ASP.NET TempData

last modified April 3, 2025

In this article, we explore TempData in ASP.NET 8. TempData is a dictionary object used to pass data between controllers and views during redirects.

ASP.NET is a cross-platform, high-performance framework for building modern web applications. TempData provides a simple way to maintain state between requests.

Basic Definition

TempData is a property of ControllerBase class in ASP.NET. It stores data temporarily between two consecutive requests. The data is available only until it's read or the request completes.

TempData uses session state behind the scenes but is specifically designed for redirect scenarios. It's commonly used to pass messages or small data between actions during a redirect.

Unlike ViewData and ViewBag, TempData persists for an additional request. It's implemented using either cookies or session state, depending on configuration.

ASP.NET TempData Example

The following example demonstrates using TempData to pass a success message between actions during a form submission and redirect.

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllersWithViews();
builder.Services.AddSession(); // Required for TempData

var app = builder.Build();

app.UseSession(); // Required for TempData
app.MapControllers();
app.MapDefaultControllerRoute();
app.Run();

This sets up a basic ASP.NET MVC application with session support. The AddSession and UseSession calls are required for TempData to work properly.

using Microsoft.AspNetCore.Mvc;

public class ProductController : Controller
{
    private static List<Product> _products = new()
    {
        new Product(1, "Laptop", 999.99m),
        new Product(2, "Mouse", 19.99m)
    };

    public IActionResult Index()
    {
        return View(_products);
    }

    public IActionResult Create()
    {
        return View();
    }

    [HttpPost]
    public IActionResult Create(Product product)
    {
        if (!ModelState.IsValid)
        {
            return View(product);
        }

        product.Id = _products.Max(p => p.Id) + 1;
        _products.Add(product);

        TempData["SuccessMessage"] = $"Product {product.Name} created successfully!";
        return RedirectToAction(nameof(Index));
    }
}

public record Product(int Id, string Name, decimal Price);

This controller demonstrates TempData usage. After creating a product, we store a success message in TempData before redirecting to the Index action.

@model List<Product>

@if (TempData["SuccessMessage"] != null)
{
    <div class="alert alert-success">
        @TempData["SuccessMessage"]
    </div>
}

<h2>Products</h2>
<table class="table">
    <thead>
        <tr>
            <th>Id</th>
            <th>Name</th>
            <th>Price</th>
        </tr>
    </thead>
    <tbody>
        @foreach (var product in Model)
        {
            <tr>
                <td>@product.Id</td>
                <td>@product.Name</td>
                <td>@product.Price.ToString("C")</td>
            </tr>
        }
    </tbody>
</table>

The view checks for a TempData message and displays it if present. The message will be available only for the next request after being set.

TempData is particularly useful for Post-Redirect-Get (PRG) patterns. It helps avoid form resubmission issues while still providing feedback to the user.

In this example, the success message will be displayed exactly once. If the page is refreshed, the message won't appear again because TempData is cleared after being read.

Source

Microsoft ASP.NET TempData Documentation

In this article, we have explored TempData in ASP.NET 8. This powerful feature simplifies passing data between actions during redirects while maintaining clean application flow.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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