Using TempData Outside the Controller in ASP.NET MVC

rtp4, 2 Jun 2014

4.86 (3 votes)

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Using TempData outside the controller in ASP.NET MVC and making TempData less prone to error and more intuitive.

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What is the Problem We Are Trying to Fix?

When you start using Tempdata, it quickly becomes evident that maintaining it will be quite a challenge because Intellisense doesn't support Tempdata since it's a Dictionary. Without intellisense, suddenly life looks gloomy, but no fear. There is hope!

My Problem

The problem raised when I wanted to use Notification Object across my website. I wanted to throw this object from one controller to the other (tempdata job) and finally send it to the view. If I wanted to useTempData["something"], then I have to remember this "something".
So instead of hardcoding this "something" inside the controller, I decided to put the hardcoding inside aHelper.cs function and simply call intuitive functions that will Get/Set/Remove the object. The beauty of it is that - there is Intellisense to help us out!

Solution

The solution is quite simple.

1. Create the Notification object
2. Create a helper function that will do the dirty work (get;set;remove)

Since we moved TempData outside the controller, we are obliged to send the controller to be able to use theTempData. We send the controller by the keyword this.

PromptNotification.cs

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public class PromptNotification //Notification Object
{
    public bool NotificationSuccess { get; set; }
    public string NotificationMessage { get; set; }
}

Helper.cs

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public static void SetPromptNotification(Controller controller, bool success,string message)
{
    PromptNotification promptNotification = new PromptNotification
    {
        NotificationSuccess = success,
        NotificationMessage = message
    };
    controller.TempData["PromptNotification"] = promptNotification;
}

public static PromptNotification GetPromptNotification(Controller controller)
{
    try
    {
        PromptNotification promptNotification = controller.TempData["PromptNotification"] 
            as PromptNotification;
        return promptNotification;
     }
     catch (Exception ex)
     {
         // log error here

         return null;
     }
}

public static void RemovePromptNotification(Controller controller)
{
    controller.TempData.Remove("PromptNotification");
}

UserController.cs //set

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// add promp message => redirect to index
Helper.SetPromptNotification(this, true, 
    "You will shortly receive an email, please verify your registration.");

MainController.cs //get

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// get promptnotification => if it exist => pass it to the view => clear the notification
PromptNotification promptNotification = Helper.GetPromptNotification(this);

if (promptNotification != null)
{
    ViewBag.NotificationSuccess = promptNotification.NotificationSuccess;
    ViewBag.NotificationMessage = promptNotification.NotificationMessage;

    Helper.RemovePromptNotification(this);
}

Index.cshtml

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@if (ViewBag.NotificationSuccess != null)
{
    PromptNotification promptNotification = new PromptNotification
    {
        NotificationSuccess = (bool)ViewBag.NotificationSuccess,
        NotificationMessage = ViewBag.NotificationMessage as string
    };
    
    string notificationClassName = String.Empty;

    if (promptNotification.NotificationSuccess == true)
    {
        notificationClassName = "notificationSuccessWrapper";
    }
    else
    {
        notificationClassName = "notificationErrorWrapper";
    }
    
    <div class="@Html.Raw(notificationClassName)">
        @promptNotification.NotificationMessage
    </div>
}