.NET assembly dependency analyser

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After manually drawing an assembly dependency graph for a twenty-something project solution, I tackled the task of doing this in software. The application I wrote is available here for public use. Hopefully if people people make modifications, they'll send them to me.

Run the application, and open a .NET assembly from the File|Open menu (or just press CTRL+O). The analyser will immediately generate a diagram such as the one shown.

Example screenshot from .NET Assembly Dependency Analyser chart.

Most assemblies will reference large numbers of system assemblies, either directly or indirectly. In this graph, both the System and mscorlib assemblies are referenced by almost all other assemblies. The diagram is clearer without these explicit references.

See this graph, exported as a PNG file.

Example of the exclude menu showing how to omit selected assemblies from the chart.

Check any assemblies that don't add any value to the graph. Once this is done, refresh the plot either via the View menu, or by pressing F5.

A chart showing dependencies when most of the behind-the-scenes assemblies have been removed.

This plot tells us a great deal about the analysed assembly (in this case, Drew.Controls.Map.dll). It requires 3 non-system assemblies: Drew.Types, Drew.Util and nunit.framework, even though nunit.framework is no referenced directly. We can also tell, unsurprisingly, that Drew.Controls.Map uses WinForms assemblies.

Note the circular dependency between System and System.Xml!!!

Excluding all System assemblies shows all dependent assemblies that must be deployed with the selected assembly for it to operate properly.

A chart showing uncluttered core dependencies when all framework and other supporting assemblies have been removed.

Here's an example of the SVG output.

The graph

The graph is produced via a Dot script. WinGraphViz is a COM component that generates Dot images, and is used by this application. It must be installed for the .NET dependency analyser to work.

A Dot script may look something like this:

digraph G { size="100,69" center="" ratio=All node[width=.25,hight=.375,fontsize=12,color=lightblue2,style=filled] 1 -> 9; 1 -> 11; 9 -> 10; 11 -> 10; 1 [label="Drew.Controls.Map"]; 9 [label="Drew.Types"]; 10 [label="nunit.framework"]; 11 [label="Drew.Util"]; }

This markup can be seen in the 'Dot Output' tab.

More information on Dot can be found at http://www.graphviz.org/

Installing the dependency analyser

dot-net-dependency-analyser-1.0-release.zip (362KB) - Binaries (no source) including WinGraphViz installer

dot-net-dependency-analyser-1.0-source.zip (43KB) - Full source code (no binaries or WingraphViz installer) - Solution uses VS.NET 2003

WinGraphviz_v1.02.17.msi (389KB) - The WingraphViz installer (required to run the dependency analyser)

TODO list

compare references as dictated by compiler, versus those specified in projects/solution
support sln files for newer versions of visual studio
remember user's preferences for exclusion
support merging of multiple solution files
allow multiple select in Open dialog
allow printing of the image
use colouring/shapes on graph
- indicate assemblies loaded from GAC, and those loaded from root directory
- colour for those with more/less/no dependencies/dependents
show number of dependents/dependencies in exclusion list
menu items to show/hide all System.*
colour coding for nodes using wildcards (e.g. System.* = blue)