[Mono-dev] Compiling a C# project with Xamarin Studio + MonoRuntime does not work.

Vardar Sahin sakirsoft at gmail.com
Mon Apr 21 10:29:34 UTC 2014

I was able to create a little test case. In the attachment you can find the
test solution.
You have to switch your .Net run time in XamarinStudio to Mono to see the

When you try to compile it with Visual Studio or with the .Net runtime it
will compile just fine.

2014-04-21 12:11 GMT+02:00 Vardar Sahin <sakirsoft at gmail.com>:

> Thanks for that hint but I do not see some thing like this in my project.
> 2014-04-20 18:49 GMT+02:00 Mackey Kinard <Mackey at ehsiplus.com>:
> Your cs1685 error is because your are duplicating the definition of the
>> compiler services class.
>> This mainly happens when you are making extension to classes. If your are
>> targeting .net
>> 3.5 or higher the extension attribute is define in mono... In previous
>> versions ... Like .net
>> 2.0 you had to define the attribute yourself...
>> So probably when you made library of code that required you to define
>> extension attribute that
>> Was .net 2.0... But you are using that library in a .net 3.5 or greater
>> project which already has
>> Extention attribute defined...
>> I usually make a separate dll with the extension attribute as the only
>> class... Then in my .net
>> 2.0 projects (that I keep 2.0 to maintain compatible usage of my library
>> for all versions) I reference this dll with the extension attribute...
>> Otherwise, no need to define the extension attribute at all (for new .net
>> projects)
>> Sent from my iPad
>> On Apr 20, 2014, at 6:23 AM, Vardar Sahin <sakirsoft at gmail.com> wrote:
>> Hi Guys,
>> I have a C# project which compiles just fine with Visual Studio. It also
>> compiles when I use Xamarin Studio and the .Net runtime. But when I choose
>> to use the MonoRuntime it does not compile anymore.
>> I am using the current version of Xamarin Studio ( 4.2.3 ). Interesting
>> is that when I use an older Version of Xamarin Studio ( 4.1.9 ) +
>> MonoRuntime it works.
>> I am on Windows and use the latest stable version of mono ( 3.2.3 ).
>> The compiler error I get is the following.
>> *Error CS0433: The imported type `System.Action<T1,T2>' is defined
>> multiple times (CS0433) *
>>  Also I have a Warning like this
>> *Warning CS1685: The predefined type
>> `System.Runtime.CompilerServices.ExtensionAttribute' is defined multiple
>> times. Using definition from `mscorlib.dll' (CS1685) *
>> The signature of the function where the error occurs is this.
>> *private void ApplyCollision(ulong goId, CollisionData data,
>> Action<ICollisionListener, Collision> func)*
>> Any ideas how to fix this?
>> Best
>> Sahin
>> _______________________________________________
>> Mono-devel-list mailing list
>> Mono-devel-list at lists.ximian.com
>> http://lists.ximian.com/mailman/listinfo/mono-devel-list
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