How ASP.NET MVC Works

There are 100 monkeys in the valley below, and you are the general of the tigers. In any given attack, 75% of the tigers you send will catch and eat a monkey. How many would you like to send?

This is how many monkeys the tigers killed:

Discussion

I would put a lot of discussion into this sample, but that was done elsewhere. So if you want discussion, go see the Getting Started tutorial on creating a basic form.

The View

The following is what you have in the markup for the view:

    
There are 100 monkeys in the valley below, and you are the general of the tigers. In any given attack, 75% of the tigers
    you send will catch and eat a monkey. How many would you like to send?
       
    < %= Html.ValidationSummary() %>

    < % using (Html.BeginForm())
       { %>
       
       

                

                    Number of Tigers Sent:
                    < %= Html.TextBox("NumberOfTigersSent") %>
                    < %= Html.ValidationMessage("NumberOfTigersSent", "*") %>
                
       
       
          
    < % } %>

    
This is how many monkeys the tigers killed: < %= ViewData["NumberOfMonkeysEaten"]%>

    

Controller

The code for doing the calculations and the validation in the controller is as follows:

        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult TigersAssaultTheMonkeys(int? numberOfTigersSent)
        {
            int numberOfMonkeysEaten = 0;

            if (numberOfTigersSent.HasValue)
            {
                double numberOfPotentialMonkeysEaten = numberOfTigersSent.Value * .75;
                if (numberOfPotentialMonkeysEaten > 100)
                {
                    numberOfMonkeysEaten = 100;
                }
                else if (numberOfPotentialMonkeysEaten > 0)
                {
                    numberOfMonkeysEaten = Convert.ToInt32(Math.Round(numberOfPotentialMonkeysEaten, 0));
                }
            }
            else
            {
                ViewData.ModelState.AddModelError("NumberOfTigersSent", "Yo, whassup with that tiger count value?");
            }

            ViewData["NumberOfMonkeysEaten"] = numberOfMonkeysEaten;

            return View();
        }