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Discover how to get integer values from ENUM selections in JavaScript instead of enum names when using ASP.NET MVC's dropdown lists.
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How to Retrieve the Integer Value of ENUMs in JavaScript from a Dropdown List

When dealing with dropdown lists that make use of Enum values in an ASP.NET MVC application, it's common to face challenges when trying to retrieve the selected value. Specifically, many developers encounter a situation where they want to grab the integer value associated with the selected Enum, rather than the Enum’s name. If you've faced this issue, you're not alone! In this guide, we'll explore how to effectively retrieve the integer value of ENUMs in JavaScript when a user makes a selection in a dropdown list.

The Problem

Imagine you have a dropdown list populated with Enum values representing user roles in your application. For instance, you might have roles such as ADMINISTRATOR, APPROVER, and ORDER, each linked to integer values for backend processing. When a user selects a role, you need to access the corresponding integer value to perform certain actions, such as permissions checks or role assignments.

Your current implementation might look something like this:

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

The issue arises when you attempt to retrieve the selected value using the following JavaScript function:

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

You’ll notice that this alerts the name of the Enum (like ORDER) rather than its integer value (like 3).

The Solution

To resolve this problem, you need to adjust the way the dropdown list is populated. Instead of simply passing the Enum values directly, you should transform them into a KeyValuePair format that associates both the integer and the name. Here’s how you can implement this:

Step-by-Step Implementation

Use SelectList Constructor with KeyValuePair:
Replace your existing SelectList instantiation with the following revised code:

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

This code does the following:

It retrieves the Enum values from UserRole.

It casts these values to a list that creates key-value pairs, where the key is the integer value of the Enum and the value is its string name.

Access the Selected Integer in JavaScript:
Now that the dropdown list is structured to provide key-value pairs, the getRoleInformation function can remain the same. When a user selects a role, value.value will now return the integer value instead of the name.

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

Conclusion

By implementing the above solution, you can successfully retrieve the integer representation of Enum values from a dropdown list in your JavaScript code, facilitating more effective data handling in your ASP.NET MVC application. Keep this approach in mind whenever you’re working with Enums and dropdown lists, as it streamlines the process of obtaining the data you need without confusion.

With clear structure and organization, you now have the tools necessary to tackle ENUMs in your JavaScript frameworks effectively. Happy coding!