Sending Data from Local Storage to a SQL Database in a Blazor App

Learn how to effectively transfer data from local storage to a SQL database in your Blazor application and ensure proper submission of user input through button clicks.
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How to Send Data from Local Storage to a SQL Database from a Button Click in a Blazor App

Developing a Blazor application comes with its challenges, especially when you want to smoothly transition data from local storage to a SQL database upon a button click. In this guide, we will tackle the specific issue of ensuring that user input stored in local storage is sent to a SQL database when a submit button is clicked.

Understanding the Situation

Imagine you’re developing a Blazor app for electronic recycling where employees can input data through forms that are saved locally. After users confirm their entries on a summary page, they hit a submit button to save this data into a SQL database. However, your button isn’t performing as expected. It’s crucial that the application checks whether a specific CPSNumber exists in the database and either updates the record or adds a new entry accordingly.

The Solution

1. Identifying the Issue

The primary problem was the button’s click event not registering correctly. Initially, the submit button was coded with the @onclick attribute and awaited a function call, which led to nothing happening upon clicking. To resolve this, you need to ensure that the button call is handled correctly.

2. Correcting the Button Click Event

To ensure the button functions properly, you need to correct how the function is bound to the button's click event. The appropriate code is:

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

Why This Works: This corrected version directly invokes the function on button click without using the asynchronous @onclick. As a result, the button correctly registers the click event, executing the YourSaveFunction.

3. Implementing the Save Function

Make sure your YourSaveFunction is set up to handle data retrieval from local storage and to check against the SQL database. Here’s what your function might look like:

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

4. Layering the Data Handling Logic

Here’s a breakdown of the logic you'll implement within your SaveUserData method in the CSPNumerManager class:

Retrieve the saved data from local storage.

Loop through the retrieved list, checking each CPSNumber against the database to determine if it exists.

Update the record if it does, otherwise add a new entry.

5. Complete Sample Code Snippet

Here’s how the data processing might be structured:

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

Conclusion

By correcting the check in your button click event from an asynchronous approach to a direct click method, you enable the desired functionality in your Blazor application. From retrieving data from local storage to ensuring it’s properly inserted or updated in the SQL database, the solution lays a robust foundation for your app’s data management.

If you’ve faced similar challenges in your Blazor development journey, feel free to share your experiences in the comments! Happy coding!