Скачать или смотреть Set formControlName to Template Variable in Angular Forms

Discover how to easily set dynamic `formControlName` in Angular templates using template variables for reactive forms.
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Setting formControlName to Template Variable in Angular Forms

Working with forms in Angular can sometimes pose unexpected challenges, especially when it comes to dynamically binding form controls within templates. In this guide, we will tackle a common problem faced by Angular developers: how to set formControlName to dynamically created template variables within a loop. If you've ever faced the need to create multiple input fields in a reactive form generated by loops, this post is for you!

The Problem

Imagine you're building an Angular application where you need multiple input fields organized in a grid-like structure, formed dynamically from data. You've set up reactive forms and want to bind the formControlName to create unique identifiers for each input based on their position in the grid. However, using static strings is not feasible because you need inputs to be dynamically generated on-the-fly.

Let's examine a specific situation: you have your form with controls that need to reflect a structure like group-i-j as the name for each control in your template. Traditionally, you might see something like this with a plain HTML <span> element as shown below:

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

When you switch from the <span> to an input field, the dynamic aspect is crucial. You want the input field to bind correctly to formControlName using similar expressions, something that isn't immediately clear.

The Solution

To achieve this dynamic control binding, you simply need to modify the formControlName attribute in your input field. By using Angular's interpolation, you can pass the dynamically generated string directly into formControlName as follows:

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

Key Points to Remember

Data-Driven Structure: Your form's structure aligns with the dynamic rows and columns you're creating.

Utilize Angular Interpolation: The expression {{group+ '-'+ i+ '-'+ j}} effectively generates the expected control name.

Ensure Proper FormGroup Setup: If {{this.form.get(group+ '-'+ i+ '-'+ j)?.value}} works, your formGroup likely has been structured correctly in your TypeScript file.

Conclusion

Setting the formControlName using dynamic template variables makes your Reactive Forms more powerful and adaptable. You can easily manipulate and control data without hard-coding field names, leading to cleaner and more maintainable code. If the provided method does not yield the desired outcome, do share your FormGroup structure from your TypeScript file so we can assist further!

Feel free to try out this method in your Angular v12 projects and streamline the way you handle forms with dynamic control names.