old() does not work on dependent dropdown in Laravel blade - laravel

Question

I have two dropdown list in my Laravel page. I am trying to get old value of the dependent dropdown list (categorylist.blade) and make it selected once I fill and post the data. It returns back to the same page if the validation has not successfully completed. I am able to get all values except this one. I have tried Session::put() as well as Session::flash() but did not work. The category list is retrieved once you chose section as it requests the category list from the controller through ajax. How can I get the old value in the category dropdown list after the page refreshed.
Here is my section selection dropdown:
<select class="form-control sectionchoose" name="section_id" id="section_id">
<option value="">Choose Section</option>
#foreach($sections as $section)
<option value="{{$section['id']}}" #if(old('section_id') == $section['id']) selected #endif>{{$section['name']}} </option>
#endforeach
</select>
My categorylist dropdown:
<label class="col-sm-6">Chose Category</label>
<div class="categorylist">
#include('admin.deal-management.categorylist')
</div>
And this is my categorylist view file:
<select class="form-control " name="category_id" id="category_id">
<option value="">Choose Category</option>
#foreach($categories as $category)
<option value="{{$category['id']}}" #if(old('category_id') == $category['id']) selected #endif>
{{$category['category_name']}}
</option>
#endforeach
</select>
and this is my main controller:
public function addEditDeals(DealAddEditRequest $request, $id=null){
//*** post starts here ***/
if($request->isMethod('post')){
$message = 'Updated successfully';
$data=$request->all();
$deal->fill($request->validated());
$deal->save();
return redirect()->back()->with($message);
}
This is my categorylist controller:
public function findCategories(Request $request){
if($request->json()){
$data = $request->all();
$categories = Category::where(['section_id' => $data['id'], 'status'=>1])->get()->toArray();
return view('admin.deal-management.categorylist',compact('categories'));
}
}
And finally, this is the jQuery part:
$(document).ready(function (){
let sectionid = $('.sectionchoose').val();
$.ajax({
headers: {
'X-CSRF-TOKEN' : $('meta[name="csrf-token"]').attr('content')
},
type: 'POST',
datatype: 'json',
url : '/admin/selectsection',
data: {id:sectionid},
success: function(response){
$('.categorylist').html(response)
}, error:function(){
}
})
})

Answer 1

Finally, I was able to find the solution. Whoever has the same issue can use the approach below:
Step 1: Send the Session value through the with() command:
return redirect()->back()->withErrors($validator)
->withInput()->with('cat_id',$data['category_id']);
}
Step 2: Retreive the data in your main blade and attain hidden input:
<input class="cat_id" id="asd" type="hidden" value="{{Session::get('cat_id')}}"/>
Step 3: Get the retreived session value in Jquery:
$(document).ready(function (){
let sectionid = $('.sectionchoose').val();
let cat_id;
if($('#asd').val()){
cat_id = $('#asd').val();
} else {
cat_id = 0;
}
$.ajax({
headers: {
'X-CSRF-TOKEN' : $('meta[name="csrf-token"]').attr('content')
},
type: 'POST',
datatype: 'json',
url : '/admin/selectsection',
data: {id:sectionid, cat_id:cat_id},
success: function(response){
$('.categorylist').html(response)
}, error:function(){
}
})
})
Step 4: Send the session value to your dependent blade again (as cat_id here)
public function findCategories(Request $request){
if($request->json()){
$data = $request->all();
$cat_id = $data['cat_id'] ?? '';
$categories = Category::where(['section_id' => $data['id'], 'status'=>1])->get()->toArray();
return view('admin.deal-management.categorylist',compact('categories','cat_id'));
}
}
Done! As far as I know, there is not any other way to get old value of dependent dropdown list value so far.