namespace not found!

c# .net reference using

13,657

Solution 1

Make sure that

The ConsoleApp project has a reference to the Foo.Common project (do not browse for Foo.Common.dll),
the file contains a using directive for the namespace in which CommonClass is declared, and
CommonClass is declared as public.

So your files should look like this:

CommonClass.cs in Foo.Common project:

namespace Foo.Common
{
    public class CommonClass
    {
        public CommonClass()
        {
        }
    }
}

Program.cs in ConsoleApp project:

using Foo.Common;

namespace ConsoleApp
{
    public class Program
    {
        public static void Main()
        {
            CommonClass x = new CommonClass();
        }
    }
}

Solution 2

Ensure that under your project settings, the target framework is set as .NET Framework 4 and not .NET Framework 4 Client Profile. I got this same behavior when it was set to Client Profile and it was fixes as soon as I set it to just the regular .NET Framework 4.

13,657

Author by

Foo Bar

Updated on June 23, 2022

Comments

Foo Bar almost 2 years
I created a solution called Foo. Added a class library called Foo.Common Added a console app to call the library code from called ConsoleApp.

I referenced the Foo.Common from ConsoleApp and typed :
```
using Foo.Common;
public class Program
{
    CommonClass c = new CommonClass();            

    static void Main(string[] args)
    {
    }
}
```
and get this back :

Error 1 The type or namespace name '**Foo**' could not be found (are you missing a using directive or an assembly reference?) Z:\Foo\Solution1\ConsoleApplication1\Program.cs 3 11 ConsoleApplication1

Why am i getting this?

what s going on?
Foo Bar almost 13 years

I dont have a Foo namespace. I have Foo.Common
Foo Bar almost 13 years

and i added Foo.Common library as a reference.
Jesus Ramos almost 13 years

so it looks like namspace Foo.Common { public class CommonClass ... } in the other solution?
Jesus Ramos almost 13 years

When you type does the autocomplete show Foo.Common? If anything try Foo.Common.CommonClass = new Foo.Common.CommonClass()
Foo Bar almost 13 years

it s exactly like this. but when i compiled, i m getting compilation error as above.
Foo Bar almost 13 years

That s exactly how I added the reference via Projects tab.
Foo Bar almost 13 years

Ok the errro was due to Project was in .net 4 client profile in the settings.
Feidex almost 13 years

It is perfectly valid to have a using directive inside a namespace declaration. There is no ambiguity with a using statement.
Carson63000 almost 13 years

Indeed, not only is it valid, but some people strongly recommend it, this question has some good information. Although, having one using inside the namespace and one outside is surely not good style!
mletterle almost 13 years

Yeah, I realized that shortly after I posted, it's really useful for doing namespace aliasing. Still, I thought it might be related, guess it was the .net 4 client profile thing though.
Samvel Siradeghyan over 11 years

@Foo Bar you last comment must be answer :)))
Matt almost 11 years

@FooBar please make your comment the answer :)