C# Class library cross reference not allowed?

[sathenzar]

Hey guys I want to build a DLL that can access all my forms properties and have the forms able to access the dll functions. Microsoft seemed to make

it impossible to do this. Any ideas? I can't add a reference of each other in both projects b/c of some error about how it's create circular speculation...that's what I want...both projects to be able to access both data.

[Antaris Veteran]

Circular referencing projects can be difficult because of the semenatics behind trying to compile them (which one would you compile first?), and load them. If the libraries will both be dependant on each other, would it not be easier to just compile them into the same project?

One way to get round them is to use an Event based mechanism, but it wouldn't be very pretty:

Project A declares Event 1

Project B creates a handler for Event 1

Project A fires Event 1

Project B catches Event 1

Only Project B is dependant on Project A

Create a custom event handler in Project A, which Project B implements but Project A fires. Make sense?

[sathenzar]

eh...not really. B/c how would I get project b to create a handle out of anything from project a if I can't include both?

I would love to put them in the same project but VS 2005 doesn't allow you to add a .dll file project into an existing Windows Form project.

Is there a link maybe to explain more of what you're talking about?

[SharpGreen]

Visual Studio 2005 allows both kinds of projects to be in the same solution. The way antaris described it the 2 projects won't need to include each other. Only Project B would need to include Project A.

[azcodemonkey]

Honestly, this doesn't sound like a good design. You can work around this, though.

My first thought, and I didn't get much sleep so forgive if I'm not clear, is to create a base class or interface that your forms implement inside another DLL. This base should include all the properties you want to expose to the primary DLL. Have your primary DLL reference this abstract type instead of the concrete type. Your Win form project should reference this, too, of course. Now your primary dll can be reference by your Win form app and your win form app can pass in the base type to your primary dll. You've created a triangular reference instead of a circular one. ;)

You should really rethink your design, though. If that much data and functionality really needs to be shared between 2 classes, it should be one class or a hierarchy.

[Antaris Veteran]

Ah, the Seperate Interface pattern, never thought of that.

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You should really rethink your design, though. If that much data and functionality really needs to be shared between 2 classes, it should be one class or a hierarchy

Yeah, thats what I meant when I said

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If the libraries will both be dependant on each other, would it not be easier to just compile them into the same project?

Also,

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I would love to put them in the same project but VS 2005 doesn't allow you to add a .dll file project into an existing Windows Form project

When you click File..Open or File..New, the dialog gives you the option of either creating a new solution, OR, adding the project to the existing solution.