Dynamic invocation and interfaces

[Chakravarthy Bollapalli \(IFIN SCC AI\)]

Hi,
I have a .net dll (say dll assembly) which has a class implimenting an
interface defined in a application (say application assembly)
so I add the reference of the application assembly to the dll project and
compile. I have a dll available.

from the application assembly i create an instance of the class defined in
dll assembly.

When i try to typecast the instance into an interface instance I get an
exception
--
An unhandled exception of type 'System.InvalidCastException' occurred in
test.exe

Additional information: Specified cast is not valid.
--

but I am able to invoke methods on the instance using
Type.InvokeMember(......) method.

what could be wrong?

kalyan

 

[Dmitriy Lapshin [C# / .NET MVP]]

Hi,

I'd declare the interface in the DLL instead. Referencing the application
assembly from a DLL is definitely not a good idea and it should be avoided.

--
Sincerely,
Dmitriy Lapshin [C# / .NET MVP]
Bring the power of unit testing to the VS .NET IDE today!
http://www.x-unity.net/teststudio.aspx

"Chakravarthy Bollapalli (IFIN SCC AI)"

 

[Chakravarthy Bollapalli \(IFIN SCC AI\)]

Hi,
May be its not a good idea to declare it in the application assembly but
my requirement is that I declare it in application assembly.
Infact there is one such example in oreilly's "Programming Visual C#
..NET 2003" chapter 18.

I am not sure what I am missing some compilation option or did visual
studio screw it up.

Anticipating a response

regards
kalyan

Hi,

I'd declare the interface in the DLL instead. Referencing the application
assembly from a DLL is definitely not a good idea and it should be avoided.

--
Sincerely,
Dmitriy Lapshin [C# / .NET MVP]
Bring the power of unit testing to the VS .NET IDE today!
http://www.x-unity.net/teststudio.aspx

"Chakravarthy Bollapalli (IFIN SCC AI)"

Hi,
I have a .net dll (say dll assembly) which has a class implimenting an
interface defined in a application (say application assembly)
so I add the reference of the application assembly to the dll project and
compile. I have a dll available.

from the application assembly i create an instance of the class defined in
dll assembly.

When i try to typecast the instance into an interface instance I get an
exception
--
An unhandled exception of type 'System.InvalidCastException' occurred in
test.exe

Additional information: Specified cast is not valid.
--

but I am able to invoke methods on the instance using
Type.InvokeMember(......) method.

what could be wrong?

kalyan

 

[Ravichandran J.V.]

When there is no relationship between types, you are not allowed to
typecast.

Try declaring the interface elsewhere and not in the application dll.

with regards,


J.V.Ravichandran
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