Скачать или смотреть Fix Sorting Issue in Angular Mat-Table for Calculated Columns

Resolve the sorting problem in Angular's mat-table when dealing with calculated columns, specifically addressing the 'Total' column issue.
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Fixing the Sorting Issue in Angular Mat-Table for Calculated Columns

If you're working with Angular and using the Material table (mat-table), you might encounter an issue where sorting works for all columns except for a specific one—often a column that calculates totals from other columns. In this guide, we’ll explore a common problem and provide a clear, step-by-step solution to ensure all your columns, including the Total column, can be sorted effectively.

The Problem

In your Angular application, you have implemented a material table that displays various data, including a Total column that aggregates values from other columns. The typical setup involves defining columns and setting up sorting features alongside data sources. However, you discovered that the Total column does not sort correctly. This could stem from several factors, including how the data is structured and how the total is being calculated.

Here's a brief overview of the issue:

The Total column was not part of the item object from which the table draws data.

The calculation for the total was being performed using a method (getTotalDataOfItem) right before rendering the table, which is not ideal for sorting.

The Solution

After some attempts to troubleshoot, the issue can be resolved by ensuring the Total value is included in every item object and adjusting the template for rendering. Here’s how to effectively fix this:

1. Modify the Data Structure

To ensure the Total column is sortable, you need to add total directly to each item in your data. This requires a small modification in your TypeScript file.

Implementation

Add the following code in your ngOnInit method:

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

2. Update the HTML Template

Once you have integrated the total property into your data, the next step is to adjust how the Total column is rendered in the HTML template.

Updated Template Code

Replace the existing definition for the Total column with the following:

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

3. Result

With these changes, your Total column is now a part of each item object, allowing the Angular Material table to treat it like any other column. As a result, it will be sortable, just like the other columns.

Conclusion

By making these simple adjustments to your data structure and template, you can effectively resolve the sorting issue in your Angular Material table for calculated columns. Now you can enjoy seamless sorting across all fields, including the Total column!

If you found this guide helpful or if you have further questions, feel free to reach out. Happy coding!