Octobercms 后端列表选择的最大限制

Question

我正在开发一个图书馆系统Octobercms，我需要限制每次借书的最大数量，例如：2。这样当你达到selections的数量时，不要请允许我 select 借出更多书籍。

见图： Backend List

请帮帮我！

Answer 1

为了让它工作，我们需要采用 different approach，instead adding error when we are selecting 我们可以抛出错误 when saving，（因为在那里添加 java-script 也有点难它的客户端如此不安全）。

只需将此 code 添加到您的 controller 和 change fields according to need。

public function onRelationManageAdd() {
    $checked = \Input::get('checked');
    $field = \Input::get('_relation_field');
    $maximumAllowed = 2;
    // i have used comment $field you need to replace it with your field
    // this will be your hasMany relational field name
    // also added condition to check selected id is more then 2
    if($field == 'comments' && is_array($checked) && count($checked) > $maximumAllowed) {

        // if selected id is more then 2 we add flash error and return blank array
        \Flash::error('You Can Select Only 2 !');
        return [];
    }

    // ADDITIONAL CHECK if you need more check you can add it here and return error
    if($field == 'comments' && isset($this->params[0])) {
        // currently editing record id.
        $currentEditRecordId = $this->params[0];
        $record = \October\Test\Models\Post::find($currentEditRecordId);
        if($record && $record->comments->count() >= $maximumAllowed) {
            \Flash::error('You Can Select Only 2 !');
            return [];
        }
    }

    // if everything is good then handle request by relation manger 
    //and return response
    return $this->asExtension('RelationController')->onRelationManageAdd();
}

我添加了 ADDITIONAL CHECK 因为这将允许用户 select 2 records per one time，但用户可以 select 2 records multiple time 但我们不允许他们 ;)

你可以添加custom validations你喜欢的。

更新

问题 : select 第一次记录 1 然后 select 另一个记录 - 解决方案

public function onRelationManageAdd() {
    $checked = \Input::get('checked');
    $field = \Input::get('_relation_field');

    $maximumAllowed = 2;
    $count = 0;

    // i have used comment $field you need to replace it with your field
    // this will be your hasMany relational field name
    // also added condition to check selected id is more then 2
    if($field == 'comments' && is_array($checked)) {
        //$count += count($checked);            
        $count = $count + count($checked);         
    }

    // ADDITIONAL CHECK if you need more check you can add it here and return error
    if($field == 'comments' && isset($this->params[0])) {
        // currently editing record id.
        $currentEditRecordId = $this->params[0];
        $record = \October\Test\Models\Post::find($currentEditRecordId);
        if($record) {
            $count = $count + $record->comments->count();
        }
    }

    if($count > $maximumAllowed) {

        // if selected id is more then 2 we add flash error and return blank array
        \Flash::error('You Can Select Only 2 !');
        return [];
    }

    // if everything is good then handle request by relation manger 
    //and return response
    return $this->asExtension('RelationController')->onRelationManageAdd();
}

信息：你可以添加这个relational field in update context当用户adding new record那个时候we don't have information for current record作为当前记录is not saved yet所以 relation count 将 在 第二次检查 和我们的 validation will fail.

中不可用

要避免此问题，您可以为该字段添加更新上下文，该字段将仅在 update.

中可用

banner:
    label: Banner
    oc.commentPosition: ''
    mode: file
    span: auto
    type: mediafinder
    context: update <------ add this option

现在这个字段只会在用户保存记录时显示。我们现在可以很好地进行验证了。

如果您有任何错误，请发表评论。

Octobercms 后端列表选择的最大限制

Octobercm Backend List maximum limit of selections

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