To complete the answer OD, NDepend - is a tool specifically designed for the analysis and management of large databases, .NET (legacy or not)).
The tool offers a quick analysis, graph and matrix of dependencies, code comparison, code management, full integration of VS and additional functions . You can try it now on your code as a free trial version .
Because you think that you are particularly interested in the study of addictions such as class associations, here - an introduction to start with the plot of. 
Here - an introduction to start with a matrix of dependencies (best suited for the analysis of dependencies in a large part of the code). 
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