Question

In my C# software, I have a number of drawing tools. Each tool has its own class with a common interface. E.g. “Draw rectangle”.

Now, many of these tools need to read data from my main window in order to perform their tasks. However, I don’t want these tools to be coupled with my MainForm class. Obviously, there is a need for a better design. Which design pattern is suitable for the task?

Q: How can class X read arbitrary information from class Y, without coupling the two classes?

Answer 1

You want to abstract Y into an interface designed specifically just to allow retrieving the kind of information X needs.

At the same time, you don’t want to leak into the interface the specifics of a particular implementation you may have in mind (for example your main window).