I have 2 projects, one built in VB.NET and another in C#.NET. I want to use certain functionality of VB.NET into C#.NET and hence I have added the dll file of VB.NET solution into C#.NET as a reference by browsing the dll from my system.
Say dll name for VB.NET is myData.dll
In my C#.NET project I am trying to declare it as a namespace i.e. "using myData;" and its giving me an error of "Type or namespace name could not be found"
Am I missing something??
A clue about how your VB.NET project is organized. There are some things that can go wrong and you obviously are not aware of them, so lets find out.
According to our information the dll is added as reference.
Say dll name for VB.NET is myData.dll
Ok, so that is the DLL and you reference it.
declare it as a namespace i.e. using myData;
No, you do NOT declare "it as a namespace". You tell the compiler to also look in this namespace for classes. Now, you do NOT tell to compiler whether myData.dll actually contains the namespace myData. This is a totally different thing. You can do without using - if you prefix every class. Nothing in the using statement references a dll.
It could be VB.NET has wrapped another namespace around and it is myData.myData. No joke. It could also be you forgot to make the classes public.
To find out:
Open the DLL using Object Browser ("View", "ObjectBrowser") and look what namespace and classes are in the DLL.
Go and look for the class you want to use and see what it says there. You may be surprised about the classes and / or the namespace.
Related
In Visual Studio 2022 we have the classic search function with which we can find a particular string of text in our solution. I'm wondering if there is a way to lookup all the classes inside a file that are defined in a package that is imported via the using directive.
Say for example i'm using package x.Business in my namespace using x.Business; is there a way to then lookup the classes inside this namespace which are coming from this imported package?
What I think you're asking is... "In any class file in my own solution, I want to be able to identify which types used in it (for parameters, variables, etc) are from a particular assembly that is in a using directive."
I don't know of any tool that does this, but the easiest way to identify usages in your file is to comment out the using directive. Any types, methods, etc that exist in that namespace will turn red showing that they can't be found.
(By the way, now is a good time to learn the proper term for those lines at the top of the class files. They're called "using directives", and they're not importing a whole package necessarily, but rather a particular namespace. Not to be confused with "using statements", which are a statement you can write inside of a method that automatically handles disposing of resources.)
How can I create a type in vb.net and use the type in c#?
I guess I need to compile the vb project and add reference to the dll but have no idea if this is the right way to do it, or the reference will be valid.
Doing this is not for fun, we have some vb code and we're considering this option.
Just create a Class Library project in VB, and then add a reference to that project from your C# project. (Or if it's in a different solution, add a reference to the DLL created by the VB project.) It should be absolutely fine - you'll have access to all the Public types from your class library.
To address the comment in your question, the projects can both default to the same namespace, but it's generally a better idea to make each project have its own namespace, so it's clear where any particular type comes from.
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.
I hit this weird namespace issue when adding my first 'Service Reference' to a client project in Visual Studio 2010.
If my project's default namespace uses two or more parts, e.g. MyCompany.MyApp then when adding a Service Reference a Reference.cs file is created containing the namespace MyCompany.MyApp.ServiceReferenceName with a lot of auto-gen code with fully qualified names, e.g. System.SerializableAttribute, System.Runtime.Serialization.DataContractAttribute.
The Reference.cs file will be full of compilation errors because the compiler starts treating the System namespace as sub member of the MyCompany.MyApp namespace. You get an awful lot of errors along the lines of:
The type or namespace name 'Runtime' does not exist in the namespace 'MyCompany.MyApp.System'...
If I amend the namespace at the top of the Reference.cs file to something simple, e.g. MyCompanyMyApp.ServiceRefernceName then the compiler behaves and recognises the System namespace references as decleration of .net's System namespace.
I'm using a different workaround for now as I really want to keep my multi-part namespaces. My current alternative is to append global:: in front of the System namespace references to force the complier to do the right thing. In fact, if the 'Add Service Reference' wizard uses T4 templates I may just amend those to embed my workaround at the source.
Questions
I'd really like to understand what's going on here and why a multi-part namespace causes this issue. Presumably there's more to namespaces than I thought. Secondly, would really like to work out a better solution than performing a global Find/Replace every time I add a Service Reference or mucking around with some T4 templates.
I found the answer here somewhat unclear, so I thought I would add this as an example (I would do it in the comments but it looks better here):
So I have this as my default namespace:
namespace RelatedData.Loader
But I also add a class named:
public class RelatedData
{
}
Because the class name matches a portion of the namespace when it generates your proxy with Add Service Reference it gets confused.
The answer here was to rename my class:
public class RelatedDataItem
Ahh well I found the cause eventually.
I'm working against a very large third party WCF API and ... one of their namespaces is LameCompany.System (!!) Carnage then ensues...
Arrrgghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
The lesson to learn here is when Visual Studio/.net compiler stops recognising the BCL's System namespace you have a namespace/type in your project called System. Find it, remove it, shoot the developer that created it.
I found that having a class name similar to your namespace causes this.
Try renaming your class name
I ran into a similar issue with VS2012 described by jabu.hlong and Simon Needham after minor changes in the client project that has the references to the WCF services after updating the reference to the services. I got lots of errors compiling the Reference.cs files generated and so on (the generated files of the XAML as well).
I have selected to reuse types from specific assemblies in my solution and got a similar problems with the namespaces.
The error I get is that the namespace of the reused assembly and the namespace of the generated types can not be found when used in the Reference.cs. Both namespaces have in common the first parts, as they are from the same solution. My namespaces in the solution are like appname.tier.technology.project. Both conflicting namespaces are Appname.Dto.Modulename (the reused assembly) and Appname.Client.Wpf.ServiceName (the namespace in the client project using the services for the generated types).
The problem arises after a minor change in the client project, when I created a new utility class in the namespace Appname.Client.Wpf.Appname. I choose that namespace because the Appname is also the name of a module in the client project. This seems to confuse the compiler and can not resolve both namespaces in the generated Reference.cs. After changing the namespace of the utility class to avoid using two identical parts in it and updating the service reference, the compiler errors in Reference.cs dissapears.
I tried different things (and tried different namespaces when adding the service reference), but nothing worked for me except this brute force fix - in my case it was OK but I am aware it's ugly (and needs to be repeated if you use "Update Reference" in the future):
Since the WCF service namespace is added to your default namespace, just search and replace all mentions of the newly added
MyNamespace.ServiceNamespace
with
ServiceNamespace
in the whole solution (use your own namespaces of course), including the auto-generated Reference.cs file.
Basically, the problem is a name conflict where one name is hiding another. A folder or class named "System" can do that, but if you also have a class with the same name as your project, you'll see the same thing. Sure, you can rename everything in the reference.cs, but it's probably better to rename your conflicting class.
I had folder in my project called "System" (yes, very stupid of me) and that caused some issues in the references.cs.
Renaming the folder (and the namespace), fixed the issue.
Here is how I solve this issue on VisualStudio 2017 trying to add a reference to a web service in a test project.
After trying adding the references, rebuilding, closing, reopening and spending some time on the issue, I noticed that VS had put the files it creates to reference the WS in a folder named "Connected Services".
I renamed the folder without the space then opened all the files in the folder and the csproj with a text editor, replaced all the occurrences of "Connected Services" to "ConnectedServices" and reopened the project.
I then added references to System.Runtime.Serialization and System.ServiceModel and everything now works fine.
This is a bug in Visual Studio (still is at version 2022). To fix, remove the namespace in the reference.cs file. So if your namespace is "myapplication" and your service is "myservice", you'll see myapplication.myservice in the reference.cs file. just delete "myapplication." everywhere and make sure it isn't auto-generated again (lest you have to re-delete everything).
If you have
using XXXX.YYYY;
at the top of a C# file, do you need to include that assembly in the References part of the project?
What is the difference?
The references are needed to be added, so that they may be physically located by the compiler at compile time.
For more details watch it at http://en.csharp-online.net/CSharp_FAQ:_Why_add_a_using_statement_and_a_reference
Hope this helps.
Thanks,
Madhup
The "using" keyword is a way of avoiding having to type out the whole namespace for a class every time if it lives outside the current namespace.
For example, if I have namespace foo and I want to reference MyClass in namespace bar I can either write:
bar.MyClass = new bar.MyClass();
or
using bar;
...
MyClass = new MyClass();
The references part of the project tells the compiler which libraries outside the current project to search for the class bar.MyClass
So in short you don't need to put the using statement (but it generally makes the code easier to read and less for you to type) but you do need the referenced assembly.
You don't write using XXXX.dll at the top of a CS File.
I believe you're referring to using NamespaceX; which is a way of categorizing your classes into distinct logical partitions. So I'd group all of my Data Access classes into a namespace called MyProject.DataAccess. An assembly can contain classes belonging to multiple namespaces.
In which case, you need to reference the assembly X if you want to use some types/classes defined in assembly X with that namespace.
The using statement states you want to import a namespace into the file, giving you shorthand access. For example you can write File.Delete(file) instead of System.Io.File.Delete(file) if you imported the System.Io namespace. The namespace you are including should be available in one of your references assemblies. As fasr as I know, you can't reference DLL's directly like that from your code.