使用 laravel 8 在从数据库中获取的下拉列表中显示数据

Question

我必须在产品形式的下拉列表中显示类别值，给定的代码来自我的观点，错误未定义 $categories.this 是我在 laravel 中的第一个代码我不知道如何更改其他 files.which 变量用于 foreach？或者我必须在 ProductController 中创建新函数？

<form action="/upload_product" method="post">
    @csrf
    <label>Choose Categories</label>
    <select name="category_id" id="category" class="category">
        <option disable selected>--select category--</option>
        @foreach($categories as $item)
        <option value="{{ $item->id }}">{{ $item->name}}</option>
    @endforeach
    </select>
        <input type="text" name="name" placeholder="name">
        <input type="number" name="sale_price" placeholder="sale_price">
   </form>

型号Product.php

        class Product extends Model
           {
     use HasFactory; 
     protected $table = 'products';
     public $timestamps = true;

    public function category(){
    return $this->belongsTo('App\Models\Category');
}

} 型号 Category.php

   class Category extends Model
  {
    use HasFactory;
    public $fillable = [ 'name' ];
    protected $dates = [ 'deleted_at' ];
    public $timestamps = true;

    public function products (){
    return $this->hasMany('App\Models\Product');
  }
}

ProductController.php

   <?php
 namespace App\Http\Controllers; 
 use App\Models\Product;
 use App\Models\Category;
 use Illuminate\Http\Request;

class ProductController extends Controller
{ 
  public function index()
{
    $products = Product::all(); 
    return view('products/index', ['products'=>$products]);
}
 public function view()
{
  $products = Product::with('category')->get(); 
  $categories = Category::with('products')->get();
  return view ('product.view')-> with([
    'products' => $products,
    'categories' => $categories,
]);
}

Answer 1

您的索引文件中没有 $categories。根据 index 方法，您发送的只是产品：

public function index()
{
    $products = Product::all(); 
    return view('products/index', ['products'=>$products]);
}

所以也添加类别。

Answer 2

你必须像下面这样使用

public function index(){
    $products   = Product::all(); 
    $categories = Category::with('products')->get();
    return view('products.index', compact('products','categories'));
}

Answer 3

  public function index()
{


 $products = Product::get(); 
    return view('products/index', ['products'=>$products]);

}

Answer 4

您可以通过三种方式做到这一点

public function index(){
    $products   = Product::all(); 
    $categories = Category::with('products')->get();
    return view('products.index', compact('products','categories'));
}

public function index(){
    $products   = Product::all(); 
    $categories = Category::with('products')->get();
    return view('products.index')->with(['products'=>$products,'categories'=>$categories]));
}

public function index(){
        $data['products']   = Product::all(); 
        $data['categories'] = Category::with('products')->get();
        return view('products.index',$data);
    }

使用 laravel 8 在从数据库中获取的下拉列表中显示数据

show the data in dropdown fetched from database using laravel 8

laravel

drop-down-menu