You could use a function like this:

    public static Version GetExecutingAssemblyVersion()
    {
        var ver = FileVersionInfo.GetVersionInfo(Assembly.GetExecutingAssembly().Location);

        // read what's defined in [assembly: AssemblyFileVersion("1.2.3.4")]
        return new Version(ver.ProductMajorPart, ver.ProductMinorPart, ver.ProductBuildPart, ver.ProductPrivatePart);
    }