[assembly: AssemblyDelaySign(false)]
[assembly: AssemblyKeyFile("..\\..\\ActiveDateTime.key")]
[assembly: AssemblyKeyName("")]

[assembly: AssemblyKeyFile("..\\..\\ActiveDateTime.key")]
needs to be updated.

------ Rebuild All started: Project: ActiveDateTime, Configuration: Debug Any CPU ------
C:\Windows\Microsoft.NET\Framework\v3.5\Csc.exe /noconfig /nowarn:1701,1702 /errorreport:prompt /warn:4 /define:DEBUG;TRACE /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.DataSetExtensions.dll" /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Drawing.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Web.dll /reference:C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll" /debug+ /debug:full /filealign:512 /optimize- /out:obj\Debug\ActiveDateTime.dll /target:library ActiveDateTime.cs DateChangedEventArgs.cs Properties\AssemblyInfo.cs
C:\inetpub\wwwroot\OmegaLove_CS\OL_DateTimePicker\ActiveDateTime\ActiveDateTime\Properties\AssemblyInfo.cs(76,12): warning CS1699: Use command line option '/keyfile' or appropriate project settings instead of 'AssemblyKeyFile'

Compile complete -- 0 errors, 1 warnings
ActiveDateTime -> C:\inetpub\wwwroot\OmegaLove_CS\OL_DateTimePicker\ActiveDateTime\ActiveDateTime\bin\Debug\ActiveDateTime.dll
========== Rebuild All: 1 succeeded, 0 failed, 0 skipped ==========
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

From doc:
In order to sign an assembly, it is necessary to specify a key file. Prior to Microsoft Visual C# 2005, you specified the key file using CLR attributes in source code. THESE ATTRIBUTES ARE NOW DEPRECATED.

Beginning in Microsoft Visual C# 2005, you should use the Signing Page of the Project Designer or the Assembly Linker to specify the key file.
Use http://msdn.microsoft.com/en-us/library/w2kyay38.aspx instead of the AssemblyKeyFileAttribute attribute.
mathieu_cuprykAuthor Commented:
is it necessary to sign an assembly?
If you want to register some dll into a GAC for example. You need to register an assembly into the GAC (and then it's mandatory that your assembly has a string name) if your assembly is supposed to be shared by several application for example... However it depends on what you are doing with your assembly. Do you need to deploy it on customer machines in the context where your company sells a software ?
An assembly is identified by its text name, version number and culture info. However, these pieces of info will not guarantee that an assembly will be unique. There might be cases in which 2 soft publishers end up using the same identity and lead to some strnge behaviours on the targetted machines. You greatly reduce such issues by giving strong names to your assemblies. A strong name strengthens an assembly's identity by qualifying it with the sofware identity. .Net framework uses a standard crypto technique known as digital signing.
Signing is also usefull when you want to be sure that your assembly has not been tampered.
Let's have a look : http://www.csharp411.com/net-assembly-faq-part-3-strong-names-and-signing
CompTIA Cloud+

The CompTIA Cloud+ Basic training course will teach you about cloud concepts and models, data storage, networking, and network infrastructure.

mathieu_cuprykAuthor Commented:
The assembly should be signed?
mathieu_cuprykAuthor Commented:
when and when not to sign an assembly?
I don't understand your questions since I provided an explanation about what the signature is for. Moreover the link I proposed go further deeper in this explanation.
So the only one who can answer your questions is yourself since you know what you need.
mathieu_cuprykAuthor Commented:
I think it is important to go with signing the assemblies.
OK, so let's go for signing... Then, where is the issue now ?

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.