I created my custom DLL "MongoDbExtensions". Now in a new project I add a reference to the "MongoDbExtensions" and then try to invoke a method inside the MongoDbExtensions called ToDocument. I use resharper to add the namespace at the top of the file but when I compile I still get the following error:
Error 1 The type or namespace name 'MongoDbExtensions' could not be found (are you missing a using directive or an assembly reference?) C:\Projects\HelpForum\DemoConsole\Program.cs 6 7 DemoConsole
What is going wrong? My DLL can be downloaded from here:
http://github.com/azamsharp/MongoDbExtensions/downloads
UPDATE 1:
Here is the MongoExtensions class:
namespace MongoDbExtensions
{
public static class MongoExtensions
{
public static List<T> ToList<T>(this IEnumerable<Document> documents)
{
var list = new List<T>();
var enumerator = documents.GetEnumerator();
while (enumerator.MoveNext())
{
list.Add(enumerator.Current.ToClass<T>());
}
return list;
}
}
}
ToDocument is an extension method that works on Object.
I repro. This DLL was built targeting .NET 4.0. You cannot use it in a project that targets anything else but the full 4.0 .NET framework. Either targeting a lower version or the client profile will produce this error.
Since your class is called MongoExtensions, you need to change MongoDbExtensions in your test project source code to MongoExtensions.
Related
EDIT: Thank you everyone! I have never upgraded to a newer version of
.NET and language version before. Thus didn't know about .csproj
configuration. Even though I did a research before posting a question
I was not able to find a solution myself. So, I just leave these two
links for further reference, perhaps this might help someone as well.
https://learn.microsoft.com/en-us/dotnet/standard/frameworks
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version
I have upgraded to .NET 5.0.301
And finally got around to try record type in C# 9.0
I wrote a simple code but got an error during compilation.
I use Visual Studio Code as an editor.
VS Code version 1.57.0
C# extension version 1.23.12
Here is my settings.json:
"editor.semanticHighlighting.enabled": true,
"csharp.semanticHighlighting.enabled": true,
"omnisharp.path": "latest"
Set up:
dotnet new sln -n "Test"
dotnet new console -n "TestProject"
dotnet sln Test.sln add .\TestProject\TestProject.csproj
My code:
using System;
namespace TestProject
{
class Program
{
static void Main(string[] args)
{
var person = new Person() { Name = "Tom" };
person.Name = "Bob";
Console.WriteLine(person.Name);
}
}
public record Person
{
public string Name { get; set; }
public int Age { get; set; }
}
}
Problems:
CS0246 The type or namespace name 'Person' could not be found (are you missing a using directive or an assembly reference?)
CS0246 The type or namespace name 'record' could not be found (are you missing a using directive or an assembly reference?)
CS0548 '<invalid-global-code>.Person': property or indexer must have at least one accessor
CS1513 } expected
CS0116 A namespace cannot directly contain members such as fields or methods
CS1022 Type or namespace definition, or end-of-file expected
Any help much appreciated
Check your target framework and language version in your .csproj file. You should find something like:
<TargetFramework>net5.0</TargetFramework>
<LangVersion>9.0</LangVersion>
If you don't find these properties, add them inside the <PropertyGroup>...</PropertyGroup> tags. If they are set to older versions, change them.
If this does not solve your problem, you may have installed your .NET SDK incorrectly, or you may have installed it in a directory other than the default one and the VS Code C# extension is not able to find it.
I'm trying to allow a user to enter data into a textbox that will be added to the web.config file. I've added the relevent lines to the web.config file but when I make this class all goes wrong.
I keep getting the are you missing a using directive or assembly refenrence error whenever I try to run my app. I have looked at the other times this question has been asked and can't seem to figure out where I'm going wrong. The thing is that I am extremely new to Visual Studio and am just left blank at what could be the answer.
Below here is the class file that's generating the error. I hope I've included everything you need to assist me. Thank you.
using System.Collections.Generic;
using System.Linq;
using System.Configuration;
namespace WebConfigDemo
{
public class CompanyConfigSection : ConfigurationSection
{
[ConfigurationProperty("", IsRequired = true, IsDefaultCollection = true)]
public CompanyConfigCollection Companies
{
get
{
return (CompanyConfigCollection)this[""];
}
set
{
this[""] = value;
}
}
}
public class CompanyConfigElement : ConfigurationElement
{
[ConfigurationProperty("id", IsKey = true, IsRequired = true)]
public int Id
{
get
{
return (int)this["id"];
}
set
{
this["id"] = value;
}
}
[ConfigurationProperty("name", IsRequired = true)]
public string Name
{
get
{
return this["name"].ToString();
}
set
{
this["name"] = value;
}
}
} '
public class CompanyConfigCollection : ConfigurationElementCollection
{
protected override ConfigurationElement CreateNewElement()
{
return new CompanyConfigElement();
}
protected override object GetElementKey(ConfigurationElement element)
{
return ((CompanyConfigElement)element).Id;
}
}
public class CompaniesConfig
{
private static readonly Dictionary<int, CompanyConfigElement>
Elements;
static CompaniesConfig()
{
Elements = new Dictionary<int, CompanyConfigElement>();
var section = (CompanyConfigSection)ConfigurationManager.GetSection ("companies");
foreach (CompanyConfigElement system in section.Companies)
Elements.Add(system.Id, system);
}
public static CompanyConfigElement GetCompany(int companyId)
{
return Elements[companyId];
}
public static List<CompanyConfigElement> Companies
{
get
{
return Elements.Values.ToList();
}
}
}
} '
Any help is appreciated
You probably don't have the System.Configuration dll added to the project references. It is not there by default, and you have to add it manually.
Right-click on the References and search for System.Configuration in the .net assemblies.
Check to see if it is in your references...
Right-click and select Add Reference...
Find System.Configuration in the list of .Net Assemblies, select it, and click Ok...
The assembly should now appear in your references...
.Net framework of the referencing dll should be same as the .Net framework version of the Project in which dll is referred
If you've tried the above solutions and haven't found the answer, make sure that the .NET versions of all projects are the same.
I ran into this problem when importing a .NET version 4.6.1 into a .NET version 4.6.2 project. Without any warnings from Visual Basic!
More Info: The type or namespace name could not be found
Your using statements appear to be correct.
Are you, perhaps, missing the assembly reference to System.configuration.dll?
Right click the "References" folder in your project and click on "Add Reference..."
This problem would be caused by your application missing a reference to an external dll that you are trying to use code from. Usually Visual Studio should give you an idea about which objects that it doesn't know what to do with so that should be a step in the right direction.
You need to look in the solution explorer and right click on project references and then go to add -> and look up the one you need. It's most likely the System.Configuration assembly as most people have pointed out here while should be under the Framework option in the references window. That should resolve your issue.
I have observed a quote ' in your 1st line and also at the end of your last line.
'using System.Collections.Generic;
Is this present in your original code or some formatting mistake?
I had the same problem earlier today. I could not figure out why the class file I was trying to reference was not being seen by the compiler. I had recently changed the namespace of the class file in question to a different but already existing namespace. (I also had using references to the class's new and previous namespaces where I was trying to instantiate it)
Where the compiler was telling me I was missing a reference when trying to instantiate the class, I right clicked and hit "generate class stub". Once Visual Studio generated a class stub for me, I coped and pasted the code from the old class file into this stub, saved the stub and when I tried to compile again it worked! No issues.
Might be a solution specific to my build, but its worth a try.
In some cases, when necessary using has been obviously added and studio can't see this namespace, studio restart can save the day.
I was getting warnings about different versions in .NET framework; I ignored them.
The project compiles fine making the change in the solution's properties.
I'm using Visual Studio Code and could not use instructions from above so I found another way to fix the problem with referencing to namespace from another file.
All what need to be done is to add include to your .csproj file e.g:
<ItemGroup>
<Compile Include="filename.cs" />
</ItemGroup>
Then you can use namespaces from filename.cs
The following technique worked for me:
1) Right click on the project Solution -> Click on Clean solution
2) Right click on the project Solution -> Click on Rebuild solution
As part of my first experiments with C# (on Mono 2.6.7) , I am trying to use the StronglyConnectedComponents method from QuickGraph. Here is my code:
using System;
using QuickGraph;
using QuickGraph.Data;
using System.Collections.Generic;
using QuickGraph.Algorithms;
namespace Graph
{
class MainClass
{
public static void Main (string[] args)
{
IVertexListGraph<int,Edge<int>> graph;
graph = new AdjacencyGraph<int,Edge<int>>();
IDictionary<int,int> components=new Dictionary<int,int>();
int noc = graph.StronglyConnectedComponents(out components);
}
}
}
When trying to compile the code above, I get the error message (in MonoDevelop):
Error CS1061: Type `QuickGraph.IVertexListGraph<int,QuickGraph.Edge<int>>' does not
contain a definition for `StronglyConnectedComponents' and no extension method
`StronglyConnectedComponents' of type
`QuickGraph.IVertexListGraph<int,QuickGraph.Edge<int>>' could be found
(are you missing a using directive or an assembly reference?) (CS1061) (Graph)
As for as I can see from the documentation, the extension method should be available:
public static int StronglyConnectedComponents<TVertex, TEdge>(
IVertexListGraph<TVertex, TEdge> g,
out IDictionary<TVertex, int> components
)
Also, I referred all three .dll's from QuickGraph. What am I missing?
Ok, I just checked it out and it works for me on Mono 2.10.5 (Ubuntu), which I currently have, so consider updating. 2.6.7 is very old. I just downloaded quick graph library, referenced only one dll (QuickGraph.dll), copypasted your code (just removed using QuickGraph.Data) and it compiles and runs without any problem.
I created a solution called Foo.
Added a class library called Foo.Common
Added a console app to call the library code from called ConsoleApp.
I referenced the Foo.Common from ConsoleApp and typed :
using Foo.Common;
public class Program
{
CommonClass c = new CommonClass();
static void Main(string[] args)
{
}
}
and get this back :
Error 1 The type or namespace name '**Foo**' could not be found (are you missing a using directive or an assembly reference?) Z:\Foo\Solution1\ConsoleApplication1\Program.cs 3 11 ConsoleApplication1
Why am i getting this?
what s going on?
Make sure that
The ConsoleApp project has a reference to the Foo.Common project (do not browse for Foo.Common.dll),
the file contains a using directive for the namespace in which CommonClass is declared, and
CommonClass is declared as public.
So your files should look like this:
CommonClass.cs in Foo.Common project:
namespace Foo.Common
{
public class CommonClass
{
public CommonClass()
{
}
}
}
Program.cs in ConsoleApp project:
using Foo.Common;
namespace ConsoleApp
{
public class Program
{
public static void Main()
{
CommonClass x = new CommonClass();
}
}
}
Ensure that under your project settings, the target framework is set as .NET Framework 4 and not .NET Framework 4 Client Profile. I got this same behavior when it was set to Client Profile and it was fixes as soon as I set it to just the regular .NET Framework 4.
Right Click on the new console app solution/project and Add Reference and add the project that contains the Foo namespace
Did you add a reference to the library? Look under "References" in the console project. If its not there, you need to add it.
I posted this as a comment, but I want to expand on it here. What's probably happening is it's seeing using as a statement and not a keyword. It appears you have something like the following:
using System;
namespace TestNamespace
{
using Foo.Common;
public Class { }
}
Try
using System;
using Foo.Common;
namespace TestNamespace
{
public Class { }
}
Instead.
It looks like Foo Bar got this error because his project's target framework was set to the client profile.
Just thought I'd add one more 'solution' -- I created a library that targeted the 4.5 framework. My older project was tarting the 4 framework. I got this error.
Changing the older project to 4.5 made it work.
I am trying to get the executing assembly version in C# 3.0 using the following code:
var assemblyFullName = Assembly.GetExecutingAssembly().FullName;
var version = assemblyFullName .Split(',')[1].Split('=')[1];
Is there another proper way of doing so?
Two options... regardless of application type you can always invoke:
Assembly.GetExecutingAssembly().GetName().Version
If a Windows Forms application, you can always access via application if looking specifically for product version.
Application.ProductVersion
Using GetExecutingAssembly for an assembly reference is not always an option. As such, I personally find it useful to create a static helper class in projects where I may need to reference the underlying assembly or assembly version:
// A sample assembly reference class that would exist in the `Core` project.
public static class CoreAssembly
{
public static readonly Assembly Reference = typeof(CoreAssembly).Assembly;
public static readonly Version Version = Reference.GetName().Version;
}
Then I can cleanly reference CoreAssembly.Version in my code as required.
In MSDN, Assembly.GetExecutingAssembly Method, is remark about method "getexecutingassembly", that for performance reasons, you should call this method only when you do not know at design time what assembly is currently executing.
The recommended way to retrieve an Assembly object that represents the current assembly is to use the Type.Assembly property of a type found in the assembly.
The following example illustrates:
using System;
using System.Reflection;
public class Example
{
public static void Main()
{
Console.WriteLine("The version of the currently executing assembly is: {0}",
typeof(Example).Assembly.GetName().Version);
}
}
/* This example produces output similar to the following:
The version of the currently executing assembly is: 1.1.0.0
Of course this is very similar to the answer with helper class "public static class CoreAssembly", but, if you know at least one type of executing assembly, it isn't mandatory to create a helper class, and it saves your time.
using System.Reflection;
{
string version = Assembly.GetEntryAssembly().GetName().Version.ToString();
}
Remarks from MSDN http://msdn.microsoft.com/en-us/library/system.reflection.assembly.getentryassembly%28v=vs.110%29.aspx:
The GetEntryAssembly method can return null when a managed assembly has been loaded from an unmanaged application. For example, if an unmanaged application creates an instance of a COM component written in C#, a call to the GetEntryAssembly method from the C# component returns null, because the entry point for the process was unmanaged code rather than a managed assembly.
Product Version may be preferred if you're using versioning via GitVersion or other versioning software.
To get this from within your class library you can call System.Diagnostics.FileVersionInfo.ProductVersion:
using System.Diagnostics;
using System.Reflection;
//...
var assemblyLocation = Assembly.GetExecutingAssembly().Location;
var productVersion = FileVersionInfo.GetVersionInfo(assemblyLocation).ProductVersion
This should do:
Assembly assem = Assembly.GetExecutingAssembly();
AssemblyName aName = assem.GetName();
return aName.Version.ToString();
I finally settled on typeof(MyClass).GetTypeInfo().Assembly.GetName().Version for a netstandard1.6 app. All of the other proposed answers presented a partial solution. This is the only thing that got me exactly what I needed.
Sourced from a combination of places:
https://msdn.microsoft.com/en-us/library/x4cw969y(v=vs.110).aspx
https://msdn.microsoft.com/en-us/library/2exyydhb(v=vs.110).aspx