How to Successfully Pass Parameters in ASP.NET MVC Redirects

Learn the best practices for passing parameters in ASP.NET MVC when redirecting between actions, using TempData for complex objects.
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Can't Pass a Parameter When Redirecting to View in ASP.NET MVC

When developing web applications using ASP.NET MVC, you may encounter various hurdles. One common issue developers face is passing parameters between actions during a redirect. In this guide, we will explore a specific challenge related to passing a parameter when redirecting to an action, and how you can effectively resolve it.

The Problem: Missing Parameters in Redirects

While working on your first ASP.NET MVC project, you might find yourself in a scenario where you want to redirect to an action named All and pass parameters—specifically, a query and a page parameter. You might successfully pass the page parameter, but the query is mysteriously missing or returns empty.

In our example scenario, the issue arises when you're calling the Search action, which successfully retrieves data but fails to carry over the query when redirecting to the All action. The code snippet below illustrates the problem:

[[See Video to Reveal this Text or Code Snippet]]

The All action is defined as follows:

[[See Video to Reveal this Text or Code Snippet]]

Despite efforts to change the data type of the query parameter, it still does not pass correctly to the All action.

Understanding the Limitation

The root cause of this issue is that the RedirectToAction() method does not support the transfer of complex objects (like lists) directly as routing parameters. This limitation makes it challenging to pass large or compound data types between actions using standard redirection.

The Solution: Using TempData

To overcome this issue, the implementation of TempData is recommended. TempData allows you to temporarily store data in a session and can be efficiently accessed in subsequent requests (such as the next action).

Step-by-Step Implementation

Store the List in TempData: Instead of attempting to pass the list directly during the redirect, save it in TempData.

[[See Video to Reveal this Text or Code Snippet]]

Retrieve the List in the All Action: In the All action, retrieve the stored list from TempData.

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

In ASP.NET MVC, leveraging TempData is an effective way to manage data when redirecting between actions, particularly when dealing with complex object types like lists. By following the steps outlined above, you can successfully pass parameters during redirects without running into issues.

Now you're equipped to handle this common challenge in ASP.NET MVC development and continue building robust applications. Happy coding!