CODEWITHSUNDEEP
c#classnamespaces
IneedHelp
IneedHelp

Reputation: 1758

Why am I forced to use full namespaces?

I have created the following class:

using System.Windows;
using System.Windows.Input;
using MyUtils.MyArgParser;

namespace MyUtils.MyImplement
{
    public static class ImplementExitOnEscape
    {
        #region ImplementExitOnEscape

        public static void Implement(Window window)
        {
            window.KeyDown += Window_KeyDown;
        }

        private static void Window_KeyDown(object sender, KeyEventArgs e)
        {
            var window = sender as Window;
            // Close window when pressing the escape key.
            if (e.Key == Key.Escape) if (window != null) window.Close();

            var optionX = MyArgParser.MyArgParser.GetOptionValue("optionX");
        }

        #endregion //ImplementExitOnEscape
    }
}

Why am I forced to use the full name space for the MyArgParser class in var optionX = MyArgParser.MyArgParser.GetOptionValue("optionX"); instead of just MyArgParser.GetOptionValue("optionX");?

using MyUtils.MyArgParser; gets ignored. having it there or not wouldn't make any difference, the compiler still forces me to use the full namespace.

I find this weird because it is not happening everywhere. For example, I am not required to use the full namespace in the file where the entry point of my application is defined.

Upvotes: 2

Views: 2202

Answers (4)

Jeppe Stig Nielsen
Jeppe Stig Nielsen

Reputation: 61912

You have your using directives outside your namespace declaration. The compiler searches for a type or namespace in these locations, in this order:

  1. MyUtils.MyImplement.ImplementExitOnEscape (nested types inside the current type)
  2. MyUtils.MyImplement (types or namespaces in current namespace)
  3. MyUtils (types or namespaces in "next" outer level)
  4. the null namespace or global namespace (types or namespaces)
  5. System.Windows, System.Windows.Input, and MyUtils.MyArgParser that you have usings for (types or namespaces)

You entered MyArgParser.<something>.

In (3.) a match is found, and that is the namespace. Only in (5.) would your using matter. So MyArgParser refers to the namespace, not the type.

If you had put your usings inside the namespace block, things would have been different, see an answer of mine in another thread.

Upvotes: 1

akton
akton

Reputation: 14376

The problem is you have a class with the same name as its namespace, meaning the compiler cannot differentiate between MyArgParser in MyArgParser.GetOptionValue being a namespace or a class.

It may or may not force you to use the full namespace due different using statements at the top of each file or a field or variable whose name clashes with the class name. See Eric Lippert's Blog post (and parts 2, 3 and 4) on the subject for more information.

See How to avoid having the same name for a class and it's namespace, such as Technology.Technology? for more discussion on this.

Upvotes: 6

muniro
muniro

Reputation: 21

There could be few reasons:

  1. Conflict with another name

  2. Your class could be under yet another name.

Use Ctrl+J+K, and search for your class. See if VS finds it. If not, then it may be because of refercence issues. Do you need to add a reference to that library?

Upvotes: 0

Erre Efe
Erre Efe

Reputation: 15557

var optionX = MyArgParser.MyArgParser.GetOptionValue("optionX");

You class is named as your namespace, so to distinct between them you need to explicitly fully reference it.

To solve it, either change your MyArgParser namespace to (for example) MyArgParserNS and you can use it directly

using MyUtils.MyArgParserNS

And then:

var optionX = MyArgParser.GetOptionValue("optionX");

Or, well, fully reference it.

Upvotes: 7

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