How to Effectively Send Large Data from View to Controller in MVC: A Practical Solution

Learn the best practices for sending large data from the view to a controller in MVC, avoiding common errors like HTTP 404.15 and utilizing ViewModel classes for reliable AJAX requests.
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Handling Large Data Transfers in ASP.NET MVC

When working with ASP.NET MVC, developers often encounter scenarios where they need to send data from a view to a controller, especially when dealing with large datasets. One common issue is when an HTTP request fails due to the size of the data being sent, resulting in errors like "HTTP Error 404.15 - Not Found." In this guide, we’ll explore the root of this issue and provide a reliable solution to handle large data transfers effectively.

The Problem Explained

Imagine you have a form with checkboxes that users can select, and you want to send the selected values as an email list to the server upon submission. The following code snippet showcases a typical implementation:

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

However, upon execution, you receive an error due to the query string exceeding the allowed limit configured in your web server. This is a common pitfall in handling large data transfers.

Why the Error Occurs

The error message indicates that the request filtering module has been configured to deny requests with overly long query strings. Most web servers set a limit on the length of the query string, which, depending on the server configuration, can lead to this issue when sending large amounts of data via GET requests.

Solution Overview

To effectively send large data from the view to a controller in ASP.NET MVC without encountering the 404.15 error, follow these steps:

Switch from GET to POST requests.

Structure your data correctly.

Utilize ViewModels for better organization.

Step-by-Step Solution

1. Update the AJAX Call to Use POST

Instead of using a GET request, which has limitations on the amount of data it can send, switch to the POST method:

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

2. Modify the Controller

The next step is to update the controller action. Change the HTTP method attribute from [HttpGet] to [HttpPost].

Here’s how your controller method should look:

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

3. Employ ViewModels for Better Data Organization

For even greater reliability and clarity, consider using a ViewModel. This allows you to encapsulate the data being sent in a structured way, as shown below:

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

Then update your controller to accept this ViewModel:

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

And finally, modify your AJAX call for the ViewModel:

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

Conclusion

In summary, sending large data from the view to a controller in ASP.NET MVC is manageable with the right approach. By switching to POST requests, restructuring your AJAX calls, and potentially utilizing ViewModels, you can seamlessly handle data without encountering request filtering errors. Implement these techniques in your application for a robust and user-friendly experience.

Now, you're all set to handle large data transfers in your MVC application without the hassle of common pitfalls. Happy coding!