fingerprinter.cs

public static class Extensions
{
	public static string GetFingerPrint(this UrlHelper helper)
	{
		byte[] hash = SHA256.Create().ComputeHash(Encoding.Unicode.GetBytes(GetLastWriteTime()));
		return HttpServerUtility.UrlTokenEncode(hash);
	}
	
	/// <summary>
	/// 
	/// </summary>
	/// <returns></returns>
	public static string GetLastWriteTime()
	{
		string binFolder = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "bin");
		return new DirectoryInfo(binFolder).LastWriteTime.ToString();
	}
}

// Example usage in an MVC view:
<link type="text/css" href="~/Content/test.less?v=@Url.GetFingerPrint()" rel="stylesheet"/>