In one namespace (Ventosa.Graphics) I have a public class named Model
namespace Ventosa.Graphics
{
public class Model : GraphicsResource
{
public Model(...)
{
...
}
...
}
}
Then in another project I try to access this class
Model player = new Model(...);
But this line creates an error. C# recognizes that Model exists, but claims that it isn't accessible due to it's protection level. Shouldn't making it public mean it's accessible from everywhere?
And yes, the base class GraphicsResource is public.
This happens in a few other places in my project too, all with classes that are derived.
EDIT:
The exact error message is (in German):
Der Zugriff auf "Ventosa.Graphics.Model" ist aufgrund der Sicherheitsebene nicht möglich. Translated to English, it says: "Ventosa.Graphics.Model" is inaccessible due to its protection level.
You describe something that clearly should not be. I'd suggest that you try to reproduce the problem in the simplest way possible. You probably won't be able to. Then add to your sample, making it more and more like your production code, until you trigger the problem.
Remove the reference to the superclass GraphicResource. Make sure there's only one constructor defined. Try to instantiate that class from the same namespace, using full namespace references (not using statements) and that single, explicit constructor. It'll probably work.
If it doesn't work, step back a bit and define a new type entirely (Ventosa.Graphics.ModelTest or something). Make sure that works.
Now, add pieces back in. Inherit from GraphicResource, try that. Remove the namespace qualifications; use using instead. Move the instantiation to a different namespace, then a different assembly.
You've verified that the definition of the GraphicResource class is public. What about any of its superclasses?
I know this may sound silly, but have tried to restart Visual Studio (after Cleaning and Rebuilding the solution)? I noticed some strange behavior, especially if you have Code-Coverage enabled and some of the Powertools for Visual Studio installed.
Was Model internal in some previous builds? It's a really common name.
Edit: A way to make sure you actually have the right type, you can hover the "Model" declaration in your second project and press F12 (or right click and choose "Go To Definition", don't know the german term right now). This should take you to your class or to the definition of some other "Model"-class (.NET internal types are displayed too).
Related
I'm new to .Net and I just saw this code that doesn't make sense to me (slightly abridged):
namespace test
{
public class sub : super
{
public sub(string text);
}
}
As you can see, there is a constructor that takes an argument, but does not implement a definition. How does that work? My guess is that it somehow relates to the super class, but I dont understand how, and I havent been able to find anything on Google.
Edit: Im running this in VS2010, and I just noticed that the tab has [from metadata] in the title. Perhaps this is why?
That's not code.
That's text that looks somewhat like code based on the metadata in the assembly. You'll see this when the IDE doesn't have access to the source code in question (For example, you press F12 on a method in a referenced assembly.) It provides the method signatures, properties, fields, etc from the types, without providing any of the actual implementation.
As written, the code you posted wouldn't even compile in C#.
If from the metadata, it's not going to show you the implementation of the methods.
It looks like code but it is text based on the metadata in the assembly. It means that the IDE is unable to access the source code in question.
I can't figure out this error in visual c#.
Error 1
'Engine.VerticalMenu' does not contain a definition for '_buttons' and no extension method '_buttons' accepting a first argument of type 'Engine.VerticalMenu' could be found
(are you missing a using directive or an assembly reference?)
For this line:
System.Diagnostics.Debug.Assert(false, _menu._buttons.Count.ToString());
I have two projects, first one is Engine with same namespace Engine and of type class library, and the other one is windows form app that uses this Engine library. I have both using directives and references to project, what could possibly be causing this? Thank you.
Looks like _buttons is private class member, so you can't access it from the outside.
Either make it public, or even better add public getter to the class of _menu:
public TypeOfButtonCollectionHere Buttons { get { return _buttons; } }
And change the calling code to:
System.Diagnostics.Debug.Assert(false, _menu.Buttons.Count.ToString());
Is _buttons possibly private? Then it is not visible outside of the menu class and you can't access it. Wrap it to a public property and you can access it.
It sounds like a naming conflict (namespace or class). Have you tried using the fully qualified name for the class? Without more information this is just a shot in the dark.
No, its not the public thing, vs has other errormessages for that. It looks like _menu doesn't have a member _buttons at all. So this means either the class or the interface _menu is of doesnt have _buttons.
Check that all the assemblies referenced by the project Engine is also referenced by your Win form.
It would usually give another error if that's the case but not always.
If they are all referenced. Try a rebuild of just the Engine project. VS might throw the mentioned error if there's a compilation error in a referenced project. Those errors should show up in the error log, so you could also check the error log to see if there are other errors some of which is in engine.
(Even if that's not the case I would personally still build Engine alone, to completely rule it out)
I got a strange error when tried to build my project ExpertSystem in solution ExpertSystem:
Error 1 The type name 'App' does not
exist in the type
'ExpertSystem.ExpertSystem' D:\Users\Kirill\Documents\Visual
Studio
2010\Projects\ExpertSystem\ExpertSystem\obj\x86\Debug\App.g.cs 60 26 ExpertSystem
I didn't even knew that VS creates this file while building. So, I started search the problem in my last edits in code and found that problem is in my last class:
namespace ExpertSystem
{
public class ExpertSystem
{
//...
}
}
When name of class is changed to something different from ExpertSystem, project compiles without errors.
Can anyone explain, can I actually have classes in C# with the same name as namespace/project/solution? Or is this a some kind of VS/WPF bug?
Thanks.
VS generates partial class for each XAML file (not during build, but during design), in order (for instance) to declare and fill the named components as class fields.
If you want to easily read the content of the designer generated App.g.css file (associated with the App.xaml and App.xaml.cs file), go to the App.xaml.cs file and perform a "Go to Definition" on the InitializeComponent() function call in the class constructor. I don't know what lurks in your, but I would expect that the designer generated something like this (maybe not this, but the issue will be the same):
var foo = (SystemExpert.App)(Application.Current)
Which should be understood as:
var foo = (global::SystemExpert.App)(Application.Current)
Now, if you create a SystemExpert class in your SystemExpert assembly namespace, and as the App class is declared in the SystemExpert namespace too, the compiler will understand that:
var foo = (global::SystemExpert.SystemExpert.App)(Application.Current)
^^^^^^^^^^^^^^^^
the current namespace
Naming a class exactly the same way as a namespace is bad practice: it can confuse the compiler.
Can anyone explain, can I actually have classes in C# with the same name as namespace/project/solution?
Yes, you can. It's part of the C# language.
Therefore the compiler can't figure out whether the code meant to look for the ExpertSystem.ExpertSystem namespace or the ExpertSystem class in the ExpertSystem namespace. (Well it can, but it got it wrong.)
To complement BoltClock's answer with a solution that will work while keeping the namespace and class names as they are:
The error is reported in a file named App.g.cs, which is generated by the compiler. Thus, fixing the issue in that file will not help, as the file will be overwritten with the error upon the next compilation (or rewritten once you have copied the code to another machine).
However, you can change the App.xaml file, from which App.g.cs is generated. The root element of the file will start with something like
<Application x:Class="ExpertSystem.App"
In there, the namespace ExpertSystem is supposed to be found, but with the class having the same name, the compiler assumes that App is a member or a nested type in your class ExpertSystem.ExpertSystem.
By pondering about this, you will realize that the compiler first tries to evaluate the value of the x:Class attribute relatively to the ExpertSystem namespace for some reason. This behaviour is responsible for your problem, but as we now know the specifics of the behaviour, we can write the code accordingly - with an identifier that is qualified relatively to the namespace ExpertSystem:
<Application x:Class="App"
After this change, it should compile fine, even if both the namespace and the class are named ExpertSystem.
I have a base class, defined as below (I'm also using DevExpress components):
public abstract partial class BaseFormClass<R> : XtraForm where R : DataRow
{
...
}
Contrary to what I've read from elsewhere, I'm still able to design this class. I didn't have to create a concrete class from it to do so. But, when I create a concrete class descended from it (as below), that class won't work in the designer.
public partial class ConcreteFormClass : BaseFormClass<StronglyTypedRow>
{
...
}
I get this message:
The designer could not be shown for
this file because none of the classes
within it can be designed. The
designer inspected the following
classes in the file:
ConcreteFormClass --- The base
class
'BaseFormClass'
could not be loaded. Ensure the
assembly has been referenced and that
all projects have been built.
Has anyone seen this before? Any sort of known workaround?
Sorry, but this just isn't going to work (which is a shame -- I've wished in the past that you could do this, too.) The problem is the basic methodology of the designer.
To present you with a model of your form, it doesn't actually try to construct the form itself; if it did that, you'd run into other problems -- what if your form doesn't have a parameterless constructor? Instead, it actually instantiates an instance of the base class of your form. Then it sweeps through your InitializeComponents() method and "layers on" all the controls that you've defined there onto the base form.
So it's obvious why this won't work. You can design an instance of BaseFormClass, because to design that, it creates an instance of XtraForm, which is concrete. But you can't design an instance of ConcreteFormClass, because to do so, it would need to create an instance of BaseFormClass, which is abstract.
The easiest workaround for this is to just make BaseFormClass non-abstract. (If you want to make absolutely sure nobody can create one, perhaps you could make the default constructor private? I'm not sure if the designer can handle that, but I don't see why it couldn't.) Sucks, but such is life. Complain to Microsoft and maybe it'll be better in Visual Studio 2012.
This sounds like a really similar issue to getting the designer to render forms that have an abstract base class. I haven't done any generic multi inheritance but you could at least try my approach and see if it works.
Edit: Yep, ok, just tried it, my solution works for sure. You just have to modify the middle classes definition and the forms definition (wrapped in the #if DEBUG)
Let me know if you're able to try it!
I'm having a problem with conflicting namespaces and code that gets autogenerated by the forms designer in Visual Studio 2008. I have search many forums and different documentation, but have not been able to find any solution to this problem.
I have one assembly called Foo.dll with the following namespace/code:
namespace Foobar.System
{
public class MySystemClass() { }
}
Then, I have another assembly which contains som commonly used forms:
namespace Foobar.MyCommonForms
{
public class MyForm : System.Windows.Forms.Form
{
public void SomeMethod()
{
var systemclass = new Foobar.System.MySystemClass();
}
}
}
Here, the compilers display the following error: Type or namespace 'Windows' is not part of namespace 'Foobar.System'. Obviously, the compiler tries to look for the class System.Windows.Forms.Form in namespace Foobar.System.Windows.Forms!
I have been able to solve this by using the alias 'x' instead of 'global' when referencing to the assembly Foo.dll, and declaring 'extern alias x' in my code files, and put 'x::' in front of every reference to types and classes in the namespace Foobar.System. The code compiles.
But it seems that the forms designer don't recognise this, and gives me an error when trying to display the form. This, again, can be solved by manually putting 'global::' in front of every reference to classes in System.Windows.Forms (e.g. global::System.Windows.Forms.Button), but every time chances are made to the form, the code is automaticaly re-generated, and the 'global::' part is removed.
So, the question is: Is there a way to make the forms designer aware of the alias 'x' that is used to reference my assembly Foo.dll, or is there another, better solution to this? Renaming the namespace Foobar.System to something else is just too much work.
There's no way around this, from what I can tell.
The popular refactoring tools such as Resharper or Refactor! both include the ability to globally rename a namespace. I'd seriously consider using those.