How to merge multiple assemblies into one?

You have several options:

• use ILMerge (free)
  For howto see here and here

OR

• use some tool like SmartAssembly (commercial)
  it can embed and merge among other things (no need to change your source code)

OR

• code that yourself in less than 10 lines (free but minimal source code change)
  mark all needed dependencies as "embedded resource" - this way they are included in the EXE file... you need to setup an AssemblyResolve handler which at runtime reads from Resources and returns the needed DLLs to the .NET runtime...

A great tool to include referenced assemblies as embedded resources is Costura (a Fody add-in). The author Simon Kropp describes it as follows:

[...] a combination of two methods:

• Jeffrey Richter's suggestion of using embedded resources as a method of merging assemblies
• Einar Egilsson's suggestion using cecil to create module initializers

The result is a super simple solution which merely requires to fetch Costura.Fody from NuGet.

Features:

• Including debug symbols
• Compression of embedded assemblies
• Including/excluding specific assemblies
• Others (see Readme)