当日期值为 null 时，在 HTML 页面中显示自定义文本

Question

I have a Gantt Chart which is used to show the Project Timeline.我有一个甘特图，用于显示项目时间表。 I am using Google Charts to display the Gantt Chart.我正在使用 Google Charts 来显示甘特图。

I am using this Gantt chart in VisualForce page to get the date values from Salesforce.我在 VisualForce 页面中使用此甘特图从 Salesforce 获取日期值。

Below is my logic:以下是我的逻辑：

<apex:page standardController="Project__c">
    <apex:form >
 <html>
<head>
  <script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
  <script type="text/javascript">
    google.charts.load('current', {'packages':['gantt']});
    google.charts.setOnLoadCallback(drawChart);

    function drawChart() {

      var data = new google.visualization.DataTable();
      data.addColumn('string', 'Task ID');
      data.addColumn('string', 'Task Name');
      data.addColumn('date', 'Start Date');
      data.addColumn('date', 'End Date');
      data.addColumn('number', 'Duration');
      data.addColumn('number', 'Percent Complete');
      data.addColumn('string', 'Dependencies');

      data.addRows([
        ['Research', 'Find sources',
         new Date("{!Project__c.GLI_Planned_Date__c}"), new Date("{!Project__c.GLI_Actual_Date__c}"), null,  100,  null],
        ['Write', 'Write paper',
         new Date("{!Project__c.REG_Planned_Date__c}"), new Date("{!Project__c.REG_Actual_Date__c}"), daysToMilliseconds(3), 25, 'null'],
        ['Cite', 'Create bibliography',
         new Date("{!Project__c.UAT_Planned_Date__c}"), new Date("{!Project__c.UAT_Actual_Date__c}"), daysToMilliseconds(1), 20, 'null'],
        ['Complete', 'Hand in paper',
         new Date("{!Project__c.STP_Planned_Date__c}"), new Date("{!Project__c.STP_Actual_Date__c}"), daysToMilliseconds(1), 0, 'null'],
        ['Outline', 'Outline paper',
         new Date("{!Project__c.ARC_Planned_Date__c}"), new Date("{!Project__c.ARC_Actual_Date__c}"), daysToMilliseconds(1), 100, 'null']
      ]);

      var options = {
        height: 400,
        gantt: {
          trackHeight: 30
        }
      };

      var chart = new google.visualization.Gantt(document.getElementById('chart_div'));

      chart.draw(data, options);
    }
  </script>
</head>
<body>
  <div id="chart_div"></div>
</body>
</html>
</apex:form>
</apex:page>

For few records, the date fields are null.对于少数记录，日期字段为 null。 Due to that, I am seeing the error因此，我看到了错误

Cannot read property 'datefield' of undefined无法读取未定义的属性“日期字段”

Is there any way that I can display some custom banner like "Required date values are not available" instead of the above error in case of missing date values?有什么方法可以显示一些自定义横幅，例如“所需的日期值不可用”，而不是在缺少日期值的情况下出现上述错误？

Answer 1

You have to validate the datefield if it is undefined, for example如果日期字段未定义，您必须验证它，例如

var datefield = (typeof !== 'undefined') ? datefield : 'some default value';

当日期值为 null 时，在 HTML 页面中显示自定义文本

问题描述

1 个解决方案

解决方案1
0 2021-06-13 14:03:11

当日期值为 null 时，在 HTML 页面中显示自定义文本

问题描述

1 个解决方案

解决方案1 0 2021-06-13 14:03:11

解决方案1
0 2021-06-13 14:03:11