JavaScript ArcGIS ElementExpressionInfo.expression用法及代码示例

基本信息

以下是所在类或对象的基本信息。

AMD: require(["esri/popup/ElementExpressionInfo"], (ElementExpressionInfo) => { /* code goes here */ });

ESM: import ElementExpressionInfo from "@arcgis/core/popup/ElementExpressionInfo";

类： esri/popup/ElementExpressionInfo

继承: ElementExpressionInfo > Accessor

自从：用于 JavaScript 4.22 的 ArcGIS API

用法说明

ElementExpressionInfo.expression函数(或属性)的定义如下：

expression String

Arcade 表达式计算为字典。字典必须表示 TextContent 、 FieldsContent 或 MediaContent 弹出内容元素，如 Popup Element web map specification 中定义的那样。

此表达式可以使用 $feature 、 $layer 、 $map 和 $datastore 全局变量从Map或数据存储中的要素、其图层或其他图层访问数据值。有关有效返回字典的更多信息和示例，请参阅Popup Element Arcade Profile 规范。

例子：

// Creates an column chart where each category/value
// is an aggregate of two or more fields
layer.popupTemplate = {
  title: "Educational Attainment",
  content: [{
    type: "expression",
    expressionInfo: {
      expression: `
        // Create a dictionary of attributes representing the values
        // to display in the table
        var attributes = {
          "No School": $feature.no_school + $feature.some_primary,
          "Primary": $feature.primary_complete + $feature.some_secondary,
          "Secondary": $feature.secondary_complete + $feature.some_highSchool,
          "High School": $feature.highSchool_diploma + $feature.highSchool_ged + $feature.some_college,
          "College/University": $feature.associates + $feature.bachelors + $feature.masters + $feature.doctorate + $feature.professional;
        };

        var fieldInfos = [];

        // Create an array representing the attribute names (or keys)
        // to include in the chart
        for (var k in attributes){
          Push(fieldInfos, {
            fieldName: k
          });
        }

        // Returns a dictionary providing the information
        // required by the popup to render a table of key value pairs
        return {
          type: "media",
          attributes: attributes,
          // The list of attribute names (keys) to include in the table
          fieldInfos: fieldInfos
        };
      `,
      title: "Educational Attainment"
    }
  }]
};

相关用法

注：本文由纯净天空筛选整理自arcgis.com大神的英文原创作品 ElementExpressionInfo.expression。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。