I'm getting this problem building a WPF project
The name does not exist in the namespace
Everything I’ve looked at says you should
Change the namespace and the project name, build, change them back
Change the build from 86 to 64, build, and back Tried removing the
reference and letting ReSharper re-instate the reference Tried
excluding the file, build, then include the file again
None of the above worked.
I have checked that each referenced class has only one instance of it throughout the whole solution – ruling out named duplicates
The references in question are all references within the one DLL – all namespaces within this dll so it’s not like there is a cross dll issue of any sort.
Your thoughts or suggestions at this point are appreciated.
I to assume that You have this error in XAML file.
I thing it is very common problem with WPF and Visual Studio 2015.For example I have this error when I use DevExpress dlls
My suggestions is to try this:
Restart Visual Studio - it is weird but frequently it works. I don't now way it works.
Use F5 and run the program instead of build them (F6). Sometimes when You compile app the error disappear and app runs. It is also weird, but in my case it works
This not resolve the problem but it helps exclude the problem with IDE
I know the error message is common and there are plenty of questions on SO about this error, but no solutions have helped me so far, so I decided to ask the question. Difference to most of similar questions is me using App_Code directory.
Error message:
CS0012: The type 'Project.Rights.OperationsProvider' is defined in an
assembly that is not referenced. You must add a reference to assembly
'Project.Rights, version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
Source File:
c:\inetpub\wwwroot\Test\Website\App_Code\Company\Project\BusinessLogic\Manager.cs
Following suggestions here and here, I have deleted all instances of Project.Rights.dll inside C:\Windows\Microsoft.NET/*.*
According to this, I checked if .cs files in question have build action set to "Compile". They do.
I have also double checked that the .cs file containing the "Project.Rights.OperationsProvider" type is deployed to App_Code directory.
For some reason, application is not looking for the type in the App_Code directory. Since I've deleted all instances of Project.Rights.dll (that I know of), I don't know which assembly the error message is mentioning.
When you get this error it isn't always obvious what is going on, but as the error says - you are missing a reference. Take the following line of code as an example:
MyObjectType a = new MyObjectType("parameter");
It looks simple enough and you probably have referenced "MyObjectType" correctly. But lets say one of the overloads for the "MyObjectType" constructor takes a type that you don't have referenced. For example there is an overload defined as:
public MyObjectType(TypeFromOtherAssembly parameter) {
// ... normal constructor code ...
}
That is at least one case where you will get this error. So, look for this type of pattern where you have referenced the type but not all the types of the properties or method parameters that are possible for functions being called on that type.
Hopefully this at least gets you going in the right direction!
Check target framework in the projects.
In my case "You must add a reference to assembly" actually meant, that caller and reference projects didn't have the same target framework. The caller project had .Net 4.5 , but referenced library had target 4.6.1.
I am sure, that MS compiler can be smarter and log more meaningful error message. I've added a suggestion to https://github.com/dotnet/roslyn/issues/14756
In my case this was because doing a NuGet package update had only updated references to a dll dependency in some but not all projects in my solution - resulting in conflicting versions. Using a grep-style tool to search text within *.csproj files in my solution it was then easy to see the projects that still needed to be updated.
When you get this error, it means that code you are using makes a reference to a type that is in an assembly, but the assembly is not part of your project so it can't use it.
Deleting Project.Rights.dll is the opposite of what you want. You need to make sure your project can reference the assembly. So it must either be placed in the Global Assembly Cache or your web application's ~/Bin directory.
Edit-If you don't want to use the assembly, then deleting it is not the proper solution either. Instead, you must remove all references to it in your code. Since the assembly isn't directly needed by code you've written, but instead by something else you're referencing, you'll have to replace that referenced assembly with something that doesn't have Project.Rights.dll as a dependency.
In my case, I was referencing a library that was being built to the wrong Platform/Configuration (I had just created the referenced library).
Furthermore, I was unable to fix the problem in Visual Studio Configuration Manager -- unable to switch and create new Platforms and Configurations for this library. I fixed it by correcting the entries in the ProjectConfigurationPlatforms section of the .sln file for that project. All its permutations were set to Debug|Any CPU (I'm not sure how I did that). I overwrote the entries for the broken project with the ones for a working project and changed the GUID for each entry.
Entries for functioning project
{9E93345C-7A51-4E9A-ACB0-DAAB8F1A1267}.Release|x64.ActiveCfg = Release|x64
{9E93345C-7A51-4E9A-ACB0-DAAB8F1A1267}.Release|x64.Build.0 = Release|x64
Entries for corrupted project
{94562215-903C-47F3-BF64-8B90EF43FD27}.Release|x64.ActiveCfg = Debug|Any CPU
{94562215-903C-47F3-BF64-8B90EF43FD27}.Release|x64.Build.0 = Debug|Any CPU
Corrupted entries now fixed
{94562215-903C-47F3-BF64-8B90EF43FD27}.Release|x64.ActiveCfg = Release|x64
{94562215-903C-47F3-BF64-8B90EF43FD27}.Release|x64.Build.0 = Release|x64
I hope this helps someone.
It just happened to me that different projects were referencing different copies of the same dll.
I made sure all referenced the same file on disk, and the error disappeared as I expected.
Unloading and reloading the class library in Visual Studio solved this for me.
For me, this was caused by the project both directly and indirectly (through another dependency) referencing two different builds of Bouncy Castle that had different assembly names. One of the Bouncy Castle builds was the NuGet package, the other one was a debug build of the source downloaded from GitHub. Both were nominally version 1.8.1, but the project settings of the GitHub code set the assembly name to BouncyCastle whereas the NuGet package had the assembly name BouncyCastle.Crypto. Changing the project settings, thus aligning the assembly names, fixed the problem.
It didn't work for me when I've tried to add the reference from the .NET Assemblies tab.
It worked, though, when I've added the reference with BROWSE to C:\Windows\Microsoft.NET\Framework\v4.0.30319
I had this issue on a newly created solution that used existing projects. For some reason, one project could not "see" one other project, even though it had the same reference as every other project, and the referenced project was also building. I suspect that it was failing to detect something having to do with multiple target frameworks, because it was building in one framework but not the other.
Cleaning and rebuilding didn't work, and restarting VS didn't work.
What ended up working was opening a "Developer Command Prompt for VS 2019" and then issuing a msbuild MySolution.sln command. This completed successfully, and afterwards VS started building successfully also.
one of main reason can be the property of DLL
you must before do any thing to check the specific version property if it true make it false
Reason:
maybe the source code joined with other (old)version when you build it , but this Library upgraded with new update the version now different in the Assembly Cash and your application forbidden to get new DLL ,and after disable specific version property your applacaten will be free to get the new version of DLL references
Maybe a library (DLL file) you are using requires another library. In my case, I referenced a library that contained a database entity model - but I forgot to reference the entity framework library.
This can also mean you use a library, which exposes (public) types that are defined in a library. Even when you do not use these specifically in your library (the one that doesn't build).
What this probably prevents is you writing code that uses a class (which in its signature has the types from a library not referenced) that you cannot use.
For me the reason why the error appeared was that the WebForm where the error was reported has been moved from another folder, but the name of its codefile class remained unchanged and didn't correspond to the actual path.
Initial state:
Original file path: /Folder1/Subfolder1/MyWebForm.aspx.cs
Original codefile class name: Folder1_Subfolder1_MyWebForm
After the file was moved:
File path: /Folder1/MyWebForm.aspx.cs
Codefile class name (unchanged, with the error shown): Folder1_Subfolder1_MyWebForm
The solution:
Rename your codefile class Folder1_Subfolder1_MyWebForm
to one corresponding with the new path: Folder1_MyWebForm
All at once - problem solved, no errors reporting..
The type 'Domain.tblUser' is defined in an assembly that is not
referenced. You must add a reference to assembly 'Domain,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
**Solved:**
Add reference of my domain library layer to my web app libary layer
Note: Make sure your references are correct according to you DI container
In my case this was because I used
Implicit Operator
between BLL and DAL classes.when I want to use BLL Layer In Application Layer I got this error.
I changed
implicit operator
to
explicit operator
it be OK.
Thanks
In my case the version of the dll referenced was actually newer than the one that I had before.
I just needed to roll back to the previous release and that fixed it.
I have a similar problem, and I remove the RuntimeFrameworkVersion, and the problem was fixed.
Try to remove 1.1.1 or
My problem was that the Output Type for one of my projects was set to Console Application. To fix this, I right-clicked the project, chose Properties, clicked the Application tab, and change Output Type (from Console Application) to Class Library. After I re-compiled, this error went away.
Clean your solution and rebuild worked for me (in Visual Studio, these are options you get when you right click in your solution explorer), the error is gone in my project.
A project that I've been working on for a long time without any problems suddenly started throwing errors such as
The type or namespace name 'xxx' does not exist in the namespace 'yyy' (are you missing an assembly reference)?
In this case, the namespaces were all core .Net libraries such as System.Data, Linq, and IO that I've been using without any problems.
I've worked through all of the issues in this question such as making sure all the projects in the workspace are using the same version of .Net for the Target Framework setting.
I removed all the libraries in question and re-added them but the problem persisted. I doubt they libraries themselves are corrupted as I reference them in other projects within the solution.
After rolling back through my work with TFS I managed to work out what I'd done that had created this error: I'd added a folder called "System" to my project and put a class file in it.
This is an easy issue to reproduce: create a project, add a folder called system to it (it will still compile at this point) and then create a .cs file in it, that's when all the fun errors will occur.
The problem stems from the name of the "System" folder which leads to any files created in it being under the namespace ".System".
I can understand why having a folder / namespace called "System" would cause problems now but I think it would help if Visual Studio warned when creating a folder / namespace of such a name to stop this problem happening in the first place. I've logged a bug with MS, at least having this logged might help any other people who have made the same mistake as me!
I had the same issue after my system shut down unexpectedly and even though VS tried to restore, the problem popped up.
I had two projects in my Solution Explorer. To solve this, I right-clicked the project that was associated with the error message and selected 'Build'.
After that, the issue was resolved.
Just to add that the problem was permanently solved after I added a reference to the 'project' from the other 'project'.
I renamed the namespace of the file I was referencing from myproject.shared.constants to myproject.SOMETHING.shared.constants
After that It suggested "use myproject.SOMETHING.shared.constants" as suggestion. I renamed it back to myproject.shared.constants and then it worked.
Try to Clean and Then Rebuild the dll file .I was experiencing the same problem tried different suggestions from internet but none of them work.But it will. In case you don't know how follow these steps:
open your dll project file.
2.click on solution Explorer Right click on Your Dll Project Name you will find Clean and Rebuild Option.
I've recently completed a (hopefully successful) VB to C# conversion on a decent-sized library. However, I am receiving some trouble from the compiler when trying to build it. I created a small helper library called ExtensionMethods, compiled it, dropped the .dll in the bin folder of the outlying project, and added a reference to it in the newly-converted library. The library has two namespaces, ExtensionMethods.Json and ExtensionMethods.Enums. In any class where I want to use the Enums namespace, I import it with using ExtensionMethods.Enums. I do the same for the .Json namespace (which works fine, by the way).
The following is picture evidence of what is happening:
Notice the blue squiggle under Enums with a simultaneous suggestion for Enums from Intellisense. Here is proof that VS actually recognizes the assembly (.ToInt() is the name of the extension method):
Notice how .ToInt() is both suggested by Intellisense as an extension method AND does not have a squiggle under it, even though ALLEGEDLY...
(three files use this namespace)
which would make sense, except for...
Essentially, what this is saying is that, "Yes, Jason, you have referenced all your assemblies correctly, yes, your assemblies contain the namespaces they should, but no, I don't feel like compiling today."
I just want to compile and be done with this monster. What am I missing here?
UPDATE
ExtensionMethods.Json, another namespace in ExtensionMethods works fine when referenced and does not produce an assembly reference error. Both projects were created on the same 64-Bit machine and everything targets .NET 4.
So here's how I fixed it. Basically I went and deleted .DLL from my bin folder, deleted every reference to it, dropped the .DLL back in, and re-referenced everything. Now, for some strange reason, that compilation problem is gone. Yay.
I vaguely remember something like this when I was struggling with a 64 vs 32 bit problem. Make sure the reference is usable by your project's platform. If I'm remembering correctly, I was referencing a 32-bit DLL in a project that was compiled for "Any CPU" on a 64-bit platform, or something of the sort, this was a while ago.
Only way to solve this I found when I had the same problem was commenting out all that and related code, removing the references, re-build all, adding the reference again and uncommenting the code, re-build.
note: re-build, not build... and just re-adding the reference doesn't help
It seems the builder gets an invalid partial build or something (don't know how it technically works) that it won't overwrite even if you tell it to re-build. You need to get rid of all the code and references and re-build to get rid of the invalid state.
(yes I know, it's a lot of work and it sucks, but it's the only way I found to get rid of it)
I have a WPF/ASP.NET project which I haven't worked on for a while (ResourceBlender.NET - http://resourceblender.codeplex.com/). The project contains a DataLayer and a Core layer, these are both used by the WPF application and ASP.NET project in the solution.
If the WPF project is set as the startup project and I try to build the application, I get "The type or namespace name 'whatever' could not be found (are you missing a using directive or an assembly reference?)".
The error list shows these when I try to build, run or debug, but double clicking and going to the error shows no actual errors in the editor and everything is highlighted as normal.
The ASP.NET project builds fine. I'm absolutely clueless on this one, as there are no obvious errors to fix - could it be metadata somewhere?
Check that all assemblies does not target the 3.5/4.0 Client Profile (It is probably the WPF application that is the culprit). This will cause exactly the error message you're describing.
This type of thing is really hard to debug without being able to see your solution setup, but here are the things I would try:
Expand the references in your WPF project, make sure they are all resolving
Double-check that none of your references have "specific version" set to True and point to an old/nonexistent version
Do a "Clean" on your solution, close VS and delete your bin and obj directories, etc. to clear out potentially old copies of dlls that may be messing up your build
Good luck!
Try the following:
Right-Click on the solution on do a "Clean Solution"
Try to build each project separately
Check the references on your projects for missing assembly references
Compile issues like this can be overwhelming. It's usually best to troubleshoot one project at a time as suggested in these tips:
5 Debugging Tips for a Solution That Won't Compile
Actually read the Output window text.
often errors or warnings that are pertinent appear in there but aren't obvious when following the Error List window links.