I'm trying out making websites with C# and I have a problem with my SQLite DB.
I've seen that you can Display every element of a DB with a gridview and it is automatic. But I cannot make it work with SQLite.
So I searched to find a solution to my problem and I found an article going through the process but it's a bit outdated.
He installed the System.Data.Sqlite(x86 x64) and I was trying to find that one but I couldn't find it.
But I found System.Data.Sqlite.x64 and I assume that it's the same and that it just doesn't support x86 anymore.
Nuget
Afterwards he opened the Entity Data Model and he had 2 options instead of 4 as me and also not the same ones.
I clicked on the EF Designer from database cause it had somewhat the same description as the one he clicked on.
Entity Data Model Wizard
After I click next I go to the Choose Data Source but I don't have an option for SQLite.
Choose Data Source
If I'm doing something wrong or I didn't understand something please correct me.
Thank you for your time!
Seems like this was raised with Visual studio community: sqlite-data-connection-not-appearing-in-server-exp
Solution proposed is the following:
Hi Robin,
It appears the developer that created the SQLite/SQL Server Compact Toolbox also has a solution to support VS 2017. See https://github.com/ErikEJ/SqlCeToolbox/wiki/EF6-workflow-with-SQLite-DDEX-provider
Or you can get the extention from the marketplace here
Works with
Visual Studio 2012, 2013, 2015, 2017, 2019
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" />
I am working on a Visual Studio project that uses ASP.NET/C# with LinqToSql.
All has been going fine, until some changes were made to one of the database tables.
After that, the Table in question was removed from the DBML database diagram, and the new version added back in using the Server Explorer.
Trouble is, VS2013 still does not see the new fields, and will not compile if I reference them. The new table structure is clearly visible in the DBML database diagram.
Right click on your file in solution explorer and select Run custom tools and see if it is getting updated.
Rebuild your project and you should see the changes.
I cannot find the Entity Data Model under the 'Data' tab when adding a new item.
I have looked at several questions and answers, information on this and none of the solutions have worked.
I have repaired, uninstalled and reinstalled, installed the EF Tools package manually and tried uninstalling all VS related programs. I have also tried creating several new projects, Class Libraries, Web Projects under different .NET frameworks and it isn't there.
Main project: Visual Studio 2012, Class Library Project .NET 4.0
I updated Visual Studio 2012 using this link:
http://www.microsoft.com/visualstudio/eng/downloads#d-visual-studio-2012-update. After this update, the "Entity Data Model" option was added to the data tab.
The new Entity Data Model in VS 2012 by default uses T4 templates (.tt) files instead of former custom tool for code generation. The generated context is also based newer DbContext API instead of ObjectContext API used by Visual Studio 2010 (that is the reason why it doesn't have the method - the equivalent method in DbContext API is Set<T>). Both T4 and DbContext API are currently recommended approach for using EF.
I don't have VS 2012 on my current machine but what you can try is to delete both .tt and turn on the old generation as described in .Desinger.cs.
Edit: You may try to Re-install VS2012 and/or repair it. That should fix this issue. In addition, look at the release version of your VS2012.
Another suggested solution to re-install and reason why this happens - Unable to add Entity data model to a Visual Studio project
The accepted answer from here solved the problem in my case:
http://www.datazx.cn/Fv7p5a/xw-US/oaax2pu/2q7xs6/d8x6rssc-b4mt-fsix-bc6c-ct8mf8d6fsbc23rsdfd.html
I finally figured it out. I ran EFTools.msi from a C:\ProgramData\Package Cache\ subfolder, which only allowed me to 'uninstall' or 'repair'. I tried repair, but I get the same problem, so I did 'uninstall', then ran it again and it allowed 'install'. After this install, I can now add Entity Data Models.
Also, the accepted answer in the "Missing Entity Framework Template in Visual Studio 2012 Express for Web" threat on forums.asp.net suggests that repairing Entity Framework Designer for Visual Studio 2012 enu via 'Start -> Control Panel -> Programs and Features' might work as well (I can post only two links with my current 1 point StackOverflow reputation, so I won't provide the exact source).
Another possible solution:
My Problem was: Visual Studio is installed on Drive D:\, whereas the Entity Framework Installer placed the Package in c:...\VisualStudio 10.0\Common7....\ItemTemplates folder. --> Copied the AdoNetEntityDataModelCSharp.zip to drive d: and ran devenv /installvstemplates. This fixxed it for me. Edit: Also had to copy Various DLLs from IDE folder, PrivateAssemblies and PublicAssemblies. then run devenv /ResetSkipPkgs
http://social.msdn.microsoft.com/Forums/en-US/c059069b-eae4-48b4-a06e-ffd5f186077b/adonet-data-entity-model-template-missing-in-vs-2010-ultimate?forum=adodotnetentityframework
I also installed VS in a non-default path (different disk partition), so it indeed may be one of the potential causes of the problem.
You can right-click the designer surface and choose the model browser; Here is the only way to activate the Model browser in solution explorer.
The Model browser is included in VS 2012 recommended settings during installation.
I've reinstalled my laptop - Windows 7, VS2010, VS2010 SP1, SQL2008 and SQL2008 SP2.
I've also done windows updates - no updates available from update window anymore
The issue I've is: When I double click on the EDMX file it gets directly in to the XML. Why is that?
I don't get any error....
I can't do update from Database or add entities from Database etc....
I googled and found you should do open with and choose XML and then close XML and double click again. I've tried several options (open with ) and I don't get the UI Designer for my Entity Framework (edmx ) file.
I clicked on the properties of the file (*.edmx)
and I see Cusotmtool: EntityModelCodeGenerator and build action : EntityDeploy
I then right clicked on EDMX and choose 'Run Custom Tool" and then I receive this error
"cannot find custom tool 'EntityModelCodeGenerator' on this system."
I checked VS2010 and VS2010 SP1 is installed. I did again install from DVD and choose REPAIR and I still have this problem....
so what could be problem?
thanks
you had unchecked some of recommended features while installing the Visual Studio. Just Reinstall the visual studio to configure the features. after installation open the .edmx file with the "ADO.Net Entity Framwork designer".
Try devenv.exe option /resetskippkgs, then solve the error.
The question is about VS2010, but if you're looking at the same problem on a newer Visual Studio (e.g. VS2013), you probably need to reapply the latest VS update (worked for me) or reinstall VS.