c# - Why must I chain reference assemblies?

Question

My project references an assembly (will call it X) that references another assembly (will call it Y).

When I try to compile my project, it demands that it should reference assembly Y. Why is that? I get the following error on the line where assembly X is referenced:

The type 'DevExpress.XtraEditors.XtraForm' is defined in an assembly that is not referenced. You must add a reference to assembly 'DevExpress.Utils.v9.1, Version=9.1.2.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a'.

DevExpress.XtraEditors.XtraForm is the assembly Y.

Why is this? I have not seen this behavior before.

Answer 1

This has always been in place. You will only get these at compile time if you're using an object that gets methods/properties/members etc from assembly Y.

The why is because .NET cannot rely on assembly X to ensure it will be able to obtain proper symbol and meta data information.