Example with Possible NHibernate Implementation

AuditAttribute.cs

public class AuditAttribute : ActionFilterAttribute
{
     public override void OnActionExecuting(ActionExecutingContext filterContext)
     {
          //Stores the Request in an Accessible object
          var request = filterContext.HttpContext.Request;
          //Generate an audit
          Audit audit = new Audit()
          {
               //Your Audit Identifier     
               AuditID = Guid.NewGuid(),
               //Our Username (if available)
               UserName = (request.IsAuthenticated) ? 
                          filterContext.HttpContext.User.Identity.Name : "Anonymous",
               //The IP Address of the Request
               IPAddress = request.ServerVariables["HTTP_X_FORWARDED_FOR"] ?? request.UserHostAddress,
               //The URL that was accessed
               AreaAccessed = request.RawUrl,
               //Creates our Timestamp
               TimeAccessed = DateTime.UtcNow
          };

          // Create your NHibernate session / repository here and 
          // save your audit object

          //Finishes executing the Action as normal 
          base.OnActionExecuting(filterContext);
     }
}

@rionmonster Hey thanks so much for this, it worked, the info is stored into the db.
But now im having a problem to present the actual information from the db table to the view.

i am trying to show it with a list view.

@model IEnumerable<Dominio.Entidades.Audit>

@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>


<table class="table">
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.UserName)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.IPAddress)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.AreaAccessed)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Timestamp)
        </th>
        <th></th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.UserName)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.IPAddress)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.AreaAccessed)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Timestamp)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id=item.AuditID }) |
            @Html.ActionLink("Details", "Details", new { id=item.AuditID }) |
            @Html.ActionLink("Delete", "Delete", new { id=item.AuditID })
        </td>
    </tr>
}

</table>
`

But it is giving me an exception that the model is null.
I made the audit class and mapped it with NH and the model im bringing it from that audit class.

@rionmonster nevermind i solved that problem, but sadly im now stuck on the second part(advanced audit) part of your project.
Im stuck at
var sessionIdentifier = string.Join("", MD5.Create().ComputeHash(Encoding.ASCII.GetBytes(request.Cookies[FormsAuthentication.FormsCookieName].Value)).Select(s => s.ToString("x2")));
Where it always gives me the exception:
Object reference not set to an instance of an object

Any ideas please?