Can't compile with 'using' inside the namespace

Question

I have the following code:

using Data;
using MyProject_API.Models.ViewModels;
using System.Linq;
using Utilities.Web.Authentication;

namespace MyProject_API.Services.EmailTemplates
{

    /// <summary>
    /// Defines the <see cref="EmailTemplatesSearch" />
    /// </summary>
    public class EmailTemplatesSearch
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="EmailTemplatesSearch"/> class.
        /// </summary>
        /// <param name="dataContext">The dataContext<see cref="DataContext"/></param>
        /// <param name="user">The user<see cref="MyProjectIdentity"/></param>
        public EmailTemplatesSearch(DataContext dataContext, MyProjectIdentity user)
        {
            _db = dataContext;
            _user = user;
        }

I've cleaned the code with help of CodeFormatter and get the following code:

namespace MyProject_API.Services.EmailTemplates
{
    using MyProject_API.Models.ViewModels;
    using System.Linq;
    using Utilities.Web.Authentication;

    /// <summary>
    /// Defines the <see cref="EmailTemplatesSearch" />
    /// </summary>
    public class EmailTemplatesSearch
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="EmailTemplatesSearch"/> class.
        /// </summary>
        /// <param name="dataContext">The dataContext<see cref="DataContext"/></param>
        /// <param name="user">The user<see cref="MyProjectIdentity"/></param>
        public EmailTemplatesSearch(DataContext dataContext, MyProjectIdentity user)
        {
            _db = dataContext;
            _user = user;
        }

As you can see, CodeFormatter looses using Data;. I've tried to add using Data; to the list of usings, but the code can't be compiled, DataContext which is in Data namespace can't be found. I fixed the problem moving using Data; outside from namespace, but it looks like a crutch. DataContext is defined like a

namespace Data
{
    public class DataContext

• Why CodeFormatter looses using Data;?
• Why using Data; doesn't work inside the namespace?

I've searched for similar questions: LINQ to SQL Designer Bug , Should 'using' directives be inside or outside the namespace? , etc., but i still don't understand how to solve my issues

Answer 1

The solution was already given in the first comment by maccettura.

If you read my answer to the thread "Should 'using' directives be inside or outside the namespace in C#?" which you already linked, you should understand that when you have using Data; inside your declaraion namespace MyProject_API.Services.EmailTemplates { /* ... */ }, any namespace:

MyProject_API.Services.EmailTemplates.Data

or

MyProject_API.Services.Data

or

MyProject_API.Data

would match before the namespace Data you actually want.

C#'s way to get around that, is to use the global alias, like this:

namespace MyProject_API.Services.EmailTemplates
{
    using global::Data;  //  <--- global alias used
    using MyProject_API.Models.ViewModels;  //  <--- unless you have other name conflicts, 'using Models.ViewModels;' is sufficient now
    using System.Linq;
    using Utilities.Web.Authentication;

    // your classes here
}

This will make your using point to the namespace you want. And with that, it will no longer be an unused using directive, and code formatting will no longer "lose" (i.e. remove) it.

The tool you used for moving usings from the outside to the inside, apparently was not smart enough to add the needed global::.