SQLiteDatabaseScope reference error - c#

Inside one solution I have SQLiteDatabaseScope correctly referenced with no errors. On the other solution I'm getting frustrated cause I cannot referenced this dll either using nuget or explicitly referencing dll on the solution one hdd location.
using System.Data.SQLite;
SQLiteDatabaseScope DbScope; // the type or namespace could not be found
any ideas ?

SQLiteDatabaseScope is not part of the SQLite adapter, but is rather from basicallyeverything or another source.
Make sure the correct assembly (from "basicallyeverything") is referenced or the appropriate class source file is included in the project.
Remember that assembly names and namespaces do not need to align in .NET - it's just a nicety when they do.

Related

Find reference for namespace in Visual Studio

I am working on a c# project. It reference quite a few packages and there are packages referencing other packages. So a namespace used in the program does not necessarily come from a direct reference.
For a specific using statement, is there a way to find out which reference (by reference, I mean the external DLL's/NuGet packages) it is originated from?
Thank you.
For example project reference a Nuget Package called Package1. In Package1 we have namespace called Namespace1. Then Package1 references Package2, which have a namespace called Namespace2.
In your code you could have
using Namespace2;
But how do you know which assembly or Nuget Package Namespace2 is originated from (in this case Package1)?
I'm not aware of a native means in Visual Studio to do this. However, JetBrains ReSharper can do this. Note that a single namespace import isn't tied to a single assembly. A namespace import (using statement) can easily bring types from several different assemblies into scope.
With ReSharper in hand I simply selected the namespace and pressed F12. You can see that System.Collections.Generic is defined in four assemblies referenced by this project.
I tried harlam357's answer in visual studio 2019 but it failed (the image bellow).
1.
Then, I did a trick. I turned the reference in to a comment and found the error line which implements a method belong the namespace. Through the method I got the root reference.
2.

CS0436 compiler warning with a shared project

We have two solutions (C#, VS2015) that consist of a few projects.
The Basic-Solution with namespace Wpf has some classes that are re-written in the More Advanced - Solution in the namespace Wpf.Advanced because the more advanced solution uses different data types for example.
Since every code-change in one of the classes, that are present in both solutions, needs to be rewritten in the second file, we decided to change the structure and use a shared project as a single place where the files should be located for both solutions.
We now use "usings" in combination with precompiler #if #else #endif blocks to merge the two files into one by changing the data types based on the project (via a compilation symbol ADVANCED).
Now to the problem:
Since some of our example projects need to reference both, the Wpf and the shared project we get the mentioned warnings CS0436 because some objects, that now exist in the shared project and in the namespace Wpf.
How can I resolve this issue?
I mean, everything works, but no warning is better than any warning, thank you!
I just had similar situation. In exe project I referenced dll and shared project. The dll in turn was referencing shared project. The solution was to exclude the shared project from the exe project. Since the shared project gets referenced from the dll the exe gets all of them too.
It may look trivial unless you are not experienced with shared projects.
The namespace NamespaceName1 in NamespaceName2 conflicts with the type TypeName1 in NamespaceName3
This error occurs when the imported type and the imported namespace have the same fully qualified name. When that duplicate name is referenced, the compiler is unable to distinguish between the two.

namespace not working in class library c#

I am trying to create a class library using some classes that I created in another project. One of the classes uses images and needs the System.Drawing namespace. However, when I try to copy the code from my project into a new class in my class library, I get an error saying the image object does not exist in the current context, and
The type or namespace name "Drawing" does not exist in the namespace System(are you missing a using directive or an assembly reference?)
It works fine in the other class as part of the other project. Why would this be?
Make sure that System.Drawing is added to the library's assembly references. By default, for class libraries, no Windows Forms assemblies are added.
Yes The problem lies in the References. If you go to your Solution Explorer and expand it, you will see a nested Folder Titled 'References'. Here is where you add the references needed in your project. To add them, simply right click the folder and select add Reference. Once here the reference you need will be in the .Net tab.
In case if a particular .NET reference is not added by default, do that manually:
using System.Drawing;
Write this in top of your class file. then also if u get error right click on reference and add reference of System.Drawing in your project.

How come I don't need to reference "System.dll" to use the "System" namespace?

I am working on an assignment that specified "Do not use any external libraries". So I created a c# application, and the first thing I did was remove all the dll's references by default... including "System.dll".
However, I can still add this to my code:
using System;
using System.IO;
I was just curious as to how come I do not need to have System.dll as a reference in my project to do this. Thanks!
mscorlib.dll includes items in both those namespaces.
You need to right-click your project > Properties > Build > Advanced... and check "Do not reference mscorlib.dll" to remove this reference.
Different assemblies can contribute to the same namespace.
Even if you don't reference System.dll, you are still referencing (implicitly) mscorlib.dll which contributes many types to the System namespace.
These references are probably defined in your Web.config or the Machine.config file so they're included by default.
These are the default libraries.I think your question is that "Dont use third party dlls"
Another thing to consider is, if you're compiling directly through the command line, a default set of switches, including default library references, is parsed by the compiler through the default response file (csc.rsp), located in the same directory as the compiler. The fact that you are able to import namespaces from the Base Class Library without explicitly referencing them at compile time is due to the fact that their containing assemblies are included in your program by default. To change this behavior at the command line, you can use the /nostdlib switch to force it not to include mscorlib.dll, or you can use /noconfig to have it ignore the entire default response file altogether. Also, I'm not too sure what you mean by system.dll, because the namespaces you mentioned are contained within mscorlib.dll. Also, I think by "external library", your instructor must have meant any 3rd party assemblies that would assist you in solving the problem. Anything that comes included with the .NET SDK would be more of a framework library. Unless your teacher is really harsh and wants you to reinvent the wheel :P

The type or namespace <blah> does not exist

Ok, I have had this one a million times before and it's been answered 1 million +1 times before.
And yet, once again. I have 3 projects, A, B, and C, each a DLL. Each project is .Net 4.0 (not the client build, full 4.0). Project C references A and B. They are referenced as projects, and the output is set to copy locally.
In C, I have two using statements in my .cs file:
using A;
using B;
When I compile, I get the complaint that is cannot find B. A is fine. B depends on A.
What the heck should I do? I've removed and re-added, closed VS2010, re-opened it, looked at the .csproj file. And I just cannot get it. Again, for the millionth time.
Someone please slap enough sense into me that I learn the source of this once and for all!
And yes, this is probably answered somewhere in StackOverflow, but not in any of the top answers I've checked so far. The terms are just too generic to be of use, too many questions where the answer is "duh, add a reference". I'm past that point.
Here are the errors I get. There are 3 kinds, but from past experience, the last one is the true one.
Error 130 'AWI.WWG.EXPMRI.MriUpload.Data.MriUpload' does not contain a definition for 'Database' and no extension method 'Database' accepting a first argument of type 'AWI.WWG.EXPMRI.MriUpload.Data.MriUpload' could be found (are you missing a using directive or an assembly reference?)
Error 114 'object' does not contain a definition for <blah>
Error 59 The type or namespace name '<blah>' could not be found (are you missing a using directive or an assembly reference?)
Aha I looked at the warnings, not just the errors, and here is what I see:
Warning 69 The referenced project '..\..\..\..\..\..\..\Partners\integration\framework\connectors\Partners.Connectors.Base\Partners.Connectors.Base\Partners.Connectors.Base.2010.csproj' does not exist. AWI.WWG.EXPMRI.MriUpload.Objects
That .csproj file is the "B" in this case. Even though I remove and re-add the project reference I get this. But it feels like I'm getting closer!
Hmm, I just found another DLL, call it "D", which "A" references. When I add it to the project, I start to get the complaint:
----------------
The Add Reference Dialog could not be shown due to the error:
The specified path, file name, or both are too long. The fully qualified file name must be less than 260 characters, and the directory name must be less than 248 characters.
----------------
Could this be related, or just another distraction?
Ok, I found the issue, though I do not understand it.
When I add the reference through the IDE, it adds this to the csproj file of "C":
<ProjectReference Include="..\..\..\..\..\..\..\Partners\integration\framework\connectors\Partners.Connectors.Base\Partners.Connectors.Base\Partners.Connectors.Base.2010.csproj">
This does not compile, it WARNS that it cannot find the referenced project, then all those ERRORs happen. But then I change the ProjectReference to the following:
<ProjectReference Include="C:\...\Partners.Connectors.Base.2010.csproj">
... and it works just fine. Note that neither of those paths are anything close to 256 characters. The fully qualified one is only 135 characters. But perhaps the IDE is doing some silly decoration of the path.
The solution has to do with the file path limits in Windows, and they way the IDE translates relative paths into full ones, as explained in this blog.
The immediate solution is to edit the csproj file manually to use the absolute path. Until the reference is re-added, the absolute path will be valid. One day I may shorten my folders, but it's not top priority at the moment.
If you suspect you have this issue, look at the Warning messages from the compiler. I often have these turned off myself, only looking at errors. But the warning about "the referenced project does not exist" was the clue that solved this for me.
In case the other link disappears, here is the link to the MS article.
http://support.microsoft.com/kb/2516078
It is worth noting that this same error manifests for a variety of issues such as client-framework-targeting issues, and is logged as a warning when a reference fails to load. Presumably the reference error is only a warning because if the reference is not actually needed it doesn't matter.
I would make sure that your project has included the references to the assemblies.
I would check that the build order matches your dependencies
Finally, if everything is setup properly, you should see the following Build Order:
Doesn't look like this is your problem, but for completeness, I should add that another thing to check (if your project targets the .NET Framework 3.5 or above) is that the Target Framework for both projects match. If you are linking something that targets the Client Profile from a full version of the Framework, you will also get a 'not found' error:
Go to warning section and resolve all warning and you are done...
The warning section will tell you what all internal dlls dependencies are needed for the project you are referencing to.
I know this isn't the answer to your issue, but the error is quite similar when you are trying to reference a project with a higher .net version than the one you're using. IE: you can't reference something with .net 4.5 from .net 3.5
Basically, this sounds like a missing reference.
Some sanity checks I can think of are:
Are you sure that the project that generates the error is C?
Are you sure you are did not make a spelling mistake in the namespace B in your using?
Can there have been some compilation error in B before compiling C? (That may cause the compiler to fail finding the namespace in B).
Do you have any other compilation error or warning?
Edit
Another suggestion: is the class in the B assembly defined as public?
I got this when updating a project that we normally use via NuGet. I thought if I simply copied the updated built dll over to the packages folder I could test it without having to setup NuGet on my machine, but it wasn't that simple because my app was still looking for the old version number. Hope that helps someone out there.
After many hours of frustration, I discovered the following process to resolve this issue with a VS2017 solution:
Insure that all reference assemblies have been recognized and have current properties.
If assemblies do not show proper reference, right click the entry
and view properties. This action often resets the reference. This
action must be completed for each project in the solution.
After resolving all references, if the error continues, delete the
following:
-The Obj folder
-The Bin folder
-Reference to the offending assembly
-Clean and Rebuild the solution. Errors should occur.
-Re-reference the needed assembly.
The editor should no longer show the namespace error and build should succeed.
Create clean project and test minimal sets of assemblies you use in your project. This way you will be sure if there is something bad in your solution or if newly created project has same symptoms. If so, then maybe VS, .net etc is corrupted or something.
I started getting this error suddenly while trying to solve another problem
I solved this by going to Solution=>properties=>project dependencies and all the dependencies were off for the two projects I was getting a namespace error for. I checked the check boxes and rebuilt the solution with no errors.
I solved this using global::[namespace][type I want to use] in C# 6.0
With VS2017, this issue came up for me when the project in my solution was unloaded.
In my case, I have to check where the "WorkFlow"1 was implemented.
Hence, I compare the framework version of the projects/class libraries that uses this "WorkFlow".
After check that all projects/class libraries uses the same framework, I have to search ".WorkFlow" in the project/class library that was causing the builing error.
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Workflow.Targets(121,5):
error : The type or namespace name 'WorkFlow' no exists in the
namespace 'Proyect_to_build' (are you missing a using directive or an
assembly reference?)
It turns out that the .dll that contains "WorkFlow" was missing in the "Reference" folder. Once added the .dll, the project/class library compiled successfully.
Again, in my case, I wasn't using this .dll and I only need compile the project/class library for enable breakpoints in a certain part of the program (where "WorkFlow" is not involved at all), but well, after add it (the .dll with the "WorkFlow" source code), it compiled.
1 "WorkFlow" comes from a legacy code using custom code for WorkFlows.

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