I have a C# file A which defined some public enum and public struct. Now I need to define errorCode for them. I defined an enum named SubsystemErrorCode in file B. Both A and B don't have class inside. They are in the same namespace In one struct of file A, I try to use the SubsystemErrorCode enum but it give me error tell me :
Error 1 The type or namespace name 'SubsystemErrorCode' could not be found (are you missing a using directive or an assembly reference?)
If I move that SubsystemErrorCode into the same file. no error. But I really want them to be separated. How can I do this? thanks,
File A:
namespace SystemSoftware {
public struct StatusMessageBody {
public ProcessControlStatus State;
public StatVal LVP_OK;
public SubsystemErrorCode LVP_ERROR_CODE;
}
}
File B:
namespace SystemSoftware
{
//public class ErrorCode
//{
public enum SubsystemErrorCode : byte
{
NoError = 0,
EPCSS_CPU_ERROR = 1,
LVPS_ERROR
}
//}
}
The only reason for your problem is if the files, A and B, are not in the same project.
In this case the project that has the File A has to reference the project where File B is defined.
Think you are missing a USING statement or have not added a reference to the library.
Change your enum file to this
namespace SystemSoftware.Enums
{
public enum SubsystemErrorCode : byte
{
NoError = 0,
EPCSS_CPU_ERROR = 1,
LVPS_ERROR
}
}
and in your File A put this up the top (under using System;)
using SystemSoftware.Enums;
or you could asl try in File A
public SystemSoftware.Enums.SubsystemErrorCode LVP_ERROR_CODE;
instead of
public SubsystemErrorCode LVP_ERROR_CODE;
Edit: Forgot to say, I'm assuming that both File A and File B are in the same project?
If not, you will need a reference in Project A, to Project B
Ok Edit Again.
I Created Two Files, like you say, in the same project. It works, here they are.
File1.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace SystemSoftware
{
public struct StatusMessageBody
{
public SubsystemErrorCode LVP_ERROR_CODE;
}
}
File2.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace SystemSoftware
{
//public class ErrorCode
//{
public enum SubsystemErrorCode : byte
{
NoError = 0,
EPCSS_CPU_ERROR = 1,
LVPS_ERROR
}
//}
}
Related
So I made a .dll which I added to my project everything works, but when I try to use any of the class from my .dll. I have to specificly use namespace.classname instead of being able to just say Classname even when I put at the top of my project
using namespace
using System;
using MyTestClassLibrary;
using System.IO;
using YangHandler;
namespace UsingMyclassdll
{
class Program
{
static void Main(string[] args)
{
YangHandler.YangHandler yangh = YangHandler.YangHandler.Parse("Rawtext");
Console.ReadKey();
}
}
}
At the line of using Yanghandler visual studio says
Using directive is unnecessary
Isn't this what using is exactly used for to use other namespaces?
YangHandler code
using System;
using System.IO;
namespace YangHandler
{
public class YangHandler
{
public string YangAsRawText { get; private set; }
public static YangHandler Parse(string YangAsRawText)
{
YangHandler handlerToReturn = new YangHandler();
handlerToReturn.YangAsRawText = YangAsRawText;
return handlerToReturn;
}
I know that it could be solved by using namespace aliases under the namespace "UsingMyclassdll" like
using YangHandler = YangHandler.YangHandler;
But isn't there a more normal solution?
Check this very interesting piece of documentation from Microsoft: https://learn.microsoft.com/en-us/dotnet/standard/design-guidelines/names-of-namespaces
DO NOT use the same name for a namespace and a type in that namespace.
For example, do not use Debug as a namespace name and then also provide a class named Debug in the same namespace. Several compilers require such types to be fully qualified.
So your work around is basically defining the fully qualified name as the type and namespace are of the same name.
No work around for this. The compiler can't know if you mean the one or the other.
When I'm trying to import a namespace from another file, the compiler gives me the error message, "type or namespace name could not be found". Take a look at my code below. Both files are in the same directory, so I don't understand what's wrong.
Setup.cs (the main file)
using System;
using ScreenTextLine; // Error is here.
namespace Setup
{
namespace Screen
{
class Text
{
static void Main(string[] args) { }
}
}
}
Problem.cs (the file with the namespace I'm trying to import)
using System;
namespace Setup
{
namespace ScreenTextLine
{
class WelcomeText
{
static void Main(string[] args){}
}
}
}
You need to use their fully-qualified name when referencing them by separating each namespace by a dot using the following format...
[Top_level_namespace].[nested_namespace]
So, this nested structure...
namespace Setup
{
namespace Screen
{
}
}
It's referenced by a using statement this way...
using Setup.Screen;
I am having a DLL file. With the use of DLL, I have to call the methods and add some more methods in my project. Now, I need to migrate the older DLL to Make that project as a new DLL. I done this But the problem is The C# code is converted to net module it shows two errors. I am not clear about that. kindly help me over it.
DLL Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace mcMath
{
public class mcMathComp
{
private bool bTest = false;
public mcMathComp()
{
// TODO: Add constructor logic here
}
/// <summary>
/// //This is a test method
/// </summary>
public void mcTestMethod()
{ }
public long Add(long val1, long val2)
{
return val1 - val2;
}
/// <summary>
/// //This is a test property
/// </summary>
public bool Extra
{
get
{
return bTest;
}
set
{
bTest = Extra;
}
}
}
}
CS Project:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using mcMath;
namespace mcClient
{
class Program
{
static void Main(string[] args)
{
mcMathComp cls = new mcMathComp();
long lRes = cls.Add(23, 40);
cls.Extra = false;
Console.WriteLine(lRes.ToString());
Console.ReadKey();
}
}
}
Errors:
Program.cs(5,7): error CS0246: The type or namespace name 'mcMath' could >not be found (are you missing a using directive or an assembly reference?)
Tried Methods:
I will add the reference via Project-> Add Reference.
The using Reference also used.
Put the DLL into the current project debug/release folder
I'm guessing you used to have the code side by side, i.e.
public int Add(int a, int b)
{
return a + b;
}
public void SomeMethod()
{
var result = Add(2,3);
}
This works because the scope (this.) is applied implicitly, and takes you to the Add method on the current instance. However, if you move the method out, the scope is no longer implicit.
You will need one of:
the type name if it is a static method
or a static using if using C# 6
a reference to the instance if it is an instance method
Then you would use one of (respectively):
var result = YourType.Add(2,3); (plus using YourNamespace; at the top)
using static YourNamespace.YourType; at the top
var result = someObj.Add(2,3);
Checking the compiler message, it sounds like you've done something like (line 7):
using YourNamespace.YourType.Add;
which is simply wrong; you don't use using to bring methods into scope - only namespaces and (in C# 6) types.
Likewise, I suspect you have (line 22):
var result = YourNamespace.YourType.Add(x,y);
which is not valid as this is not a static method.
Create and Using DLL in same Project in c#
DLL or Class Library is a separate project that can be part of same solution.
As you already know, adding a reference to that dll/project will make it available in your app project.
However if function Add in dll is in different namespace (which would be normal) u would need to add using clause at the beginning of your class
I have this class file call SMSHelper.cs First I just wanted to know is my written structure is Correct or Wrong?(My class file name is also SMSHelper.cs & my first class also SMSHelper here you can see in the code.).
Basically I have 3 classes in same file. One class has the same name as the file name.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Text;
using System.Text.RegularExpressions;
namespace SMSBase.SMSFunction
{
public class SMSHelper : DotNetNuke.Entities.Modules.PortalModuleBase
{
// Some Code here
// Return Something here
}
public class Validator
{
public bool IsValidate(string Item)
{
// Some Code Here Not return anything
}
public class HuntingDate
{
//Implementation & Constructor here.. Return Something
}
}
}
There is nothing wrong in your class structure (except one missing bracket). And there is no matter your class name and file name are same. You can access and initialize your class objects like that...
SMSBase.SMSFunction.SMSHelper objSMSHelper = new SMSBase.SMSFunction.SMSHelper();
SMSBase.SMSFunction.Validator objValidator = new SMSBase.SMSFunction.Validator();
SMSBase.SMSFunction.HuntingDate objHuntingDate = new SMSBase.SMSFunction.HuntingDate();
This SMSBase.SMSFunction is your namespace... you can access classes by your namespace or include this namespace in the class header like
using SMSBase.SMSFunction
There is a problem in opening closing brackets:
namespace SMSBase.SMSFunction
{
public class SMSHelper : DotNetNuke.Entities.Modules.PortalModuleBase
{ // Some Code here // Return Something here
}
public class Validator
{
public bool IsValidate(string Item)
{ // Some Code Here Not return anything
}
}
public class HuntingDate
{ //Implementation & Constructor here.. Return Something
}
}
If that is what you are asking.
Yes as Talha ,said one bracket is missing.Try to put that.
When we want to call the class name its better to call with "namespace.ClassName" format which gives clarity to the compiler.
I have created a Area class using Linq-to-SQL.
Now I want to create a partial class of the same name so I can implement validation.
Error 1 Cannot implicitly convert type
'System.Data.Linq.Table<SeguimientoDocente.Area>'
to
'System.Linq.IQueryable<SeguimientoDocente.Models.Area>' C:\Users\Sergio\documents\visual
studio
2010\Projects\SeguimientoDocente\SeguimientoDocente\Models\AreaRepository.cs 14 20 SeguimientoDocente
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace SeguimientoDocente.Models
{
public class AreaRepository
{
private SeguimientoDataContext db = new SeguimientoDataContext();
public IQueryable<Area> FindAllAreas()
{
return db.Areas;
}
public Area GetArea(int id)
{
return db.Areas.SingleOrDefault(a => a.ID == id);
}
public void Add(Area area)
{
db.Areas.InsertOnSubmit(area);
}
public void Delete(Area area)
{
db.Areas.DeleteOnSubmit(area);
}
public void Save()
{
db.SubmitChanges();
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace SeguimientoDocente.Models
{
public partial class Area
{
}
}
Here's a screenshot.
This is almost certainly because your partial class is not in the right namespace. Go into the .designer.cs file of the LINQ model, look for the generated Area class, and make sure the namespace you wrapped your partial class in matches.
EDIT
I just fixed the formatting in your question. The error message does in fact indicate that your partial class is in the wrong namespace.
Error 1 Cannot implicitly convert type
'System.Data.Linq.Table<SeguimientoDocente.Area>'
to
'System.Linq.IQueryable<SeguimientoDocente.Models.Area>'
As you can see from the error above, you need to change the namespace your partial class is in to be SeguimientoDocente, not SeguimientoDocente.Models. As it stands now, they are two completely different incompatible types that happen to have the same simple name.
The error message tells you that the problem is in line 14 of the AreaRepository.cs file. Specifically, you are trying to return db.Areas from a method whose return type is IQueryable<Area>, though db.Areas is in fact of type System.Data.Linq.Table.