I have a simple console app with the namespace of
something.service.console
The problem is when I try to use
Console.WriteLine("something");
I get compile error: The Type or namespace name "WriteLine" dos not exist in the namespace something.service.console.
So unless I use
System.Console.WriteLine("something");
The C# compiler is trying to resolve the method WriteLine to the incorrect namespace ("something.service.console").
In this scenario is it possible to force the compiler to resolve the Console.WriteLine to the correct namespace "System" (instead of renaming my namespace :))?
Thank you.
The compiler will find the namespace something.service before it finds the namespace System so it will assume that
Console.WriteLine("something");
actually means
something.serviceConsole.WriteLine("something");
and hence your error.
Two possible solutions are to either fully qualify the namespace when you have issues like this:
System.Console.WriteLine("something");
or change the name of your namespace so it's not something.service.console but something.service.somethinglese.
You could "force" it like this:
using SysConsole = System.Console;
Now whenever you use Console in is refering to System.Console
public class Console
{
private void Test()
{
SysConsole.WriteLine("something");
}
}
Note: There really is nothing bad about using:
System.Console.WriteLine()
and you should avoid using classnames that already exist in the .NET Framework.
Using a C# 6 feature "using static" you can change the code to in order to avoid the ambiguous name Console without cluttering the code.
This would make sense, if a lot of System.Console.WriteLine calls occur in the code.
using static System.Console;
namespace SomeNamespace.Console
{
public class SomeClass
{
public void SomeMethod()
{
WriteLine("abc");
}
}
}
Related
So I have two dlls, Algorithms.dll and Data_Structures.dll (I made these from projects I found on GitHub). Using the browse feature I have managed to add both of the DLL files as references to my Visual Studio 2017 console project. The problem is I can't do anything else with them. Whenever I try to reference something within either file, it simply cannot be found. The only thing that is recognized is the namespace, but nothing inside of that.
What do I need to do to get VS to find the classes these DLLs contain so I can use them? I am aware I need to use Algorithms.Sorting for the example but I can't call anything so I used this as an example.
P.S. If you need more info, please ask. I'm not sure what's relevant to this issue.
EDIT: Ok, it was misleading to have that kind of example. Corrected but please read the question.
EDIT: I tried this on Monodevelop and get the same issue. Maybe it's not the IDE that's the problem?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Algorithms.Sorting; // Error, Sorting cannot be found, and neither can the file container Sorting
using Data_Structures; //Perfectly ok, can find the namespace
namespace CS_HW2_Testing_App
{
class Program
{
static void Main(string[] args)
{
// I'd like to call MergeSort and so forth here. What am I missing?!
}
}
}
Here's the top piece of the file containing MergeSort if it helps
using System;
using System.Collections.Generic;
using Algorithms.Common;
namespace Algorithms.Sorting
{
public static class MergeSorter
{
//
// Public merge-sort API
public static List<T> MergeSort<T>(this List<T> collection, Comparer<T> comparer = null)
{
comparer = comparer ?? Comparer<T>.Default;
return InternalMergeSort(collection, 0, collection.Count - 1, comparer);
}
...
In the first code block, you're importing the wrong namespace: using Algorithms.MergeSort should be using Algorithms.Sorting. Then you can use MergeSorter.MergeSort<T>(...) in your code!
You need to reference the namespace not the class.
using Algorithms.Sorting; //instead of using Algorithms.MergeSort;
Plus make sure the classes are public
I have an app which uses a specific type in a separated dll (developed by someone else).
Say it is InnerType :
namespace SeparatedAssembly
{
public class InnerType
{
}
}
Until now, I was referencing a version of this dll in Visual Studio and I was using the InnerType in my app. However, since the code inside the InnerType could change, the assembly is loaded at runtime with the "AssemblyResolve" event.
But now, the namespace of this class has changed :
namespace SeparatedAssembly.Inner
{
public class InnerType
{
}
}
So, I have an exception TypeLoadException because my app can't find this type anymore. I can't just reference this new version and change the namespace I use, because it as to be compatible with the old versions of this dll.
So my question is: is it even possible to specify the namespace to look for in an assembly, in the AssemblyResolve event?
If there is a way to catch this exception and try with a different namespace, it's also OK.
Thanks.
No, the full name of the method to be called is specified in the calling assembly, and you can't "rewrite" it in an easy way. The namespace is part of the name. I'll make a reference to another response I gave some time ago: Is C# namespace compiled into IL files to be “complete” names?.
To give an example in TryRoslyn:
namespace Foo
{
public class Bar
{
public void Zoo()
{
Console.WriteLine("Hello");
}
}
}
is translated to
.class public auto ansi beforefieldinit Foo.Bar
extends [mscorlib]System.Object
{
(the namespace Foo is directly part of the name Foo.Bar)
and then the method call to Console.WriteLine is:
call void [mscorlib]System.Console::WriteLine(string)
Copied some code from one controller to another. Both files have the same using statements but it wont 'resolve' this issue for me.
On my first file address.Name.Value = source.Name.TrimSafe();
is fine however on my second file. .TrimSafe flags up as does not exist
From the telescense i can choose trim, trimEnd or trimStart where has trimSafe gone to and why cant I use it?
TrimSafe() is not a standard .NET method. This would suggest that TrimSafe() exists as a method in your first file, but never got copied over to the second, and it's a either a private function or non-static function.
I would clean & rebuild your project as well.
It sounds like a namespace issue to me.
Consider this:
// In some file somewhere
namespace firstNamespace
{
Class MyString : String
{
public static TrimSafe() {}
}
}
// The first file you copied from
namespace firstNamespace
{
public void foo() { TrimSafe(); } // Works!
}
namespace secondNamespace
{
public void fee() { TrimSafe(); } // Nope :(
}
To fix the last one, you need to add using firstNamespace; at the top with the other using statements. The reason would be that the first file you're copying from is in the same namespace as where TrimSafe is defined.
In C++ you typically #include all of the referenced .h files for each class that you use.
In C#, you don't add using statements for classes, but instead for namespaces. You only need to be using the namespace, and everything inside of that namespace comes along with it. Anything defined in namespace xyz sees everything else defined in namespace xyz without having to have a using for each class.
Your second file is in a different namespace, and so it has no idea what is in the first namespace, and so it doesn't see TrimSafe.
That's my guess anyways.
Looks familiar, I guess you're doing the Orchard Webshop tutorials as well :)
You need to add a folder in your project called Helpers, and it should have this class in it:
public static class StringExtensions {
public static string TrimSafe(this string s) {
return s == null ? string.Empty : s.Trim();
}
}
Just include the namespace where your method is needed.
Is there a way to reference a certain class/interface/... by enclosing it with its namespace rather than a using directive "using namespace_name" ?!
As, I'm working on a website, which uses SAP .NET connector. I already added a reference for connector ddl, and while referencing its namespace "using namespace_name", or set class namespace to another one rather than connector namespace,
I got error regarding connector classes with that error message "The type or namespace couldn't be found, are you missing a using directive or an assembly reference?".
But while changing namespace name to connector namespace, everything is going well?!
// Set namespace to be IDestinationConfiguration interface namespace.
// Using this, everything is going well.
namespace SAP.Middleware.Connector
{
public class ConnectorConfiguration : IDestinationConfiguration
{
}
}
// Using that way; it's not working, and got an error regarding IDestinationConfiguration even it belongs to refernced namespace.
using SAP.Middleware.Connector;
public class ConnectorConfiguration : IDestinationConfiguration
{
}
So, connector types forced me to set namespace of class to their namespace!
Is this possible? If so, how?
I ran into this too and couldn't figure it out until I finally found the answer on a post at http://forums.sdn.sap.com/thread.jspa?threadID=1876430, the last line which said:
"Also, make sure your target framework is ".NET v4.0" NOT ".NET v4.0 Client" -- that way you get the System.Web namespace that is required."
My project was targeting 4.0 client target framework. Once I changed it to just .NET Freamework 4.0, all the references worked as expected.
Is this what you are after?
public class ConnectorConfiguration: SAP.Middleware.Connection.IDestinationConfiguration
{
}
You can write all your code without usings if you like, you just need to use the fully qualified namespace name for every class/interface where the using isn't used.
If you try this:
using SAPTEST = SAP.Middleware.Connection;
namespace TestNamespace
{
public class ConnectorConfiguration: SAPTEST.IDestinationConfiguration
{
}
}
If that works, but it doesn't work if you remove SAPTEST, then IDestinationConfiguration must be declared in another namespace too.
Using .NET 2.0, C#, Windows Forms development, Enterprise Library 3.1.
We have a project namespace (call it Project). We also have several sub-namespaces inside of that project, for example Project.Namespace1, Project.Namespace2, etc.
In one class, we define enums and such to be used with the Enterprise Library Logging block, like this:
namespace Project.Logging
{
public static class Logging
{
public enum LogPriority
{
// enum values here
}
}
}
In another class, I use the enum values so I need to declare a using statement. Same project, so there is no assembly to reference, right?
If I declare the using inside of the local namespace, like this, it works fine:
namespace Project.SomeName
{
using Project.Logging;
// code referencing the Logging enum
}
However, if I put the using statement outside of the local namespace declaration, I get the "type or namespace name 'LogPriority' does not exist in the namespace 'Project.Logging'... Like this:
using Project.Logging;
namespace Project.SomeName
{
// code referencing the Logging.LogPriority.whatever
}
Why is this? Has anyone run across this before?
I have run into similar (though not exactly the same) problems before when using a class that has the same name as its namespace.
Oddly enough it seemed to compile ok on some developers pc's but not on others. In the end we made sure that no namespace contained a class of the same name.
namespace Project.Logging
{
public static class Logging // this is what caused the probems for me
{
}
}
I also had a wired error. I cannot find any namespace which is coming from different assemblies, but begins with executing assembly name.
Finally, I found out that I have set the target framework to .NET framework client profile.
Yes, most likely you have an unusual value set for the "Default Namespace" in your project properties. I would validate the project configuration.
We ran into this issue before and it all went down to ambiguous naming of the namespace and the class name.
When we tried to have our namespace as Services.Web.xxx and also add in a service reference as Services.Web.xxxx and ALSO add a references to an assembly that was named Services.Web.xxx you can only imagine the problems we ran into.
In the end to fix it we simply did a rename to make sure that there was only one instance of the Services prefix
Also you could do the following and create an alias to LogPriority to LogEnum:
using LogEnum= Project.Logging.Logging.LogPriority;
namespace Project.SomeName
{
internal class MyClass
{
public MyClass()
{
LogEnum enum1 = LogEnum.None;
}
}
}
namespace Project.Logging
{
public static class Logging
{
public enum LogPriority
{
None,
Default
}
}
}
It definitely can make a difference if you have usings inside or outside the namespace. There is a good discussion here, and it is likely to be related to your default namespace settings.