I cannot seem to find the JavaScriptSerializer object nor the the System.Web.Script.Serialization namespace within Visual Studio 2010. I need to serialize something to JSON what am I supposed to use?
And yes, I already included the System.Web.Extensions (in System.Web.Extensions.dll) within the project. Which is why I am shocked?
I do know System.Web.Extensions was marked as obsolete in 3.5
Check if you included the .net 4 version of System.Web.Extensions - there's a 3.5 version as well, but I don't think that one works.
These steps work for me:
Create a new console application
Change the target to .net 4 instead of Client Profile
Add a reference to System.Web.Extensions (4.0)
Have access to JavaScriptSerializer in Program.cs now :-)
Right click References and do Add Reference, then from Assemblies->Framework select System.Web.Extensions.
Now you should be able to add the following to your class file:
using System.Web.Script.Serialization;
From the first search result on google:
http://msdn.microsoft.com/en-us/library/system.web.script.serialization.javascriptserializer.aspx
JavaScriptSerializer Class
Provides serialization and deserialization functionality for AJAX-enabled applications.
Inheritance Hierarchy
System.Object
System.Web.Script.Serialization.JavaScriptSerializer
Namespace: System.Web.Script.Serialization
Assembly: System.Web.Extensions (in System.Web.Extensions.dll)
So, include System.Web.Extensions.dll as a reference.
I'm using Visual Studio 2015 and finally ran across this post.
Yes in order to use
JavaScriptSerializer json = new JavaScriptSerializer();
You must right click on references and under Assemblies --> Framework choose
System.Web.Extensions
Then add in your reference
using System.Web.Script.Serialization;
This is how to get JavaScriptSerializer available in your application, targetting .NET 4.0 (full)
using System.Web.Script.Serialization;
This should allow you to create a new JavaScriptSerializer object!
using System.Web.Script.Serialization;
is in assembly : System.Web.Extensions (System.Web.Extensions.dll)
Are you targeting the .NET 4 framework or the .NET 4 Client Profile?
If you're targeting the latter, you won't find that class. You also may be missing a reference, likely to an extensions dll.
For those who seem to be following the answers above but still have the problem (e.g., see the first comment on the poster's question):
You are probably working in a solution with many projects. The project you appear to be working in references other projects, but you are actually modifying a file from one of the other projects. For example:
project A references System.Web.Extensions
project A references project B
But if the file you are modifying to use System.Web.Script.Serialization is in project B, then you will need to add a reference to System.Web.Extension in project B as well.
Did you include a reference to System.Web.Extensions? If you click on your first link it says which assembly it's in.
You have to add the reference to the project.
In Assemblies, there is a System.Web.Extensions Add that.
Once that is done put:
using System.Web;
using System.Web.Script;
using System.Web.Script.Serialization;
That worked for me.
You can use another option which is the Newtonsoft.Json, you can install it from NuGet Package Manager.
Tools >> Nuget Package Manager >> Package Manager Console by issuing command
Install-Package Newtonsoft.Json
or
by using the GUI at Tools >> Nuget Package Manager >> Manage NuGet Packages for Solution...
Just so you know, I am using Visual Studio 2013 and have had the same problem until I used the Project Properties to switch to 3.5 framework and back to 4.5. This for some reason registered the .dll properly and I could use the System.Web.Extensions.
Related
I want to use an API to get info from the interwebz. The API returns data in Json format.
I'm running Microsoft Visual Studio C# 2010 Express addition.
It appears that I have the .NET Framework 4 Client Profile set as my
"Target framework" but I'm honestly not sure exactly what this
means.
This is a Windows Forms Application...
Not much code to show because I can't really get started without the appropriate using statement...
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Net;
using System.Runtime.Serialization.Json;
I get this error:
The type or namespace name 'Json' does not exist in the namespace
'System.Runtime.Serialization' (are you missing an assembly
reference?)
Am I missing a DLL file or something? Based on my hours of fruitlessly searching for solutions, I understand that the .NET 4.xx should already have the tools needed to parse up a Json formatted string?
The System.Runtime.Serialization.Json Namespace is in two different DLL's depending on your .net framework.
In .NET 3.5 It is in System.ServiceModel.Web.dll
In .NET 4.0 and above It is in System.Runtime.Serialization.dll.
Make sure you have added the correct DLL as a reference in your project and add using System.Runtime.Serialization.Json; to the top of your code file.
EDIT - Consider using JSON.NET
Even though the .NET Framework supplies its own JSON Serialization and Deserialization namespaces (DataContractJsonSerializer and JavaScriptSerializer) you should investigate whether you would be better off using JSON.NET.
JSON.NET is easier to use, better performance and has far more features.
http://www.newtonsoft.com/json/help/html/JsonNetVsDotNetSerializers.htm
you need to import System.Runtime.Serialization dll from reference
You need to add a reference to your project.
In the Solution Explorer right click references then add reference. You'll see a list of DLL's and you have to check the box next to the one you need for it to be added to the project. After you've done this you can successfully add the using statement.
Hope that helps!
The general process for serializing and deserializing JSON from C# is:
Add a reference to the System.Runtime.Serialization library.
Add using directives for System.Runtime.Serialization and System.Runtime.Serialization.Json.
Please change your Target framework from .NET Framework 4 Client Profile to .NET Framework 4
I know this is an old question, but I came across this in .NET 5.0 and the solution is to add using System.Text.Json to the top of your code.
I want to save this object:
Student s = new Student();
to Json file. But Visual Studio 2012 can't find none of these namespaces:
System.Web.Script;
System.Json;
System.Runtime.Serialization.Json;
Any idea?
If you want to serialize class into Json you can try this one too:
Install JSON.NET if you haven't yet.
make sure to include using Newtonsoft.Json;
and you can try this code:
Student s = new Student();
string json = JsonConvert.SerializeObject(s);
sorry for my bad english.
Step 1: Google "System.Runtime.Serialization.Json Namespace" and find this page:
System.Runtime.Serialization.Json Namespace
Step 2: Click on the class you are interested in ( let's say JsonReaderWriterFactory Class )
Step 3: Read the part that says what assembly that class is in:
Assembly: System.Runtime.Serialization (in
System.Runtime.Serialization.dll)
Step 4: Add that DLL as a reference to your project. See: How to: Add or Remove References By Using the Add Reference Dialog Box
Step 5: Repeat Steps 1 - 4 as needed.
Make sure you add the appropriate references to your project. For example, to use the datacontractjsonserializer class, you need to add a reference to System.Runtime.Serialization to your project.
If you're using visual studio, read How to: Add or Remove References in Visual Studio.
You can then use it with:
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(Student));
ser.WriteObject(outputStream, student);
Of course there are many other ways to do this and I won't go into detail about each one (I'm sure you've found some examples since you listed those namespaces).
TIP: if you want to use a .NET class and you're not sure what reference you need to add to your project in order to use it, open up the MSDN page for the class and look for the text like:
Assembly: System.Runtime.Serialization (in System.Runtime.Serialization.dll)
That's the assembly reference you need to add to your project.
The other answers are correct in saying that you need to add references to the appropriate assemblies. As an easy way to manage references for a personal project, I'd recommend NuGet, a package manager for Visual Studio. Thankfully, NuGet ships with Visual Studio 2012, so you just have to right-click the project, click on "Manage NuGet packages", and search for Json.NET. The first blog post I found on using NuGet in Visual Studio 2012 is here, and it seems to give a nice set of instructions, complete with screenshots.
You probably need to add references to your project:
System.Runtime.Serialization.Json is in System.Runtime.Serialization
System.Web.Script is in System.Web.Extensions
System.Json is only for Silverlight
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.
Why might "using System.Linq" cause the following error?
The type or namespace name 'Linq' does
not exist in the namespace 'System'
Reference System.Core
And then there are others that merge this namespace too - but that's the primary one on .Net 3.5 and above.
If you're project is currently .Net 2.0, say, and you're using the right version of VS (2005 and above) - you can simply right-click on the proejct properties; and change the 'Target Framework Version' to 3.5. System.Core will then become available.
If you don't see that in the options - then I guess you're using an older VS
The most probable reason is that you are using wrong version of .NET Framework.
Try to add System.Core assembly to your project
You'll get this error if you don't have "System.Core.dll" referenced (the assembly which contains the core LINQ APIs).
System.Linq is available in .Net 3.5 and above version.
Maybe you're targeting an older framework, Linq came in with 3.5 IIRC.
You are using lower version of .NET Framework than 3.5 to compile the source code or you don't have added the System.Core assembly to your project.
Manually type using System.Linq in the starting of the project, you will not be able to find this namespace in add reference dialogue box.
If you are still getting error then try to Add Reference System.Core.
If you are getting an error that it has been already referred then you can unload your project and then edit your csproject file, manually copy reference to System tag and paste and change the name to System.Core and reload the project.
In my case the only thing that worked was:
Adding a new Razor item (e.g. MVC 5 View Page)
That automatically pulls in some NuGet packages
The package that makes System.Linq available to Razor Views IntelliSense seems to be Microsoft.AspNet.WebPages.
I'm using Visual Studio 2010 and trying to use the BigInteger type in a C# program. This type is supposed to be available in System.Numerics namespace, but I don't seem to have that installed in the .Net 4.0 framework. When I type "using System.Numerics;" in VS2010, a red underline appears under the "Numerics". Has anyone else ever had this problem?
If so, how do you resolve it? I just re-downloaded and re-installed (repaired) the .Net 4.0 framework, but that didn't help. I've never had any problems with other C# programs that I've written, so I'm wondering what I'm missing.
You need to add an assembly reference to System.Numerics.dll
The MSDN entry on BigInteger states:
BigInteger Structure
...
Namespace: System.Numerics
Assembly: System.Numerics (in System.Numerics.dll)
Though most assemblies are the part of the installation, VS does add only some core elements to the reference list of a project (Core, Data, XML etc.). One needs to add other references by hand using Reference Manager.
Right-click your project, then select Add Reference (or Add->Reference). System.Numerics resides in Assemblies. Then you can use using System.Numerics; in project files.
PS: this answer is not intended to get any vote. It is only for future reference if someone needs how to do it, just as I needed before this answer.