< 1 min read The “OnActionExecuting” method is fired before every Action in a MVC controller. You can use this method to set and retrieve variables that are useful throughout your session, such as the person’s name, their profile photo, etc.
The following is an example implementation of this method

public class HomeController : Controller
{
    protected override void OnActionExecuting(ActionExecutingContext ctx)
    {
        base.OnActionExecuting(ctx);
        using (Repository rep = new Repository())
        {
            if (Request.IsAuthenticated)
            {
                var profile = rep.GetProfileByID((Guid)Membership.GetUser().ProviderUserKey);
                ViewBag.Name = profile.DisplayName;
            }
        }
    }
    public ActionResult Index()
    {
        //your code
        return View();
    }
    //rest of your methods
}

< 1 min read Enums can be very powerful when used appropriately, such as for populating fixed drop-down lists which almost never change

Let’s say you want to save a person’s gender in your database. You could save it as a string, but that’s very wasteful. Ideally you’d save it as tinyint, because it will never have more values, so why waste space and computing time with joins, or other solutions.
Your enum could look like this

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel;

namespace Data.Enums
{
    public enum Genders : byte
    {
        [DescriptionAttribute("No Answer")]
        NoAnswer = 0,
        [DescriptionAttribute("Male")]
        Male = 1,
        [DescriptionAttribute("Female")]
        Female = 2
    }
}

3 min read

void Application_Error(object sender, EventArgs e)
{
    ErrorTracking.TrackingInfo info = new ErrorTracking.TrackingInfo();
    info.ErrorPath = "http://" + Request.ServerVariables["HTTP_HOST"] + Request.Path;
    info.RawUrl = Request.RawUrl;
    string strError = "Error in: http://" + Request.ServerVariables["HTTP_HOST"] + Request.Path +
    "nUrl: " + Request.RawUrl + "nn";
    try
    {
        // Get the exception object for the last error message that occured.
        Exception ErrorInfo = Server.GetLastError().GetBaseException();
        if (ErrorInfo != null)
        {
            strError += "Error Message: " + ErrorInfo.Message +
                "nError Source: " + ErrorInfo.Source +
                "nError Target Site: " + ErrorInfo.TargetSite;
            info.ErrorMessage = ErrorInfo.Message;
        }
        strError += "Error Type: " + Server.GetLastError().GetType().ToString();
        info.ErrorType = Server.GetLastError().GetType().ToString();
        if (Server.GetLastError().GetType() == typeof(HttpUnhandledException))
        {
            strError += "Source: " + (Server.GetLastError() as HttpUnhandledException).GetHtmlErrorMessage();
            info.ErrorSource = (Server.GetLastError() as HttpUnhandledException).GetHtmlErrorMessage();
        }
        info.QueryStringData = "";
        strError += "nnQueryString Data:n-----------------n";
        // Gathering QueryString information
        for (int i = 0; i < Context.Request.QueryString.Count; i++)
        {
            strError += Context.Request.QueryString.Keys[i] + ":tt" + Context.Request.QueryString[i] + "n";
            info.QueryStringData += Context.Request.QueryString.Keys[i] + ":tt" + Context.Request.QueryString[i] + "n";
        }
        strError += "nPost Data:n----------n";
        info.PostData = "";
        // Gathering Post Data information
        for (int i = 0; i < Context.Request.Form.Count; i++)
        {
            strError += Context.Request.Form.Keys[i] + ":tt" + Context.Request.Form[i] + "n";
            info.PostData += Context.Request.Form.Keys[i] + ":tt" + Context.Request.Form[i] + "n";
        }
        strError += "nSession Data:n----------n";
        // Gathering Session information
        for (int i = 0; i < Context.Session.Count; i++)
        {
            strError += Context.Session.Keys[i] + ":tt" + Context.Session[i] + "n";
        }
        strError += "n";
        if (User.Identity.IsAuthenticated)
        {
            strError += "User:tt" + User.Identity.Name + "nn";
            info.UserAccountName = User.Identity.Name;
        }
        info.StackTrace = Server.GetLastError().StackTrace;
        strError += "Exception Stack Trace:n----------------------n" + Server.GetLastError().StackTrace +
            "nnServer Variables:n-----------------n";
        // Gathering Server Variables information
        info.ServerVariables = "";
        for (int i = 0; i < Context.Request.ServerVariables.Count; i++)
        {
            strError += Context.Request.ServerVariables.Keys[i] + ":tt" + Context.Request.ServerVariables[i] + "n";
            info.ServerVariables += Context.Request.ServerVariables.Keys[i] + ":tt" + Context.Request.ServerVariables[i] + "n";
        }
        strError += "n";
    }
    catch (Exception s) { strError += s.Message; }
    info.CompleteSource = strError;
    info.SiteKey = Guid.Parse(System.Configuration.ConfigurationManager.AppSettings["ErrorTrackingKey"]);
    info.IsRead = false;
    info.IsResolved = false;
    info.DateLogged = DateTime.Now;
    info.ErrorCause = ErrorTracking.ErrorCauses.Unknown;
    info.UserAccountID = Guid.Empty;
    info.ErrorSource = "";
    info.UserAccountName = "";
    ErrorTracking.ErrorTrackingServiceClient client = new ErrorTracking.ErrorTrackingServiceClient();
    client.SubmitError(info);
    // Send email to developer
    System.Net.Mail.MailMessage m = new System.Net.Mail.MailMessage();
    m.To.Add(System.Configuration.ConfigurationManager.AppSettings["DebugEmail"]);
    m.Subject = "Error occurred on " + Request.ServerVariables["HTTP_HOST"];
    m.IsBodyHtml = false;
    m.Body = strError;
    System.Net.Mail.SmtpClient c = new System.Net.Mail.SmtpClient();
    try
    {
        c.Send(m);
    }
    catch { }
}

< 1 min read Let’s take a look at a brand new MVC 3 validator – RemoteAttribute. The Remote validator is very simple to use and yet extremely powerful. Remote is for situations where it is impossible to duplicate server side validation logic on the client, often because the validation involves connecting to a database or calling a service. If all your other validation uses javascript and responds to the user’s input immediately, then it is not a good user experience to require a post back to validate one particular field. This is where the remote validator fits in.
In this example, we are going to add remote validation to the username field to check that it is unique.

[Remote("ValidateUserName", "Account", ErrorMessage = "Username is not available.")]
public string UserName { get; set; }

Remote has three constructors allowing you to specify either a routeName, a controller and action or a controller, action and area. Here we are passing controller and action and additionally overriding the error message

public ActionResult ValidateUserName(string username)
{
    return Json(!username.Equals("duplicate"), JsonRequestBehavior.AllowGet);
}