我没有尝试刷新刀片式服务器上的现有图表。这里的情况下，每个模块都有一个问题，选项和答案（由用户选择的选项）的列表。我有一个下拉菜单来按模块筛选问题。
我设法在加载时为第一个模块动态生成图表，但当我更改为模块2时，chartData会更新并通过emit传递回脚本，但我无法更新刀片。我得到的错误是，Uncaught（in promise）TypeError：无法从const ctx = document.getElementById（canvasId）.getContext（'2d'）读取4：2072：66的null（阅读'getContext'）的属性;.
我也提到了这个Destroy chart.js bar graph to redraw other graph in same ，任何帮助是赞赏。
Livewire组件

public function mount()
{
    $this->modules = $this->session->course->modules->where('status', 'PUBLISHED');
    $this->selectedModule = $this->modules->first()->id;
    $this->GetQuestions();
    $this->preparePieChartData();
}
public function preparePieChartData()
{
    $singleChoiceQuestions = $this->questions->where('type', 'single_choice');
    $data = [];
    foreach ($singleChoiceQuestions as $question) {
        if ($question->answers->count() > 0) {
            $options = $question->options;
            $questionData = [
                'question' => $question->question_text,
                'options' => [],
            ];
            foreach ($options as $option) {
                $count = $question->answers
                    ->where('option_uuid', $option->uuid)
                    ->where('session_id', $this->session->id)
                    ->count();
                $questionData['options'][] = [
                    'option' => $option->option_text,
                    'count' => $count,
                ];
            }
            $data[] = $questionData;
        }
    }
    $this->chartData = $data;
    
    $this->emitSelf('chartDataUpdated', $data);
}
public function updatedSelectedModule()
{
    $this->GetQuestions();
    $this->preparePieChartData();
}

字符串
在刀刃上

<select class="form-control-sm form-control" wire:model="selectedModule">
    @foreach($modules as $module)
        <option value="{{ $module->id }}">{{ $module->title }}</option>
    @endforeach
</select>
@foreach($questions as $question)
    if ($question->type == 'single_choice')
        <canvas id="pieChart{{ $loop->index }}" style="max-height: 300px; display: block;"></canvas>
    @endif
@endforeach

型
在刀锋剧本的结尾

<script>
    document.addEventListener('livewire:load', function () {
        const chartInstances = [];
        function GenerateCharts(chartData) {
            console.log('drawing charts...');
            chartData.forEach((chart, index) => {
                console.log(index);
                console.log(chart);
                const config = {
                    type: 'pie',
                    data: {
                        labels: chart.options.map(option => option.option),
                        datasets: [{
                            label: 'Total',
                            data: chart.options.map(option => option.count),
                        }]
                    },
                    options: {
                        plugins: {}
                    },
                }
                const canvasId = `pieChart${index}`;
                if (chartInstances[canvasId]) {
                    chartInstances[canvasId].destroy();
                    delete chartInstances[canvasId];
                }
                const ctx = document.getElementById(canvasId).getContext('2d');
                chartInstances[canvasId] = new Chart(ctx, config);
            });
        }
        GenerateCharts(@js($chartData));
        @this.on('chartDataUpdated', (data) => {
            GenerateCharts(data);
        });
    });
</script>

型