How to fix "namespace x already contains a definition for x" error? Happened after converting to VS2010

Specifically the error occurs in the Resources.Designer.cs:

> Error 2 The namespace 'ModulusFE' already contains a definition for 'StockChartX' Resources.Designer.cs 11 21 ModulusFE.StockChartX

I've googled this and am still quite confused. Does anyone know anything I might try?

I have tried rebuilding and cleaning, as well as renaming the Resources.Designer.cs file in hopes that it would rebuild, but no luck.

The top of the code says this:

// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:4.0.30319.225
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>

Any ideas whatsoever would be appreciated.

I had this happen to me about a year ago and I don't remember exactly what the root cause was, but there are two things you might try:

1. If it's an auto-generated file (as 'Resources.Designer.cs' tend to be), try deleting it and letting VS re-generate it.
2. Either separately or in conjunction with #1, select Show All Files in the Solution Explorer or open the solution folder in Windows Explorer - it could be that a version of the file somehow got excluded from the project and is therefor 'invisible' to VS but still makes it angry...

I've had this problem, too, and it was because I created a new namespace, but the parent namespace contained a class with the same name.

Looks like a bug in VS code's OmniSharp.

Solution for me was to execute command "Restart OmniSharp".

Just do:

• ctr shift P
• type "Restart OmniSharp" .. hit enter

This fixed it for me.

This is an old question but I didn't find the fix I used, so I've added it here.

In my case it was a namespace with the same name as a class in the parent namespace.

To find this, I used the object browser and searched for the name of the item that was already defined.

If it won't let you do this while you still have the error then temporarily change the name of the item it is complaining about and then find the offending item.

Unfortunately, none of the other answers helped. My problem specifically occurred in a WPF project.

The problem arose when I created a folder under the MainWindow folder, which effectively created a namespace something like ProjectName.MainWindow.Folder. Now, I believe because of some static designer code, Visual studio gets confused between the class MainWindow and the namespace Project.MainWindow.Folder . As a solution, I moved the Folder out of MainWindow. Looking at the Class View or the solution/project helps to recognize what namespaces and classes within them exist.

This just happened to me. What happened was that I duplicated a project that was originally under source control. Although I properly renamed everything, the file permissions on all the files were still set to read-only. When I started modifying some form controls, Visual Studio automatically created a Resource1 file because the original Resource file was read-only.

What I did to fix this was as follows:

1. allow write permissions on the project files.
2. deleted the original Resource file
3. Ctrl-A for all form elements, then Ctrl-X to cut them.
4. Save the form.
5. Ctrl-V to paste them all back.
6. Save the form.

I had to do this because the auto-generated code wasn't updating on it's own, so I "forced" it to update by making a change to the form. Not doing this left a bunch of code from form elements that no longer existed prior to changing the file permissions.

I had an xaml file with the following definition

<Window x:Class="mm2.Views"
   .etc..
/>

mm2.Views was the name of a namespace in my app.

To fix it, I correctly renamed the xaml object:

<Window x:Class="mm2.Views.RecordedTracks"
   .etc..
/>

I had a similar problem and resolved it by removing any copies/backups of the .cs file from the directory.

I had this same problem and it was due to naming a function in the code behind the same as my tool. Simple mistake but something to keep in mind as well.

I had a similar issue however found a different solution than what I have read. I came to my fix after reading P Walker's answer.

My issue happened when I named my resource file for Japanese language incorrectly. Long story short I was trying to create a Resource for Japanese but I accidentally named it localized.jp.resx. I then realized that the iso language code is ja not jp for Japanese. Once I changed the file name to localized.ja.resx and deleted everything that was in the designer file it fixed my problem.

This is what fixed my problem hopefully it helps someone else.

I came across a similar problem. After generating my database from an edmx file, I clicked 'save all' and 'build' and all the Types/Model classes that I created showed up in the error box. I researched why this happened and like your replies suggest, I thought it was something that was auto-generated.

However, solutions like deleting the auto-generated classes and re-generating them didn't work for me.

I eventually ran out of patience and decided I'd fix it another way. Since my script was saved, I just deleted the edmx file (and its reference in the web.config) and went back and created another one using "model from database" and didn't touch it after that.

Needless to say, I was pretty mad that it turned out like that.

Me too got this error, When I change my WPF project's Target Framework to Framework Version 4.0 Client Profile -> Framework 4.0. It's solved by itself.

The way I solved it was to remove all of the enums from the model browser, and then re-add them again. Somehow miraculously the tool regenerated everything perfectly and the error message went away (I'm using VS2012, FYI).

This may be a bit of an edge case, but we've run across this in our development environment from time to time. We had to setup a custom culture in Windows to support en-HK. Windows 8.1 now supports this culture natively as does Windows 2012 R2, but older machines need to have the culture created. Any machine that does not have this culture setup will get this error reported. The solution is to create the culture on the machine (We have a console app created for this purpose) and everything starts working again.

I had something similar to this happen in my WPF application. It arose when I was trying to do some cleanup by declaring a namespace that was more descriptive. The problem arose because I had named the namespace in the code-behind (or cs) the same as the Window class. The namespace in the code-behind should have the last section stripped (after the rightmost dot) and used to declare the class and instantiate it. Notice Win below:

xaml

<Window x:Class="FrameApp.UI.Invoice.Win" ...>

code-behind

namespace FrameApp.UI.Invoice
{
    public partial class Win : Window
    {
        public Win()
    }
}

An obvious oversight but it set me back at least an hour with all the errors that appeared.

I had the same issue just now, and I found it to be one of the simplest of oversights. I was building classes, copying and pasting code from one class file to the others. When I changed the name of the class in, say Class2, for example, there was a dropdown next to the class name asking if I wanted to change all references to Class2, which, when I selected 'yes', it in turn changed Class1's name to Class2.

Like I said, this is a very simple oversight that had me scratching my head for a short while, but double check your other files, especially the source file you copied from to ensure that VS didn't change the name on you, behind the scenes.

If you are using different aspx.cs files that define classes of the same name you can use

<compilation targetFramework="4.5" />

under <system.web> in your web.config file.

Although I would still strongly advise that you would change the class name.

I had a similar problem (Universal project, Visual Studio 2015), I solved it with the following changes:

In App.xml.cs was (it was ok):

namespace Test.Main {

Wrong, old version of App.xml:

x:Class="Test.Main"

Good, new version of App.xml:

x:Class="Test.Main.App"

This is not the best solve, but if you really don't care it is an easy solution. I simply renamed my class. So I had class Card and I changed it to MyCard.

I think this issue is because you have added for a single table, 2 DAL classes. If this table is included in a relation, then remove the table_name.dbml for it, and keep that for the related tables. You must use one of them.

I had this issue, but mine was slightly different to the issues mentioned here. I was cleaning up my project and moving around some classes into new folders. I had a 'AddFilter' class that I moved into an 'AddFilter' folder - so I had actually wound up with a class that was sharing the name of a namespace. This was a bit tricky to spot at first because I couldn't find any other classes that it was conflicting with; it was conflicting with the namespace instead.

If you copy&paste your pages don't forget to rename class names. Otherwise you get this error also with "Type already defines a member called 'OnGet' with the same parameter types"

look this happend to me when I created new file inside a folder with the same name of class in the project { folder name : Folder } and there is class name { Folder } so the namespace was the namespace.Folder so that the compiler assume that the cass defined in two places

in new file :

namespace APP.Folder
{
    partial class NewFile
    {
       // ....
    }
}

---

in the other file (the file that hase the problem):

    namespace APP
{
    partial class Folder
    {
      // ....
    }
}

-- so you can edit the folder name or remove the .Folder from the namespace at the new file

I know this is an older post, but I thought it might help someone else if I shared my experience with this error. For me, I was working in Visual Studio 2019 and using Xamarin Forms. I received this error message when I created a new folder and named it the same as a Content Page I had made previously. Apparently we're not supposed to do that...

Anyways, I had to rename the folder then go through to each individual Content Page within the folder are change their namespace (in their .cs file) as well as the x:Class within their ContentPage tag (in their .xaml file) to reflect the folder's new name.

That's what worked for me. I hope it is helpful to someone else in the future should the error rise again.

This happened to me, I noticed that there was actually another class with that same name under the same namespace "OtpService.Models.Request", so all I did was to just change the namespace of the 2nd class to "OtpService.Models.Request.ExtraObj". I did this because I did not want to change the name of the conflicting class to anything else.

I came across this partial class problem in a winform of a solution after converting from .net 4.5.1 to 4.7.2.

Initially the problem the compiler was not complaining about partial class but the use of properties.default...without qualification. After adding Global::solnNameSpace. qualifiers, then I got the partial class problem.

after viewing answers in this thread, I look at the resource designer file, I found it was generated with explicit solnNameSpace while the classes in the solution did not. Also the solnNameSpace is the same as the name of the problematic class name.

To fix the problem with the least effort and time I backed out Global... qualifier and removed the explicit namespace ... and end statements from the resource designer file. I know I may get in trouble later on if there were changes that cause auto generation of the resource designer file but I was was under tight deadline. I made documentation on the temp change instead of a better long term solution since the solution is under no change allowed for nature of the solution and multi project use.

I had this problem. It was due to me renaming a folder in the App_Code directory and releasing to my iis site folder. The original named folder was still present in my target directory - hence duplicate - (I don't do a full delete of target before copying) Anyway removing the old folder fixed this.

when you have tried everything else and still get the same trouble, there is a way out; however it will be tedious and need careful preparation.

Start another new project using existing files, or edit the project .csproj file if you are proficient in editing csproj (need backup). I will list steps for new project.

1. preparation:
   • note all references and their sources
   • note all included files from another project
2. rename the orginal projectname.csproj file
3. close solution/project
4. start new project using existing files(you will get errors from references)
5. add back the noted references
6. include/add existing file from other project(s)

if you have 2 versions of any of your code file (*.cs, *.vb etc.) inside your "app_code" folder then you will get this error because dot net would include both the files in your project and will get 2 different implementations of the same class (because of same name in 2 versions of same code file in app_code folder)

This happened to me because I imported 2 third-party libraries for RPG Ability System and both of them had an enum called ActionType.

Solved this issue by:

1. Adding namespace surrounding at least one of the class/enum which has the same name. (In my case ActionType) (This might cause a couple of other errors because some of your other files can no longer access to that class/enum)
2. Go to each line who want to reach to the class/enum, and re-adjust usages by using the required namespace at the top of the class. (click to the not found field, import the right class)(You can have 2 choices) (Shortcut is option+enter)

Note: You don't always have to come up with a new namespace name, sometimes your project has different namespaces and it's best if you put your class/enum to that namespace. (Someone apparently forgot to add that class/enum inside that namespace in my case, so I used existing one.)

namespace THMSV.RPGBuilder.Managers{

    [RequireComponent(typeof(CombatNode))]
    public class ObjectActionTrigger : MonoBehaviour
    {
        public enum ActionType
        {
            ability,
            effect
        }
    }
}

This error happened to me when I was using Visual Studio Code. I think it must have been because I was trying to build a project while there was an executable running in the same bin\debug folder. I stopped the executable, closed the folder, reopened, rebuilt, and the error went away.