Suppose that you have two dlls (ClassLibrary1.dll and
ClassLibrary2.dll).

Now suppose that both dlls have the same class declared on them using
the exact same name space and class name, for example, supposed both
dlls have the following snippet of code:

namespace SomeNameSpace
{
public class Class1
{
}
}

Now supposed you reference both dlls into your main project and add
the following snippet of code into this main project.

SomeNameSpace.Class1 cls = new SomeNameSpace.Class1();

If you try to compile the project you will get an error message
stating that “SomeNameSpace.Class1()” exist in both dlls and so the
compiler can’t choose which one to select.

Is there a way to specify what dll to use when instantiating Class1?

Thank you.

On Jun 23, 3:28*pm, qglyirnyf...@mailinator.com wrote:
> Suppose that you have two dlls (ClassLibrary1.dll and
> ClassLibrary2.dll).
>
> Now suppose that both dlls have the same class declared on them using
> the exact same name space and class name, for example, supposed both
> dlls have the following snippet of code:
>
> namespace SomeNameSpace
> {
> * * public class Class1
> * * {
> * * }
>
> }
>
> Now supposed you reference both dlls into your main project and add
> the following snippet of code into this main project.
>
> SomeNameSpace.Class1 cls = new SomeNameSpace.Class1();
>
> If you try to compile the project you will get an error message
> stating that “SomeNameSpace.Class1()” exist in both dlls and so the
> compiler can’t choose which one to select.
>
> Is there a way to specify what dll to use when instantiating Class1?

Yes, assuming you're using C# 2 or later. You need to use a feature
called "extern aliases" - that should be enough to get you going with
a good search. However, I'd stress that if you can *possibly* avoid
this, do so.

Jon

"extern alias":

http://msdn.microsoft.com/en-us/library/ms173212.aspx
http://blogs.msdn.com/ansonh/archive...27/774692.aspx

Marc

I have to agree with Jon, you should avoid reusing the same namespace and
type name repeatedly.

"Jon Skeet [C# MVP]" <(E-Mail Removed)> wrote in message
news:05badf78-c79a-465b-bf38-(E-Mail Removed)...
On Jun 23, 3:28 pm, qglyirnyf...@mailinator.com wrote:
> Suppose that you have two dlls (ClassLibrary1.dll and
> ClassLibrary2.dll).
>
> Now suppose that both dlls have the same class declared on them using
> the exact same name space and class name, for example, supposed both
> dlls have the following snippet of code:
>
> namespace SomeNameSpace
> {
> public class Class1
> {
> }
>
> }
>
> Now supposed you reference both dlls into your main project and add
> the following snippet of code into this main project.
>
> SomeNameSpace.Class1 cls = new SomeNameSpace.Class1();
>
> If you try to compile the project you will get an error message
> stating that “SomeNameSpace.Class1()” exist in both dlls and so the
> compiler can’t choose which one to select.
>
> Is there a way to specify what dll to use when instantiating Class1?

Yes, assuming you're using C# 2 or later. You need to use a feature
called "extern aliases" - that should be enough to get you going with
a good search. However, I'd stress that if you can *possibly* avoid
this, do so.

Jon