如何将select组件数据传递至控制器？功能实现遇阻求助

Let's break down the issues in your code step by step—there are a few simple fixes needed to get your category filter working:

1. Syntax Error in <option> Tags #

Your option elements have a typo in the value attribute: you wrote value'...' instead of value="...". This makes the value attribute invalid, so no data gets sent when the form submits.

Fix it like this:

<option value="<?php echo $row->id; ?>"><?php echo $row->name; ?></option>

2. Missing echo for form_close() #

In CodeIgniter, form_close() returns the closing </form> tag as a string, but you're not echoing it. This means your form isn't properly closed, which can break form submission. Always echo it to render the closing tag:

<?php echo form_close(); ?>

3. No Way to Submit the Form #

By default, a <select> element won't submit the form on its own. You have two practical options here:

Option A: Add a Submit Button

Add a button inside the form to let users trigger the submission manually:

<button type="submit">Apply Filter</button>

Option B: Auto-Submit on Select Change

Use JavaScript to automatically submit the form when the user selects a category. Add this script right before closing the form:

<script>
document.querySelector('select[name="category"]').addEventListener('change', function() {
    this.form.submit();
});
</script>

4. Controller Adjustments (For Your End Goal) #

Your current myFunction() is just echoing the value, but to load the new model/data and stay on the same view, you'll want to modify it to fetch filtered data and pass it back to your view. Here's an example:

public function myFunction() {
    // Get the selected category ID (use post or get depending on your form method)
    $category_id = $this->input->post('category');
    
    // Load your model
    $this->load->model('Category_model');
    
    // Fetch filtered data using the category ID
    $data['filtered_results'] = $this->Category_model->get_items_by_category($category_id);
    // Pass the category list again for the select dropdown
    $data['cat'] = $this->Category_model->get_all_categories();
    
    // Load your view with the filtered data
    $this->load->view('your_view_name', $data);
}

If you prefer to use GET requests (so the filter appears in the URL, making bookmarkable links), update your form open to use GET:

<?php echo form_open('Welcome/myfunction', ['method' => 'get']); ?>

Then fetch the value with $this->input->get('category') instead of post.

Putting it all together, your fixed view would look like this:

<?php echo form_open('Welcome/myfunction'); ?>
<select name="category">
    <option value="">filter</option>
    <?php foreach ($cat->result() as $row): ?>
        <option value="<?php echo $row->id; ?>"><?php echo $row->name; ?></option>
    <?php endforeach; ?>
</select>
<button type="submit">Apply Filter</button>
<script>
// Optional auto-submit on selection
document.querySelector('select[name="category"]').addEventListener('change', function() {
    this.form.submit();
});
</script>
<?php echo form_close(); ?>

内容的提问来源于stack exchange，提问作者Oriol