我正在做一个关于我在Twilio上的账户的项目。我想使用Chart.js库从我的控制台获取所有出站呼叫，并在环形图上显示它们的状态（已完成，无应答，忙碌，失败）。在运行调试时正确检索所有数据。唯一的问题是显示图表。

public async Task<IActionResult> GetAllCalls()
{
        List<string> status = new List<string>();
        ReceivedCallModel model = new ReceivedCallModel();
        var request = new HttpRequestMessage(HttpMethod.Get, $"https://api.twilio.com/2010-04-01/Accounts/{Account_Sid}/Calls.json?StartTime=2023-06-22");
        var client = _httpClientFactory.CreateClient("MyClient");
        HttpResponseMessage response = await client.SendAsync(request);
        if(response.StatusCode == HttpStatusCode.OK)
        {
            var jsonString = await response.Content.ReadAsStringAsync();
            model = JsonConvert.DeserializeObject<ReceivedCallModel>(jsonString);
            foreach(var call in model.calls)
            {
                if(call.direction == "outbound-api")
                {
                    status.Add(call.status);
                    ViewBag.States = status;
                }
            }
            TempData["success"] = "Successful";
        }
        return View(model);
}

@model ReceivedCallModel
<div class="container">
    <div class="row justify-content-center">
        <div class="col-sm-6">
            <div class="card border-0">
                <div class="card-body">
                    <canvas id="chart">
                    </canvas>
                </div>
            </div>
        </div>
    </div>
</div>

@section Scripts{
    <script type="text/javascript">
        var canvaschart = document.getElementById("chart");
        var completed = [];
        var no_answer = [];
        var busy = [];
        var failed = [];
        @if(TempData["success"] != null){
            foreach(var item in ViewBag.States){
                if(item == "completed"){
                    @: completed.push(@item);
                }
                else if(item == "no-answer"){
                    @: no_answer.push(@item);
                }
                else if(item == "busy"){
                    @: busy.push(@item);
                }
                else if(item == "failed"){
                    @: failed.push(@item);
                }
            }
        }
        const data = {
            labels: [
                'completed',
                'no-answer',
                'busy',
                'failed'
            ],
            datasets: [{
                label: 'Call Status',
                data: [completed.length, no_answer.length, busy.length, failed.length],
                backgroundColor: [
                    'rgb(20, 205, 86)',
                    'rgb(54, 162, 235)',
                    'rgb(255, 205, 86)',
                    'rgb(255,0,0)'
                ],
                hoverOffset: 4
            }]
        };

        var barchart = new Chart(canvaschart, {
            type: 'doughnut',
            data: data
        });

    </script>
}

它成功地显示了TempData值，而没有显示图表。