Question

对我所拥有的内容的简短解释：使用名为ManyOnMany的数据透视表在project和user之间建立project_user关系。

在显示某个项目时，会打印一个用户列表，并选中复选框，以便在选中该复选框后立即将其链接到项目（因此它会将user_id + project_id发送给pivot table

enter image description here

现在问题。当我们将用户（例如Admin der Liam）链接到项目时它将起作用并且数据将被发送到数据库。但是当再次取消选中该复选框时，它将发出Call to a member function users() on a non-object错误，而不是清除表并仅将选中的框放入数据库

控制器：

public function edit($id, Project $project)
{
    $users = User::with('projects')->get();

    $project = $this->project->find($id);

    return view('project.edit', ['project' => $project, 'id' => 'edit', 'project_id' => $id, 'users' => $users]);  
}  


public function update(CreateProjectRequest $request)
{
    if($request->get('contribute'))
    {
        foreach($request->get('contribute') as $k => $contribute)
        {
            if($contribute == 1)
            {
                $project = $this->project->find($request->project_id);
                $keys[] = $k;
            }
        }
    }
    $project->users()->sync($keys);

    $project = $this->project->find($request->project_id);
    $project->fill($request->input())->save();

    return redirect('project');
}

HTML /刀片：

@if(isset($users))
@foreach($users as $user)
    <tr>
        <td>
             {{$user->firstname}} {{$user->middlename}} {{$user->lastname}}
        </td>
        <td>
             {!! Form::checkbox('contribute['.$user->id.']', '1', $user->projects->contains($project->id)) !!}
        </td>
   </tr>
@endforeach
@endif

Answer 1

你的$项目是空的，因为你在foreach中声明了$ project。尽量在foreach之外宣布它。

Answer 2

将$project->users()->sync($keys);放在while循环中$project = $this->project->find($request->project_id);之后。初始化对象后，应该同步$项目。

foreach($request->get('contribute') as $k => $contribute)
{
    if($contribute == 1)
    {
        $project = $this->project->find($request->project_id);
        $keys[] = $k;
        $project->users()->sync($keys);
    }
}

Answer 3

public function update(CreateProjectRequest $request)
{
    $this->project = $this->project->find($request->project_id);
    if($request->get('contribute'))
    {
        foreach($request->get('contribute') as $k => $contribute)
        {
            if($contribute == 1)
            {
                $keys[] = $k;
            }
        }
    }

    if(isset($keys)) {
        $this->project->users()->sync($keys);
    }
    else {
        $this->project->users()->detach();
    }

    $this->project = $this->project->find($request->project_id);
    $this->project->fill($request->input())->save();

    return redirect('project');
}

Laravel sync（）方法错误

3 个答案: