Cannot visualise chartJS data in ASP .NET Core

Question

I am trying to implement chartJS with ASP .NET Core MVC. I've been trying to make chart that displays data from database (following this tutorial). I have a table "WorkTS" and I need to display data from the following columns: hrPlan, hrFact and hrSub for the year 2021 (Datetime stored in dtMonth column). I'm not getting any error messages, but all I get is a blank space in place of a chart. Here's my code:

Model:

public class WorkTS
    {
        public string? org { get; set; }
        public DateTime? dt { get; set; }
        public decimal? hrFact { get; set; }
        public decimal? hrPlan { get; set; }
        public decimal? hrReestr { get; set; }
        public DateTime? dtSynchro { get; set; }
        public DateTime? dtMonth { get; set; }
        public decimal? hrSub { get; set; }
        public decimal? hrFactWSub { get; set; }
    }

Controller:

public HomeController(ILogger<HomeController> logger, AzureDBContext azcontext)
        {
            _logger = logger;
            _azdb = azcontext;
        }

public async Task<ActionResult> OnGetWorkTSData()
        {
            var month = _azdb.WorkTs.Select(w => w.dtMonth).Distinct().ToArray();
            var plan = _azdb.WorkTs.Select(w => w.hrPlan).Distinct().ToArray();
            var sub = _azdb.WorkTs.Select(w => w.hrSub).Distinct().ToArray();
            var fact = _azdb.WorkTs.Select(w => w.hrFact).Distinct().ToArray();
            return new JsonResult(new { dtMonth = month, hrPlan = plan, hrSub = sub, hrFact = fact });
        }

View:

<div>
<canvas id="workTSChart"></canvas>
</div>
<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
<script>
    function GetJSON_Simple_workTS() {
      var resp = [];
      $.ajax({
         type: "GET",
         url: '@Url.Action("OnGetWorkTSData","home")',
         contentType: "application/json;",
         dataType: "json",
         success: function (data) {
             resp.push(data);
         },
         error: function (req, status, error) {
             alert("error");
         },
         return resp;
             }
    }
    var simpleData = GetJSON_Simple_workTS();
    const config = {
       type: 'bar',
       data: {
           labels: [
                    'ООО МТК',
           ],
       datasets: [{
           label: 'Plan hours',
           backgroundColor: 'rgb(161, 221, 239)',
           borderColor: 'rgb(161, 221, 239)',
           data: simpleData[0].hrPlan,
           },
           {
           label: 'Sub hours',
           backgroundColor: 'rgb(254, 171, 133)',
           borderColor: 'rgb(254, 171, 133)',
           data: simpleData[0].hrSub,
           },
           {
           label: 'Fact hours',
           backgroundColor: 'rgb(127, 137, 138)',
           borderColor: 'rgb(127, 137, 138)',
           data: simpleData[0].hrFact,
        }]
       },
       options: {
                 responsive: true,
                 plugins: {
                      legend: {
                              position: 'top',
                              },
                      title: {
                              display: true,
                              text: 'WorkTS Chart'
                              }
                            }
                          },
                        };                                       
var wotkTSchart = new Chart(
document.getElementById('workTSChart'),
config
);
</script>

Shoejep · Accepted Answer · 2021-07-12 13:04:28Z

1

Your function GetJSON_Simple_workTS is broken, it's missing a ) and it has return resp; as part of the $.ajax request options.

The $.ajax success callback gets called asynchronously, therefore if you're not familiar with async and promises, I would suggest putting your chart creation code in a function and calling that in the success callback, otherwise your GetJSON_Simple_workTS function will return an empty array as it hasn't waited for the response to come back.

answered Jul 12, 2021 at 13:04

Shoejep

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