链式下拉菜单中的默认值

Question

我是 ajax 的新手，所以我正在学习，我被困住了，试图到处搜索我需要的东西却无济于事。我有一个包含位置列表的下拉列表。但是，基于另一个下拉列表，我想将默认位置返回到列表中。因此，如果我选择资产 A，它的默认位置将自动填充在下拉列表中，但仍会通过 $locations 列表为我提供选择其他位置的选项。我可以将正确的数据返回给 div，但我不知道如何在下拉列表中填充它。下面是我填充 div 的内容。任何有关如何将其发送到 $locations 列表的下拉列表的帮助，但此值作为默认选择将不胜感激。

下拉菜单

    <div class="form-group">
                    <label class="control-label" for="asset_id" id="asset_id" >
                        Asset
                    </label>
                    <?php
                    echo $this->Form->input( 'WorkorderAsset.0.asset_id', array(
                    'type'=>'select',
                    'data-placeholder'=>'Select An Asset Type From Above...',
                    'class'=>'chzn-select form-control asset',
                    'empty' => true,
                    'id'=>'asset',
                    'label'=>false,
                    'after' => '<div class="input-group-addon"><i class="fa fa-exclamation text- 
       danger"></i></div></div>',
                    'between' => '<div class="input-group">',
                                            ));
                    ?>
                </div>


    <div class="row">
                <div class="col-md-6">
                    <?php
                    echo $this->Form->input( 'location_id', array(
                    'id'=> 'location',
                    'options'=>$locations,
                    'class'=>'chzn-select form-control',
                    'empty' => true,
                    'z'=>'Select A Location',
                    'required'=>false,
                    'between' => '<div class="input-group">',
                    'after' => '<div class="input-group-addon"><i class="fa fa-exclamation text- 
                     danger"></i></div></div>',
                                            ));
                    ?>
                <div class="row">
                    <div class="col-md-6">






  $('#asset').on('change', function() {
        var id = $('#asset').val();     
        if (id != "") {
            $.ajax({
                type: 'POST',
                url: '/workorders/workorders/getInfo/'+ id +'.json',
                dataType: 'html',
                beforeSend: function(xhr) {
                    $(".overlay").show();
                    xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
                },
                success: function( response ) {
                    console.log(response);
                    $('#location').html(response);
                },
                error: function (jqXHR, textStatus, errorThrown) {
                    console.log(jqXHR);
                    console.log(textStatus);
                    console.log(errorThrown);
                },
                complete: function() {
                    $(".overlay").hide();
                },
            });

        }
        
else {
            alert("Please select an asset");

        }
                
            });

在我的控制器中

public function getInfo($id=null)
{
    
    $locate = $this->request->data = $this->Asset->find('first', array(
    'conditions'=>array(
    'Asset.id' => $id
            ),
    'contain'=>array(
    'Location'=>array(
    'fields'=>array('Location.name')
            ),
            )
            ));
    if ($this->request->is('ajax')) {
        $this->set( 'locate', $locate);
        }
}

在我的 JSON 中

 <?php
 $location = (!empty($locate['Location']['name'])) ? $locate['Location']['name'] : '&nbsp;';
 ?>
 <div >

    
        <?  echo "Default Asset Location:" . " " .  $location ?>
    
    
 </div>

Answer 1

我想通了。答案如下。

查看：

 <div class="form-group">
                <label class="control-label" for="asset_id" id="asset_id" >
                    Asset
                </label>
                <?php
                echo $this->Form->input( 'WorkorderAsset.0.asset_id', array(
                'type'=>'select',
                'data-placeholder'=>'Select An Asset Type From Above...',
                'class'=>'chzn-select form-control asset',
                'empty' => true,
                'id'=>'asset',
                'label'=>false,
                'after' => '<div class="input-group-addon"><i class="fa fa-exclamation 
text- 
   danger"></i></div></div>',
                'between' => '<div class="input-group">',
                                        ));
                ?>
            </div>


<div class="row">
            <div class="col-md-6">
                <?php
                echo $this->Form->input( 'location_id', array(
                'id'=> 'location',
                'options'=>$locations,
                'class'=>'chzn-select form-control',
                'empty' => true,
                'z'=>'Select A Location',
                'required'=>false,
                'between' => '<div class="input-group">',
                'after' => '<div class="input-group-addon"><i class="fa fa-exclamation 
text- 
                 danger"></i></div></div>',
                                        ));
                ?>
            <div class="row">
                <div class="col-md-6">



    $('#asset').on('change', function() {
        var id = $('#asset').val();

        if (id != "") {
            $.ajax({
                type: 'POST',
                url: '/workorders/workorders/getInfo/'+ id +'.json',
                dataType: 'html',
                success: function( response ) {
                    console.log(response);
                
        
                    $("#location").attr("data-placeholder", response);
                    $('#location' ).val('').trigger( 'chosen:updated' );
                },
                error: function (jqXHR, textStatus, errorThrown) {
                    console.log(jqXHR);
                    console.log(textStatus);
                    console.log(errorThrown);
                },
                complete: function() {
                    $(".overlay").hide();
                },
            });

        }
        
else {
        }
                
            });

控制器：

public function getInfo($id=null)
{

    if (!$id) {
        throw new NotFoundException();
        }

    $locate = $this->Asset->find('first', array(
    'conditions'=>array(
    'Asset.id'=>$id
        ),
    'contain'=>array(
    'Location'=>array(
    'fields'=>array(
    'Location.id',
    'Location.name',
        ),
    'order'=>array('Location.name'=> 'asc')
        )
        )
        ));

    #pr($groupSelection);
    #exit;

    $this->set(compact('locate'));
}

JSON

  <?php
  if (!empty($locate['Location'])) {
      echo '<option value="' . $locate['Location']['id']  . '">' . $locate['Location'] 
 ['name'] . '</option>';
  }
   else {
      echo '<option value="">' . __('No Options Available') . '</option>';
  }
  ?>