Programmatically get the version number of a DLL

This works if the dll is .net or Win32. Reflection methods only work if the dll is .net. Also, if you use reflection, you have the overhead of loading the whole dll into memory. The below method does not load the assembly into memory.

// Get the file version.
FileVersionInfo myFileVersionInfo = FileVersionInfo.GetVersionInfo(@"C:\MyAssembly.dll");

// Print the file name and version number.
Console.WriteLine("File: " + myFileVersionInfo.FileDescription + '\n' +
                  "Version number: " + myFileVersionInfo.FileVersion);

From: http://msdn.microsoft.com/en-us/library/system.diagnostics.fileversioninfo.fileversion.aspx

original source

Assembly assembly = Assembly.LoadFrom("MyAssembly.dll");
Version ver = assembly.GetName().Version;

Important: It should be noted that this is not the best answer to the original question. Don't forget to read more on this page.