如何在 laravel 的选择选项值中显示选定的标签？

Question

这是我的帖子创建视图

<div class="col-lg-12">
    <form action="{{ route('admin.post.store') }}" enctype="multipart/form-data" method="post">
        {{ csrf_field() }}
        <div class="form-group">
            <label for="title">Post Title</label>
            <input type="text" class="form-control" value="{{ old('title') }}" name="title" id="title"
                   placeholder="Enter Post Title">
            <span class="text-danger">{{ $errors->first('title') }}</span>
        </div>
        <div class="form-group">
            <label for="slug">Post Image</label>
            <input type="file" class="form-control" name="image" id="image"
                   placeholder="Select Post Image">
            <span class="text-danger">{{ $errors->first('image') }}</span>
        </div>
        <div class="form-group">
            <label for="tags">Select Tags</label>
            <select multiple class="form-control" name="tags[]" id="tags">
                @foreach($tags as $id => $name)
                    <option id="{{ $id }}">{{ $name }}</option>
                @endforeach
            </select>
        </div>
        <div class="form-group">
            <textarea class="body" name="body">{{ old('body') }}</textarea>
            <span class="text-danger">{{ $errors->first('body') }}</span>
        </div>
        <div class="form-group">
            <label for="category">Select Category</label>
            <select class="form-control" name="category" id="category">
                <option value="">Select</option>
                @foreach($cats as $cat)
                    <option value="{{ $cat->id }}">{{ $cat->name }}</option>
                @endforeach
            </select>
        </div>
        <button type="submit" class="btn btn-success btn-block">Publish</button>
    </form>
</div>

标签有多对多的关系。 在这里我可以选择很多标签，但是在帖子编辑视图中我看不到我在帖子创建视图中选择的标签。 我想在选择选项值和编辑主题中显示选定的标签。

发布更新方法：

public function edit(Post $post)
{
    $tags = Tag::all()->pluck('name', 'id');
    $cats = Category::all();
    return view('admin.post.edit', compact(['post', 'cats', 'tags']));
}

public function update(Post $post, Request $request)
{
    $this->validate($request, [
        'title' => 'required|min:3|max:255',
        'slug' => 'nullable|string',
        'image' => 'sometimes|mimes:jpeg,bmp,png,jpg,gif',
        'body' => 'required',
        'category' => 'nullable',
        'views' => 'nullable',
        'tags' => 'nullable',
    ]);

    $post->title = $request->title;
    $post->slug = $request->slug;
    $post->body = $request->body;
    $post->category_id = $request->category;

    if ($request->hasFile('image')) {
        $image = $request->file('image');
        $filename = time() . '.' . $image->getClientOriginalExtension();
        $location = public_path('images/' . $filename);
        Image::make($image)->resize(800, 400)->save($location);

        $oldfilename = $post->image;

        $post->image = $filename;

        Storage::delete($oldfilename);
    }

    $post->save();

    $post->tags()->sync($request->tags, false);

    Session::flash('update', 'Post Updated Successfully');

    return redirect()->route('admin.post.index');
}

发布编辑视图：

<div class="col-lg-12">
    <form action="{{ route('admin.post.update',$post->id) }}" enctype="multipart/form-data" method="post">
        {{ csrf_field() }}
        {{ method_field('patch') }}
        <div class="form-group">
            <label for="title">Post Title</label>
            <input type="text" class="form-control" value="{{ $post->title }}" name="title" id="title"
                   placeholder="Enter Post Title">
            <span class="text-danger">{{ $errors->first('title') }}</span>
        </div>
        <div class="form-group">
            <label for="slug">Post Image</label>
            <input type="file" class="form-control" name="image" id="image"
                   placeholder="Select Post Image">
            <span class="text-danger">{{ $errors->first('image') }}</span>
        </div>
        <div class="form-group">
            <label for="tags">Select Tags</label>
            <select class="js-example-basic-single form-control" name="tags[]" id="tags" multiple="multiple">

            </select>
        </div>
        <div class="form-group">
            <textarea class="body" name="body">{{ $post->body }}</textarea>
            <span class="text-danger">{{ $errors->first('body') }}</span>
        </div>
        <div class="form-group">
            <label for="category">Select Category</label>
            <select class="form-control" name="category" id="category">
                <option value="">Select</option>
                @foreach($cats as $cat)
                    <option <?php if ($cat->id == $post->category_id) {
                        echo 'selected';
                    } ?> value="{{ $cat->id }}">{{ $cat->name }}</option>
                @endforeach
            </select>
        </div>
        <button type="submit" class="btn btn-primary btn-block">Edit</button>
    </form>
</div>

这里：

<div class="form-group">
    <label for="tags">Select Tags</label>
    <select multiple class="form-control" name="tags[]" id="tags">
        @foreach($tags as $id => $name)
            <option id="{{ $id }}">{{ in_array($id,$post->category()->pluck('id')->toArray()) ? 'selected' : '' }}</option>
        @endforeach
    </select>
</div>

如何从数据库中传递选定的帖子标签并在此处显示主题并进行编辑。

我正在使用 select2 插件

在 select2 中我应该在 jQuery 中传递数据：

$('.js-example-basic-single').select2().val({{ json_decode($post->tags()->getRelatedIds()) }}).trigger('change');

但它不起作用:(

我得到了这个错误

方法 Illuminate\Database\Query\Builder::getRelatedIds 不存在。 （查看：C:\Users\M0RT3Z4\Desktop\MyBlog\resources\views\admin\post\edit.blade.php

请帮助我，谢谢！

Answer 1

你把代码放错地方了：

试试这个：

<div class="form-group">
    <label for="tags">Select Tags</label>
    <select multiple class="form-control" name="tags[]" id="tags">
        @foreach($tags as $id => $name)
        <option id="{{ $id }}" {{ in_array($id,$post->category()->pluck('id')->toArray()) ? 'selected' : '' }}>{{ $name }}</option>
        @endforeach
    </select>
</div>