I'm creating an app in which I want to utilise Xamarin.Forms' haptic feedback feature. This feature is currently under preview - so I went to the Microsoft documentation and got it setup as expected.
First of all - in my AssemblyInfo.cs in my Android project I added the following code:
[assembly: UsesPermission(Android.Manifest.Permission.Vibrate)]
Then I pasted in the following code from Microsoft into my code-behind:
HapticFeedback.Perform(HapticFeedbackType.Click);
After adding the code I get the following message:
Steps to reproduce
Open up a new project and under the Android AssemblyInfo.cs add the following code:
[assembly: UsesPermission(Android.Manifest.Permission.Vibrate)]
Paste in the following code: HapticFeedback.Perform(HapticFeedbackType.Click);
Now you should notice that intellisense says that HapticFeedback does not exist in the current context.
Things I've tried
I tried to update Xamarin.Forms and Xamarin.Essentials - but it still was not recognised for some reason
I tried to close and reopen the solution - but it sitll was not recognised.
I am looking for a solution to this so I can use haptic feedback in my application.
Image
The Xamarin.Essentials: Haptic Feedback is only available in Xamarin.Essentials pre-release version now.
To get pre-release version, check the include prerelease in the right corner:
Then you can use HapticFeedback in your project.
I'm trying to maintain an application that contains the following line in several different files:
using Microsoft.AspNet.Membership.OpenAuth;
I've tried everything I could find. Removed and re-added the reference; cleared the MEF cache and rebuilt; added a different file as a reference. Nothing works. It's bizarre because VS2017 doesn't report this error in the Error List window, but it does show up in the Output window. Anyway, can someone please suggest a possible solution that maybe I haven't tried yet? Thanks.
I was able to compile the project and I will describe how I got it.
1 - I delete all using Microsoft.AspNet.Membership.OpenAuth; and build project.
2 - After build the code show many errors I use the resource of VS2015 help fixes errors on code Show potential fixes and set again using Microsoft.AspNet.Membership.OpenAuth; build project.
3 - Set a new framework 4.6 and build project.
https://drive.google.com/open?id=0B4aywYtmwk6lT1dDNnIxRmtQcUk
Actually i want to use solver in my C# application. To add it as reference i downloaded and installed solver dll download in this site .
Then in my project i selected
Add->Reference->Browse->MicrosoftSolverFoundationForExcel.dll .
Now if i try to use using Microsoft.SolverFoundation.Common;
and using Microsoft.SolverFoundation.Services; , it is giving error while compiling. But if i use using Microsoft.SolverFoundation it is not giving any errors. Please guide me how to add these missing dll's.
After a long struggle I found the answer. Just go to Add reference->Assemblies->Framework->Microsoft Solver Foundation - Express Edition and check the check box. Thats it!
Thank you for reading my question.
I am updating a third-party library. My goal is to add a new control.
I seem to have added a new class to the namespace containing the group of controls, which I am trying to extend.
However, when I try to link again my "now extended" library, I don't see my new control.
Where does Xamarin Studio get the information regarding the classes contained inside a resource DLL? Is it from an mdb file?
Also, when I compile my library, DLL is created fine and mdb is not created. Is this OK?
Please advise.
Thank you
While I could not figure out how to find out from Xamarin Studio where is each/in-question listed library located on the disk, edit references menu has an option to specify the location from which the newly referenced assembly is loaded. This worked.
Thanks.
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.