Laravel model binding for select dropdown

问题:

I want the select dropdown value to be selected in my edit form.

In my controller

public function edit($id)
{
    $vedit = DB::table('vehicles')->where('id', $id)->first();
    $cartype= DB::table('car_category')->pluck('cartype'); 
    return view('vehicles.edit', compact('vedit','cartype'));
}

In view

{{ Form::label('Vehicle Type', 'Vehicle Type') }}
<select name="vehicle_type" class="form-control">
  @foreach($cartype as $cartypes)   
  <option value="{{ $cartypes}}">{{ $cartypes}}</option>
  @endforeach
</select>

How can I achieve this?

回答1:

You can add selected attribute if it's the choosen one like this :

{{ Form::label('Vehicle Type', 'Vehicle Type') }}
<select name="vehicle_type" class="form-control">
    @foreach($cartype as $cartypes) 
        <option value="{{ $cartypes}}" {{ $cartypes == $vedit->vehicle_type ? 'selected' : ''}}>{{ $cartypes}}</option>
    @endforeach
</select>

回答2:

What version of Laravel are you using ? Looks like you're using Laravel Collective Form facade.

In that case, this should work fine:

{!! Form::label('Vehicle Type', 'Vehicle Type') !!}
{!! Form::select('vehicle_type', $cartype, $vedit->vehicle_type ?: old('vehicle_type), ['class' => 'form-control']) !!}

Assuming $vedit->vehicle_type is your previously stored vehicle type. So it will pre-select that when editing. In case of creating new, old('vehicle_type') should persist the previously selected value on failed validations.

回答3:

By calling pluck() an array of values is already returned for the car types.

So just use it like this natively with Laravel Collective:

{!! Form::label('Vehicle Type', 'Vehicle Type') !!}
{!! Form::select('vehicle_type', $cartype, null, ['class' => 'form-control']) !!}

Note, I have also changed your double curly braces. The double curly braces escape the output - given the Form facade returns HTML code, you want this to be unescaped.

More info on generating drop down lists with Laravel Collective; https://laravelcollective.com/docs/5.4/html#drop-down-lists

Edit show currently selected value and old value if form fails validation:

{!! Form::label('Vehicle Type', 'Vehicle Type') !!}
{!! Form::select('vehicle_type', $cartype, old('vehicle_type', $vedit->vehicle_type), ['class' => 'form-control']) !!}