixed - download and install VS 2012 Update 1. You can get it from: http://www.microsoft.com/visualstudio/eng/downloads#d-visual-studio-2012-update
This is apparently a bug in the Entity Framework that the model does not get updated when your Edmx file is located inside a folder.
The workarounds available at the moment are:
Install VS 2012 Update 1 which should fix the bug.
If you are not in a position to install Update 1, you will have to right click on the model.tt T4 template file and click run custom tool. This will update the classes for you.
Hope that helps someone out there.
Link: http://thedatafarm.com/blog/data-access/watch-out-for-vs2012-edmx-code-generation-special-case/
I also had this problem, however, right-clicking on the model.tt file and running "Custom tool" didn't make any difference for me somehow, but a comment on the page Ghlouw linked to mentioned to use the menu item "BUILD > Transform All T4 Templates." which did it for me
Right click the .tt file and select "Run Custom Tool", that should update it:
You should have a <XXX>Model.tt file somewhere which is the T4 template that generates your model classes.
If it is in a different project, it will not update when you save the edmx file.
Anyway, try right-clicking on it in Solution Explorer and choosing Run Custom Tool
I searched for this answer because I had a similar situation in VS2013. In my case, I found that a simple "Clean Solution" cleared out all the old definitions.
Are you working in an N-Tiered project? If so, try rebuilding your Data Layer (or wherever your EDMX file is stored) before using it.
I've also experienced this problem with none of the classes being generated under the model.tt file. In my case it was down to issues with how I had built the DB in SQL2012. I'd set a column in a table to nullable that was also a foreign key and although I think you should be able to do this it caused a problem in EF5.
As soon as this was cleared and the diagram updated from the database they reappeared.
EF5 VS2013
After Changing the laptop When I updating Entity Framework model, stored procedures are not seen in code
What I have done to make this working
Update visual Studio 2012 Update 5 (Not Working)
Update/Modify from Programs (Not working)
After update stored procedures, build the project again then go to context.cs, right click and run custom tool (Not Working)
Doing RND (Someone says the issue is due to some permissions in MSSQL) But unfournately I have done alot of permission in MSSQL but (Not Working)
Install 2019 and run the project. Now everything works fine
Conclusion
Visual studio 2012 have a bug (bug is resolved in Update 1, 2, 3 and 4)
Change the Visual Studio version will resolve the issue
I had this problem in EF 6 using Visual Studio 2022. I tried all of the things here plus cleaning and rebuilding the solution, deleting the stored procedure out of EDMX and the database and re-updating, closing VS, and restarting my computer. None of those things worked. What ended up fixing it was simply opening the DTSEF.vb file. When I did that, Visual studio found the missing properties in the result object.