I added a reference to a different solution assembly to my project.
I also added a using directive
using MyAssembly;
MyAssembly only exposes one type MyClass.
However when I want to reference it in code I still have to write full name:
MyAssembly.MyClass
Isn't the using statement suppose to solve that? The reason is, I'm getting expections that the MyClass type cannot be found.
Seems like you're having same class myClass on both solutions. Hence, you will need to explicitly provide the assembly name in order to let the compiler know which class of both you are referring to.
Its also possible when you reference higher .Net framework version build dll to lower .Net framework Projects. This is very common issue. But agreed that you face the same issue when you have same class defined in two dlls.
Related
I have a CustomerOrderContext class in CustomerOrder.Data project in my solution. In another project, CustomerOrder.App, I have CustomerVM class. In this class I'm creating a CustomerOrderContext instance. But I get this following error:
Error 2 The type or namespace name 'CustomerOrderContext' could not
be found (are you missing a using directive or an assembly
reference?)
I have changed Build Actions of both projects to Page and then back to None and I have started to get this error. I have this line in CustomerVM:
using CustomerOrder.Data;
so I guess I shouldn't get this error. CustomerOrder.Data is also in References list of CustomerOrder.App. Can you tell me how I can fix this problem?
Thanks.
The issue is solved when I created new project, copied & pasted all classes.
be sure that CurstomerOrderContext class is marked as Public and not Internal.
Can you check if the framework versions are compatible? See https://stackoverflow.com/a/4286625/2478357.
Also, if you use Entity Framework (and CustomerOrder.Data uses EF), check if your CustomerOrder.App has a reference to the Entity framework dll. (This also applies to other imported dll's..)
you need to add Reference of that project (.dll) in your project.
You will find it when you right click your solution and add the (.dll) of other project in debug folder.
To access the class you must have same namespace
and
Check that both projects follow the same .Net Framework
I have added Class Library in my web Project through Add reference option, but i am facing an error
Error 2 The type or namespace name 'UserDetailsDll' could not be
found (are you missing a using directive or an assembly reference?)*
I hope some one will help me.
Thanks in Advance.
There are a few possibilities as to why that is happening:
You're missing a using statement. Try using the whole name of the class (namespace, then class name) you're trying to use.
Your DLL is targeting a different processor architecture. Check the properties of your web application and your DLL and see if they are both targeting the same CPU.
Your DLL is for a different .NET framework than your web application. Check the target framework in the project properties.
Finally, check the references in Visual Studio for a little yellow warning icon next to your referenced DLL. It's presence indicates that the DLL couldn't be found / referenced in the first place.
You need to either add a using in your code file or specify the full name to the class you want to use.
Both solutions can be autogenerated. Rightclick on the class that won't get resolved and click on Resolve -> using XXXX
I have a class library I've built for a coworker to use that, after giving her the .dll file, I cannot get to work. The name of the .dll file is "BatchDashboard." The name of the namespace is "BatchDashboard," and the name of the class (there is only one) is "BatchDashboard." Is it a problem to have all three similarly named? Visual Studio is able to add the reference just fine. However, this statement:
using BatchDashboard;
spits out the following error:
The type or namespace name 'BatchDashboard' could not be found (are you missing a using directive or an assembly reference?
Likewise, I cannot instantiate a new 'BatchDashboard' object.
Could someone tell me what I am doing wrong?
Thx!
EDIT
I have tried adding the reference to another test project on my computer and receive the same results.
SECOND EDIT
Changing the access modifier to public for the "BatchDashboard" class fixed the issue with the using statement. However, when I try to instantiate an object like so:
BatchDashboard batch = new BatchDashboard();
I got the following error:
'BatchDashboard' is a namespace but is used like a 'type'
It was necessary for me to have different class and namespace names to work. Thank you!
I think, I know what problem you have. When you created your class file, you probably didn't change access to your class to "public". In .Net, unless you have public members in the assembly, the namespace wouldn't be found in "using" directive.
Basically, check if the class you have is a "public class"
Here are my best guesses:
You compiled it against the wrong CPU target
You have a dependency on a Runtime library that should be added as a reference to the
project also.
Make sure that:
The library is added as reference to the project
That library is in a equal or prior .NET version compared to your project's .NET version.
(Yet another question from my "Clearly I'm the only idiot out here" series.)
When I need to use a class from the .NET Framework, I dutifully look up the documentation to determine the corresponding namespace and then add a "using" directive to my source code:
using System.Text.RegularExpressions;
Usually I'm good to go at this point, but sometimes Intellisense doesn't recognize the new class and the project won't build. A quick check in the Object Browser confirms that I have the right namespace. Frustration ensues.
Using HttpUtility.UrlEncode() involved adding the appropriate directive:
using System.Web;
But it also required adding a reference to .NET Framework Component for System.Web, i.e. right-click the project in Solution Explorer, select Add Reference and add System.Web from the .NET tab.
How might I discern from the documentation whether a .NET namespace is implemented by a .NET Framework Component that must be referenced? I'd rather not hunt through the available components every time I use a namespace on the off chance that a reference is needed.
(For those who like to stay after class and clean the erasers: Will Organize Usings > Remove and Sort also remove references to componenents that are not used elsewhere in the project? How do you clean up unnecessary references?)
Check out this link for UrlEncode:
Namespace: System.Web
Assembly: System.Web (in System.Web.dll)
The Assembly line tells you which dll to reference.
You'll note that the documentation (e.g. http://msdn.microsoft.com/en-us/library/system.web.httputility.aspx) tells you the name of the assembly/DLL that the class should be found in, along with the class's namespace.
Namespace: System.Web
Assembly: System.Web (in System.Web.dll)
On a side note, I know it can be a little dear, but Resharper makes things like this so much easier. If you're a serious developer, you may want to consider investing in a license. For the eraser-cleaners, Resharper adds a handy little "Find Code Dependent on Module" item to the right-click menu on references in the Solution Explorer. It's not quite an automatic cleanup, but it makes it a lot easier to see whether something's still being used by your project.
The documentation specifies two things for any type:
The namespace of the type (for the using directive)
The assembly containing the type (this is what you add a reference to)
To take an example where the two are different, look at the documentation for Enumerable:
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
If you look at the MSDN docs, e.g.
http://msdn.microsoft.com/en-us/library/system.web.httputility.aspx
It tells you the namespace and the assembly that is required.
First, a correction to your terminology: What you are referencing is called an "assembly". An assembly contains classes that belong to a namespace. A namespace can span across multiple assemblies.
Most assemblies are named the same as the main namespace that is contained in them. For example, System.Web exists in System.Web.dll. The documentation also usually tells you which assembly needs to be referenced.
I think that you are running into a difference between c# and C here. To compare: In C, all you need to do to include a new library is to include it in the header.
It .net, you need to be aware of 2 things:
A namespace can span more than one assembly/dll (that means that you might not get a compiler error on the using clause, because some of the dlls that support that namespace are referenced -- just not the one that you need)
To "see" the contents of a given assembly, you have to add a reference to it. The using clause alone just gives you some short-cut syntax so that you can write HttpUtility.Encode(), instead of System.Web.HttpUtility.UrlEncode(), you have to add the reference in order for the compiler to "know" about the class.
To avoid your problem:
In the MSDN documents, pay attention to the assembly that the class is in, and make sure that you have a reference to the assembly.
If you browse to the MSDN for the class you're trying to use. It typically tells you the assembly that the class is in. For example the Regex class is in Assembly System (in System.dll) or the HttpUtility class is in Assembly System.Web (in System.Web.dll).
I believe tools such as ReSharper help with this, as well, and automatically references the assemblies you need.
I'm pretty sure you have to manually remove the unused references in C# projects. In VB.NET projects there's a button to list the unused references when you're in the project properties page. I don't see this in C# projects, though.
The full error is as follows:
The type
'System.Windows.Forms.Control' is
defined in an assembly that is not
referenced. You must add a reference
to assembly 'System.Windows.Forms,
Version=2.0.0.0, Culture=neutral,
PublicKeyToken=b77a5c561934e089'.
and it points at the very first statement (an Debug.Assert line) in the very first class in a library project that doesn't need System.Windows.Forms (or so I thought). I know how to solve it: add the mentioned reference. But how do I find out what library is causing this error, or better, what part of the code triggers using the WinForms library?
Normally, you can add libraries that reference others, but you only need to add references to these others when they're actually used.
EDIT: Alternative solution
This or similar problems can also be resolved using the Binding Log Viewer Fuslogvw.exe from Microsoft's Framework Tools. It shows all attempts and successes of assemblies your application binds to.
I suspect there's no line of your code that's causing this, since you say you aren't making use of the System.Windows.Forms types and the compiler error isn't pointing to a (useful) line of your code.
What I think is happening is that you're referencing a library which has a publicly-visible method or property that either returns a System.Windows.Forms.Control or takes one as a parameter. It doesn't matter whether you actually end up calling that method/property, the fact that it's publically visible means that your own code has to be able to resolve all the types that the library is using. If the library only used System.Windows.Forms internally, you wouldn't be experiencing this.
It also means just looking at the dependencies of the assemblies you're depending on may merely narrow down the list of suspects, since there could be some assemblies that depend on System.Windows.Forms internally (no problem) and the one troublemaking assembly that has a public parameter / return value of a type from the S.W.Forms assembly.
My suggestion is you just set up an empty project without a reference to S.W.Forms, then add each of your dependencies in turn and try to compile after each one.
I had the same error.
The problem was that I used a reference to a project, which uses System.Windows.Forms inside.
The solution is to add a reference to System.Windows.Forms also in your project.
Use something like NDepend or Reflector or the Object Browser to check the dependencies of the assemblies you depend on.
I cannot think of any other way given the info above.