C# not recognizing SQLConnection even when using "using System.Data.SqlClient;"

Question

Here is the code that I'm looking at -

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;

namespace CSharpPracticeProject
{
    class Testing
    {

        public static void main()
        {
            SqlConnection myConnection = null;
            int x = 25;
            Console.WriteLine(x/4);
        }
    }

}

Error message - 'The type or namespace 'SqlConnection' could not be found.

It seems like other posts seem to solve the issue with the import, so Im just not sure what the issue is. This is Microsoft Visual Studio 2017.

Is this .NET Framework, Standard, or Core? Can you clean and rebuild? — ProgrammingLlama
– ProgrammingLlama, Commented May 8, 2018 at 13:45
Do you have the "Target framework" (project properties) set to .NET Framework X Client Profile ? — Igor
– Igor, Commented May 8, 2018 at 13:47
By references do you mean the using keyword? This is Microsoft Visual Studio 2017, and adding using System.Data doesnt make it be recognized. Even if I enter the entire pathname when declaring the variable it isnt recognized. — user9758771
– user9758771, Commented May 8, 2018 at 13:53
@user "References" are links to other libraries. In .NET Framework projects this appears under "References" in the Solution Explorer. In .NET Core projects, it appears under "Dependencies" in the Solution Explorer. — ProgrammingLlama
– ProgrammingLlama, Commented May 8, 2018 at 13:55

ProgrammingLlama · Accepted Answer · 2018-05-08 13:57:17Z

20

I'm going to assume that you're using .NET Core, since it should work out the box with the code you have if you're using .NET Framework.

In .NET Core, you need to add a reference to System.Data.SqlClient via NuGet:

Select Tools | NuGet Package Manager | Manage NuGet Packages for Solution
Click "Browse"
Type System.Data.SqlClient and hit return
Select System.Data.SqlClient by Microsoft
On the panel on the right, check your project.
Click Install
Click OK to the next box that comes up.

Your code should now work.

If you're using .NET Framework, which seems unlikely given the problem you're facing, you can check if you have System.Data referenced by right-clicking "References" in the Solution Explorer, selecting "Assemblies" and ensuring that "System.Data" is checked.

edited May 8, 2018 at 13:57

answered May 8, 2018 at 13:52

ProgrammingLlama

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2 Comments

user9758771 Over a year ago

Yes it is .NET Core, and I just did all of that and it worked. Thank you, I would have never thought of that on my own! Now I'll have to look at the differences between the two.

ProgrammingLlama Over a year ago

I'm glad I could help :)

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