I am working on a REST WCF project and when I implement the following code, it complains that it can't resolve the WebGet class? What am I missing?
I tried importing the System.ServiceModel.Web namespace but it can't find it even though I referenced it. The "Web" in System.ServiceModel.Web does not register when I register it in a using statement on top of my code.
Basically, what do I need to implement such WCF REST concepts like WebGet, WebInvoke, UriTemplate, etc?
UPDATE: After some feedback and thinking about this a little bit more what I've done, it seems that the DLLs (System.ServiceModel & System.ServiceModel.Web) do not come up via the 'Add Reference' window when I go to add a project reference. When I first started the project, FYI, since these assemblies did not come up at first, I went 'searching' for them, and copied them to a temp folder so I can reference them and thus, I guess I am having the resolve issues. So, now that I am at this point, how can I get my VS to recognize/register these WCF REST DLLs? Thanks!
UPDATE: I believe I am update-to-date on everything: developing on VS 2008 SP1 - I try to download the latest SPs, downloaded the REST Preview 2 Starter Kit, developing against 3.5 Framework, trying to create a WCF REST layer to ultimately be consumed by Silverlight 2 client.
This is what I have:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using UtilityClasses;
using Microsoft.ServiceModel.Web;
using Microsoft.Http;
namespace WcfRestService
{
[ServiceContract]
public interface IRestService
{
[OperationContract(Name = "Add")]
[WebGet(UriTemplate = "/")] // ** can't compile here **
int Add();
}
}
Any advice will be greatly appreciated it.
You need to reference the System.ServiceModel.Web DLL.
Right-click the 'References' folder in your project and choose 'Add Reference...'. Scroll down to System.ServiceModel.Web and click 'OK'.
Just a one thought, you might be targeting your project to .Net Client Profile which exposes limited namespaces. you may need to check the target framework setting at your project properties.
I have faced that with a WCF project not finding System.ServiceModel.Web untill I changed the default framework settings.
HTH
This happened to me too.
I did this:
Delete System.Service.Web from References
Build
Clean Project
Add System.Service.Web to References
Build
..and VS found it??
In "project properties" make sure your "target framework" is set to : .NET Framework 4
and not: .NET Framework 4 Client Profile, or any lower .NET version.
Also, if possible use VS 2010.
--DBJ
right click on the project name and choose Properties.
change the target framework to .NET Framework 4.
right click on the References and choose Add Reference.
And then you can see System.ServiceModel.Web.
By default the target framework is .NET Framework 4 Client Profile,
so you cannot find the System.ServiceModel.Web.
I had the same problem.
I have added this missing reference:
System.ServiceModel.Web
and this code line:
using System.ServiceModel.Web;
and all got solved! ;)
using System.ServiceModel.Web;
In my case my project was building despite this warning in the designer view of the service class. Not really a big issue, but still pretty annoying. Realised it was just ReSharper playing up - it hadn't updated its internal cache when the reference to System.ServiceModel was added automatically by VS when I added a new WCF Service. I turned off real-time code analysis in:
Tools -> Options -> Resharper Ultimate -> Options -> Code Inspection->
Settings -> Enable code analysis
This restored the built-in VS code analysis, and problem was fixed straight away.
If you'd prefer to keep using ReSharper code analysis, clearing the cache in:
Tools -> Options -> Resharper Ultimate -> Options -> Environment ->
General -> Clear Caches
may also sort the issue.
Related
Running VSPro 2013 on a x64 Win7 machine, creating a C# Console Application called PROJ, using .NET4 and using a class library I build IN THE SAME PROJECT. Class lib is called CHILD1 in CHILD1NAMESPACE. In PROJ, I have using CHILD1NAMESPACE; and it works!
I then created CHILD2, in CHILD2NAMESPACE... IN THE SAME PROJECT... with the exact same settings as CHILD1 (.NET4 / Class Library).
using CHILD2NAMESPACE; gives me an error! The Type or namespace CHILD2NAMESPACE could not be found...
I've searched the web and most resolutions include switching frameworks because the class library and parent are using different frameworks. In my case, they are all using .NET4 (not client) and are within the same Project. I've restarted VS several time... cleaned, re-built etc.
Any clues would be appreciated.
Thanks
-Ed
It looks like you created two projects (csproj) inside one solution.
In order to make one project access the other one you must add a reference between the projects.
In orde to do that, right click over the the project that is not building and click on "Add reference" you can choose the solution and select the project being referenciated.
I am working on an Asp.Net MVC 4 Application in which I am using SignalR 2.0.1 and I Mapped it using Owin Startup class and it worked fine at first.
All of a sudden when I tried to rebuild my app it said that the type are namespace IAppbuilder could not be found.
Following is my start up class
using Microsoft.Owin;
using Owin;
using WhiteBoardApp;
namespace WhiteBoardApp
{
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapSignalR();
}
}
}
I have installed Owin package too, and for some reasons I could not find Owin Startup class so I just added a normal class and included all the references that are needed.
May I know where I am making a mistake
Try to use Package Manage Console and do
Update-Package Owin -Reinstall
I was having similar issue. But instead Owin, problem was causing Microsoft.Owin, obviously
Update-Package Owin -Reinstall
Didn't work, neither did Update-Package Owin
BUT
Install-Package Microsoft.Owin
did work fine for me, thanks.
The IAppBuilder interface is found under Owin package. Just add a reference in your class file:
using Owin;
And rebuild. Your project will pick this up.
I have no idea why VS didn't pick this up, but it didn't. Once I added this reference to my project, then everything fell into place.
I encountered the same problem while building my project. Here are the steps that helped fix my problem:
Go to Solution Explorer and look for your project
Under your project, expand the References; You should see warnings on the problematic reference
Right click References and open Manage NuGet Packages
Search the name of problematic reference i.e. Microsoft.Owin; After loading it shows that it is already installed (It is, but it installed incorrectly. Checking the properties > version at step 2 shows 0.0.0.0)
Check Force uninstall, even if there are dependencies on it
Uninstall
Install
Build and run the project
Problems
Cannot install Microsoft.Web.Infrastructure because it already exists in the packages folder. Rolling back...
Go to your project folder and look for packages
Find the problematic package i.e. Microsoft.Web.Infrastructure
Delete the folder
Resume from step 7
Alternatives
Here are the alternatives I've read about to fix this kind of problem.
Clean and Rebuild Project / Solution
Restart Visual Studio
Restart PC
Good luck.
My Visual Studio 2013 for some reason didn't realize that the references paths existed. The yellow exclamation mark in front of the references was shown for all the added packages. I checked ../packages/ but all files existed, i also opened the .csproj file which referenced the correct paths.
Closing and opening the solution returned quite a lot of errors, and could not load the projects included in the solution.
Restarting Visual Studio 2013 saved the day for some unexplained reason.
My following using's equivalent in F# present a problem of hiding the IAppBuilder. It turns out that the Owin stipulation was being interpreted as an incomplete System.Web.Http.Owin reference, even though the Owin.dll providing the Owin namespace was referenced.
open System.Net.Http
open System.Web.Http
open Microsoft.Owin
open Owin
The problem was resolved by rearranging the usings as follows:
open Microsoft.Owin
open Owin
open System.Net.Http
open System.Web.Http
...granted, this may be a bug peculiar to the F# compiler and name conflicts are handle better in C# and elsewhere.
In my case, I had moved around the project folders and the location of the vs solution file (.sln). Once I was done with re-adding the projects, there was a packages folder on the solution level and one was left in a project sub folder.
This way, in that project, the relative package folder links in the .csproj file got messed up.
The reinstallation or other tips regarding the nuget package manager in this thread were helpful. I noticed, that after I reinstalled a few packages, in my git source code diff, the path of the packages folder was changed within the csproj file.
Before
<HintPath>packages\Microsoft.Owin.4.0.1\lib\net45\Microsoft.Owin.dll</HintPath>
After
<HintPath>..\packages\Microsoft.Owin.4.0.1\lib\net45\Microsoft.Owin.dll</HintPath>
So, if you run in the same issue and you have a lot of nuget packages, it might be easier to close the whole solution, open the csproj file(s) in a text editor like vscode and fix the relative links with search and replace. Then just save, close, reopen solution in VS and restore nuget packages. That should do the trick.
(In any case, you should delete the local packages folder on the project level, so that the project really fails, if it does not get the right packages.)
It's an ordering issue.
using Microsoft.Owin;
using Owin;
Leads to Microsoft.Owin to be defined first, then Owin is found under already imported Microsoft namespace. If you mouse over Owin of using Owin you should see it was resolved to Microsoft.Owin again and furthermore IDE will gray out using Owin as redundant unused reference.
Do:
using global::Owin;
Which clarifies for the compiler not to look for Owin under already defined namespaces (e.g. Microsoft. namespace).
http://www.asp.net/signalr/overview/getting-started/tutorial-getting-started-with-signalr
Check for the visual studio you are using
You can find the following comment
Note: If you are using Visual Studio 2012, the SignalR Hub Class (v2) template will not be available. You can add a plain Class called ChatHub instead.
Also
Note: If you are using Visual Studio 2012, the OWIN Startup Class template will not be available. You can add a plain Class called Startup instead.
I'm trying to use DataAnnotations in my WPF project to specify a maximum length of strings, with the following:
using System.ComponentModel.DataAnnotations;
However, I get the error
The type or namespace name 'DataAnnotations' does not exist in the
namespace 'System.ComponentModel' (are you missing an assembly
reference?)
I've seen other examples where DataAnnotations does exist in this namespace. I'm using C#4. Is there any reason why I can't use this? What can I do to fix it?
You have to reference the assembly in which this namespace is defined (it is not referenced by default in the visual studio templates). Open your reference manager and add a reference to the System.ComponentModel.DataAnnotations assembly (Solution explorer -> Add reference -> Select .Net tab -> select System.ComponentModel.DataAnnotations from the list)
If using .NET Core or .NET Standard
use:
Manage NuGet Packages..
instead of:
Add Reference...
To Reference System.ComponentModel.DataAnnotations
In a code file to have Using System.ComponentModel.DataAnnotations; at the top of the file such as:
using System.ComponentModel.DataAnnotations;
Add a .NET reference to your project by right clicking the project in solution explorer:
Hope this helps! This question helped me.
If you don't have it in references (like I did not) you can also add the NuGet System.ComponentModel.Annotations to get the assemblies and resolve the errors. (Adding it here as this answer still top of Google for the error)
I also had the same problem and I resolved by adding the reference in one of my projects which didn't had the mentioned reference. If you have 2-3 projects in your solution, then check by adding this reference to the other projects.
I found that I cannot reference System.ComponentModel.DataAnnotations from Silverlight 5 with the below version at (1). I found that Silverlight 5 assemblies cannot use .NET assemblies, it gives the error "You can't add a reference to System.ComponentModel.DataAnnotations as it was not built against the Silverlight runtime. ..." I plan to workaround this by hopefully installing the Silverlight 5 package found at (2) below. If this fails I will update this post.
[UPDATE: it failed. I installed everything relating to Silverlight 5 and I don't have the Silverlight version of the .dll assembly System.ComponentModel.DataAnnotations . Too bad. UPDATE II: I found an old .dll having this name from a previous installation of Silverlight developer's kit for Visual Studio 2008 or 2010. I added this file and it seems to 'work', in that IntelliSense is now recognizing attributes on class members, such as [Display(Name = "My Property Name")]. Whether or not this works for everything else in this .dll I don't know.]
(1)
Microsoft Visual Studio Professional 2013
Version 12.0.21005.1 REL
Microsoft .NET Framework
Version 4.5.51641
Installed Version: Professional
(2)
http://go.microsoft.com/fwlink/?LinkId=229318
I searched for help on this topic as I came across the same issue.
Although the following may not be the Answer to the question asked originally in 2012 it may be a solution for those who come across this thread.
A way to solve this is to check where your project is within the solution. It turns out for my instance (I was trying to install a NuGet package but it wouldn't and the listed error came up) that my project file was not included within the solution directory although showing in the solution explorer. I deleted the project from the directory out of scope and re-added the project but this time within the correct location.
Use the FrameWork version 4.5 and above for your project then problem solved.Because this namespace is under 4.5 and above.
System.ComponentModel.DataAnnotations is contained in its own assembly so you need to make sure you have it refernced. Just simply:
1). Right click on Soloution and choose add.
2). Choose reference from the list.
3). Search " System.ComponentModel.DataAnnotation " and tick the check box on its left hand side and press ok.
Job done, shouldnt have any refernce errors.
If you tried to update visual studio from vs2008 to vs2010. And your app uses framework 3.5 (and you don't want to upgrade it), and also used WCF RIA Services BETA... I have bad news... you MUST upgrade to WCF RIA Services v1 (BETA does not work on vs2010)... and due to this... you also have to install Silverlight 4 + upgrade to framework 4.0
See this:
http://blog.nappisite.com/2010/05/updating-visual-studio-2008net-35-ria.html
I upgraded from Silverlight 4 to Silverlight 5 and then I was having this issue. Although I had a reference to "System.ComponentModel.DataAnnotations" under "References" in my project, it had a yellow yield sign by it that indicated the previously referenced assembly could not be found. It turned out that the properties of the "System.ComponentModel.DataAnnotations" reference indicated "Specific Version = True", when I changed this to "Specific Version = False" it fixed the issue. Right click on the "System.ComponentModel.DataAnnotations" assembly under "References" and select "Properties" from the context menu. Check that the property value for "Specific Version = False".
It must have been referencing the old Silverlight 4 assembly which was no longer available after the upgrade to Silverlight 5.
I also have this problem.
That is very stupid when i add a namespace the same with System. I try to remove all references, but it is not resolved. I use "global::System.ComponentModel", it is working as well.
When i remove my namespace, this problem has been resolved.
For .Net Core in Visual Studio 2019 try this.
see VS suggestion
It worked for me, hope it'll work for you as well.
I was moving from .Net Framework 4.7.2 to .Net Standard 2.0.
In my case, I had to change DataAnnotations's reference from an Assembly reference to a Nuget package.
This error occurs when the reference to the "System.dll" got removed.Solution to the problem is very simple add the reference to "System.dll".The dll is normally available in the following location
"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727" .Add the reference your problem will get solved .
There was a problem using System.ComponentModel.DataAnnotation in net40 so I just did:
#if !NET40
using System.ComponentModel.DataAnnotations;
#endif
#if !NET40
[StringLength(256)]
#endif
The NET40 must be a predefined macro definition for .Net Framework 4.0
I had same problem, I solved this problem by following way.
Right click on page, select Property. in build action select Content.
Hope that this solution may help you.
I have a string that I'd like to encode into the standard URL format. From what I've found, I should be able to do this via the httpUtility.urlEncode method, but I don't seem to have that available.
I've added "using" references to both System.Web and System.Net to no avail. I've also seen other references to server.urlEncode amongst other variants, but I don't see the method anywhere.
I'm using the latest version of C# in Visual Studio 2010. Is the method called something different in this version, hidden somewhere else, or am I completely off base?
By default, new projects in Visual Studio 2010 target the .NET Framework 4.0 Client Profile, which does not include the System.Web assembly.
You can change the version of the Framework that your project targets in your project's Properties. Under the "Application" tab, select ".NET Framework 4.0" from the combobox labeled "Target framework".
Then, make sure that you have added a reference to System.Web using the "Add Reference" dialog.
Finally, add a using directive to the top of your class for the System.Web namespace:
using System.Web;
You'll find the various overloads of the UrlEncode method in the HttpUtility class. Sample code:
HttpUtility.UrlEncode("http://www.google.com/");
In .Net 4.5 you can (should?, 'please use' says a Katana comment) use the System.Net.WebUtility.UrlEncode method.
It can't be named differently since Visual Studio doesn't supply the class or method names, the .NET framework does.
All I can tell you is that the System.Web.HttpUtility AND System.Web.HttpServerUtility classes contain a method called UrlEncode(string).
If your project target ".NET Framework X Client Profile",you cannot not use "System.Web",but you can use "Uri.EscapeUriString | Uri.UnEscapeUriString" instead.
Yes, adding the reference was my answer. But be sure you double check the project, that it is in, if you have more than 1 project in your solution. I had a solution with 3 projects. System.Web was added to 2 projects but not the 3rd project.
I spent an hour trying to figure out why I couldn't use HttpUtility since it was a Reference in the main project. But I didn't check the sub-projects of the Solution.
Hope it helps someone.
Because you only see AspNetHostingPermission, AspNetHostingPermissionAttribute, and AspNetHostingPermissionLevel, I strongly suspect (like the other guys) that you're missing a reference.
The best you can do is start a new project, because it's pretty complicated to add/remove references without ruining your entire project.
How to: Add or Remove References in Visual Studio (MSDN) shows how to add/remove references. In your case, you should check/add the System.Web reference.
This question already has answers here:
Getting "type or namespace name could not be found" but everything seems ok?
(44 answers)
Closed 8 years ago.
I have a C# solution with several projects in Visual Studio 2010.
One is a test project (I'll call it "PrjTest"), the other is a Windows Forms Application project (I'll call it "PrjForm"). There is also a third project referenced by PrjForm, which it is able to reference and use successfully.
PrjForm references PrjTest, and PrjForm has a class with a using statement:
using PrjTest;
Reference has been correctly added
using statement is correctly in place
Spelling is correct
PrjTest builds successfully
PrjForm almost builds, but breaks on the using PrjTest; line with the error:
The type or namespace name 'PrjTest' could not be found (are you missing a using directive or an assembly reference?)
I've tried the following to resolve this:
Removed Resharper (since Resharper had no trouble recognizing the referenced project, I thought it might be worth a shot)
Removed and re-added the reference and using statement
Recreated PrjForm from scratch
PrjForm currently resides inside the PrjTest folder, I tried moving it to an outside folder
Loaded the solution on a different computer with a fresh copy of VS 2010
I have done my homework and spent far too long looking for an answer online, none of the solutions has helped yet.
What else could I try?
See this question.
Turns out this was a client profiling issue.
PrjForm was set to ".Net Framework 4 Client Profile"
I changed it to ".Net Framework 4", and now I have a successful build.
Thanks everyone!
I guess it figures that after all that time spent searching online, I find the solution minutes after posting, I guess the trick is knowing the right question to ask..
In my case I had:
Referenced DLL : .NET 4.5
Project : .NET 4.0
Because of the above mismatch, the 4.0 project couldn't see inside the namespace of the 4.5 .DLL. I recompiled the .DLL to target .NET 4.0 and I was fine.
PrjForm was set to ".Net Framework 4 Client Profile" I changed it to ".Net Framework 4", and now I have a successful build.
This worked for me too. Thanks a lot. I was trying an RDF example for dotNet where in I downloaded kit from dotnetrdf.
NET4 Client Profile:
Always target NET4 Client Profile for all your client desktop applications (including Windows Forms and WPF apps).
NET4 Full framework:
Target NET4 Full only if the features or assemblies that your app need are not included in the Client Profile. This includes:
If you are building Server apps, Such as:
ASP.Net apps
Server-side ASMX based web services
If you use legacy client scenarios, Such as:
o Use System.Data.OracleClient.dll which is deprecated in NET4 and not included in the Client Profile.
Use legacy Windows Workflow
Foundation 3.0 or 3.5 (WF3.0 , WF3.5)
If you targeting developer scenarios and need tool such as MSBuild or need access to design assemblies such as System.Design.dll
Another thing that can cause this error is having NuGet packages that have been built with a newer version of .NET.
The original error:
frmTestPlanSelector.cs(11,7): error CS0246: The type or namespace name 'DatabaseManager'
could not be found (are you missing a using directive or an assembly reference?)
Further up in the log I found this:
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(1605,5): warning MSB3275: The primary reference "[redacted]\DatabaseManager\bin\Release\DatabaseManager.dll" could not be resolved because it has an indirect dependency on the assembly "System.Data.SQLite, Version=1.0.94.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139" which was built against the ".NETFramework,Version=v4.5" framework. This is a higher version than the currently targeted framework ".NETFramework,Version=v4.0".
The solution was to re-install the NuGet packages:
http://docs.nuget.org/docs/workflows/reinstalling-packages
I solved mine because the other project was coded with .NET 4.5 and the other one was coded 4.0
The using statement refers to a namespace, not a project.
Make sure that you have the appropriately named namespace in your referenced project:
namespace PrjTest
{
public class Foo
{
// etc...
}
}
Read more about namespaces on MSDN:
Using Namespaces
I encountered this issue it turned out to be.
Project B references Project A.
Project A compiled as A.dll (assembly name = A).
Project B compiled as A.dll (assembly name A).
Visual Studio 2010 wasn't catching this. Resharper was okay, but wouldn't compile. WinForms designer gave misleading error message saying likely resulting from incompatbile platform targets.
The solution, after a painful day, was to make sure assemblies don't have same name.
It is also possible, that the referenced projects targets .NET 4.0, while the Console App Project targets .NET 4.0 Client Library.
While it might not have been related to this particular case, I think someone else can find this information useful.
The compiled dll should have public Class.
I had the same issue. The target frameworks were fine for me. Still it was not working.
I installed VS2010 sp1, and did a "Rebuild" on the PrjTest. Then it started working for me.
Other problem that might be causing such behavior are build configurations.
I had two projects with configurations set to be built to specific folders.
Like Debug and Any CPU and in second it was Debug and x86.
What I did I went to Solution->Context menu->Properties->Configuration properties->Configuration and I set all my projects to use same configurations Debug and x86 and also checked Build tick mark.
Then projects started to build correctly and were able to see namespaces.
Changing the framework to
.NET Framework 4 Client Profile
did the job for me.
For COM/ActiveX references, VS 2012 will show this error right on using statement. Which is quite funny, since it's saying that may be you are missing a using statement.
To solve this: register the actual COM/ActiveX dll even if it's in the neighbor project, and add a reference through COM channel, not project channel. It will add Interop.ProjectName instead of ProjectName as a reference and this solves this strange bug.
If your project (PrjTest) does not expose any public types within the PrjTest namespace, it will cause that error.
Does the project (PrjTest) include any classes or types in the "PrjTest" namespace which are public?
just changed Application's target framework to ".Net Framework 4".
And error got Disappeared.
good luck;
:D
check your Project Properties, your Reference Paths should be empty like this:
Regards