How to fix errror CS0246 with a database connection string

Question

How to fix errror CS0246 with a database connection string

Michael Tadyshak 80

I have a connection string defined in App.Config as type NorthwindEntities. The type NorthwindEntities is used in source file CustomerViewModel.cs but gets an error CS0246 (Type or namespace name cannot be found).

Erland Sommarskog 121.9K Reputation points MVP Volunteer Moderator

2024-02-18T11:10:04.58+00:00

This post only had the SQL Server tag. I added the C# tag, as it appears to be a client-side problem. C# people may want to refine the tag list further.

Michael Tadyshak 80

Here is the connection string in App.config:

  <connectionStrings>
    <add name="NorthwindEntities" connectionString="metadata=res://*/NorthwindModel.csdl|res://*/NorthwindModel.ssdl|res://*/NorthwindModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=localhost\SQLEXPRESS;initial catalog=Northwind;integrated security=True;encrypt=False;trustservercertificate=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>

Here is the CustomerViewModel.cs file:

using System;
using System.Windows.Forms;
using System.Data.Entity;
namespace MVVMDemo
{
    public class CustomerViewModel : IDisposable
    {
        private NorthwindEntities db;
        public CustomerViewModel() => db = new NorthwindEntities();
T

he spelling of NorthwindEntities is the same for both.

Accepted answer

1 additional answer

Your answer

Erland Sommarskog 121.9K Reputation points MVP Volunteer Moderator

2024-02-18T11:10:04.58+00:00

This post only had the SQL Server tag. I added the C# tag, as it appears to be a client-side problem. C# people may want to refine the tag list further.
Michael Tadyshak 80 Reputation points

2024-02-18T18:08:35.2233333+00:00

Here is the connection string in App.config:

<connectionStrings> <add name="NorthwindEntities" connectionString="metadata=res://*/NorthwindModel.csdl|res://*/NorthwindModel.ssdl|res://*/NorthwindModel.msl;provider=System.Data.SqlClient;provider connection string="data source=localhost\SQLEXPRESS;initial catalog=Northwind;integrated security=True;encrypt=False;trustservercertificate=True;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient" /> </connectionStrings>

Here is the CustomerViewModel.cs file:

using System; using System.Windows.Forms; using System.Data.Entity; namespace MVVMDemo { public class CustomerViewModel : IDisposable { private NorthwindEntities db; public CustomerViewModel() => db = new NorthwindEntities(); T

he spelling of NorthwindEntities is the same for both.

Answer 1

Hi,@Michael Tadyshak .Welcome to Microsoft Q&A .

The error CS0246 ("Type or namespace name cannot be found") typically occurs when the compiler can't find a reference to the specified type or namespace. In this case, it seems like the NorthwindEntities type is not recognized by the compiler.Here are a few steps to troubleshoot and resolve the issue:

Check Namespace: Ensure that the NorthwindEntities class is defined in the correct namespace. In your code snippet, you've shown the CustomerViewModel class in the MVVMDemo namespace. Make sure that NorthwindEntities is also in the same or a properly imported namespace.

namespace MVVMDemo
{
    public class NorthwindEntities
    {
        // ...
    }
    public class CustomerViewModel : IDisposable
    {
        private NorthwindEntities db;
        // ...
    }
}

Check Entity Framework Reference: Ensure that your project has a reference to Entity Framework. Right-click on your project in Visual Studio, go to "Manage NuGet Packages," and make sure Entity Framework is installed.

Check Project References: Verify that the project containing CustomerViewModel.cs has a reference to the project or assembly where NorthwindEntities is defined. If NorthwindEntities is in a separate project, add a reference to that project.

Clean and Rebuild: Sometimes, build artifacts can cause issues. Clean your solution (Build > Clean Solution) and then rebuild it (Build > Rebuild Solution).

Check for Typos: Ensure that there are no typos in the class or namespace names. C# is case-sensitive, so NorthwindEntities must exactly match the case used in its definition.

Check Configuration File: Ensure that the App.config file is in the correct location and properly configured. Check that the NorthwindEntities connection string is defined in the correct project.

Restart Visual Studio: Occasionally, Visual Studio can have quirks. Try restarting Visual Studio to see if the issue persists.

Check Project Build Order: In the Solution Explorer, right-click on the solution and go to "Project Build Order." Ensure that the project containing NorthwindEntities is built before the project containing CustomerViewModel.

If the problem persists, could you provide minimal example code and steps without private information that can reproduce the problem.Did you follow some documented steps? If so, could you share a link to the document?

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Q&A Assist

AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

To fix error CS0246, you need to ensure that the namespace or type name is correctly referenced in your code. In this case, the error is occurring because the type NorthwindEntities cannot be found. To fix this, you should check that the namespace containing NorthwindEntities is correctly referenced in your code. You should also ensure that the connection string in your App.config file is correctly defined and that it matches the name used in your code.

References:

Michael Tadyshak 80 Reputation points

2024-02-19T17:08:22.8533333+00:00

Wow! That was a very helpful response! Here is what happened. The tutorial selected only the Customer table, but I selected several other tables as well. Then I decided that that would make it difficult to follow the tutorial so I deleted lines from an auto-generated file NorthwindModel.context.cs. Bad thing to do!!! That corrupted the file and class NorthwindEntities was no longer defined.
Then I started playing with the design surface where you can diagram your own database and somehow that caused the auto-generated file to be re-generated and suddenly the problem went away.

Share via

How to fix errror CS0246 with a database connection string

1 additional answer

Your answer