Backend API
        
    import React, { useCallback, useMemo, useState } from 'react';
import SelectBox from 'devextreme-react/select-box';
import { Template } from 'devextreme-react/core/template';
import {
  products,
  simpleProducts,
  simpleProductLabel,
  deferredProductLabel,
  productLabel,
} from './data.ts';
import ImageIcon from './imageIcon.tsx';
import IndicatorIcon from './indicatorIcon.tsx';
import ConditionalIcon from './conditionalIcon.tsx';
import Item from './item.tsx';
function App() {
  const [selectedItem, setSelectedItem] = useState(products[0]);
  const [isLoaded, setIsLoaded] = useState(true);
  const deferredProducts = useMemo<any>(
    () => ({
      loadMode: 'raw',
      load: () => {
        setIsLoaded(false);
        const promise = new Promise((resolve) => {
          setTimeout(() => {
            resolve(simpleProducts);
            setIsLoaded(true);
          }, 3000);
        });
        return promise;
      },
    }),
    [setIsLoaded],
  );
  const renderLoadIndicator = useCallback(
    () => <IndicatorIcon isLoaded={isLoaded} />,
    [isLoaded],
  );
  const renderConditionalIcon = useCallback(
    () => <ConditionalIcon value={selectedItem} />,
    [selectedItem],
  );
  const selectionChanged = useCallback((event: { selectedItem: any }) => {
    setSelectedItem(event.selectedItem);
  }, []);
  return (
    <div className="dx-fieldset">
      <div className="dx-field">
        <div className="dx-field-label">Image as the icon</div>
        <div className="dx-field-value">
          <SelectBox
            dataSource={simpleProducts}
            inputAttr={simpleProductLabel}
            dropDownButtonRender={ImageIcon}
          />
        </div>
      </div>
      <div className="dx-field">
        <div className="dx-field-label">Load indicator as the icon</div>
        <div className="dx-field-value">
          <SelectBox
            dataSource={deferredProducts}
            inputAttr={deferredProductLabel}
            dropDownButtonTemplate="loadIndicator"
          >
            <Template
              name="loadIndicator"
              render={renderLoadIndicator}
            />
          </SelectBox>
        </div>
      </div>
      <div className="dx-field">
        <div className="dx-field-label">Value-dependent icon</div>
        <div className="dx-field-value">
          <SelectBox
            dataSource={products}
            defaultValue={products[0].ID}
            selectedItem={selectedItem}
            displayExpr="Name"
            inputAttr={productLabel}
            showClearButton={true}
            valueExpr="ID"
            itemRender={Item}
            dropDownButtonTemplate="conditionalIcon"
            onSelectionChanged={selectionChanged}
          >
            <Template
              name="conditionalIcon"
              render={renderConditionalIcon}
            />
          </SelectBox>
        </div>
      </div>
    </div>
  );
}
export default App;
    
    import React, { useCallback, useMemo, useState } from 'react';
import SelectBox from 'devextreme-react/select-box';
import { Template } from 'devextreme-react/core/template';
import {
  products,
  simpleProducts,
  simpleProductLabel,
  deferredProductLabel,
  productLabel,
} from './data.js';
import ImageIcon from './imageIcon.js';
import IndicatorIcon from './indicatorIcon.js';
import ConditionalIcon from './conditionalIcon.js';
import Item from './item.js';
function App() {
  const [selectedItem, setSelectedItem] = useState(products[0]);
  const [isLoaded, setIsLoaded] = useState(true);
  const deferredProducts = useMemo(
    () => ({
      loadMode: 'raw',
      load: () => {
        setIsLoaded(false);
        const promise = new Promise((resolve) => {
          setTimeout(() => {
            resolve(simpleProducts);
            setIsLoaded(true);
          }, 3000);
        });
        return promise;
      },
    }),
    [setIsLoaded],
  );
  const renderLoadIndicator = useCallback(() => <IndicatorIcon isLoaded={isLoaded} />, [isLoaded]);
  const renderConditionalIcon = useCallback(
    () => <ConditionalIcon value={selectedItem} />,
    [selectedItem],
  );
  const selectionChanged = useCallback((event) => {
    setSelectedItem(event.selectedItem);
  }, []);
  return (
    <div className="dx-fieldset">
      <div className="dx-field">
        <div className="dx-field-label">Image as the icon</div>
        <div className="dx-field-value">
          <SelectBox
            dataSource={simpleProducts}
            inputAttr={simpleProductLabel}
            dropDownButtonRender={ImageIcon}
          />
        </div>
      </div>
      <div className="dx-field">
        <div className="dx-field-label">Load indicator as the icon</div>
        <div className="dx-field-value">
          <SelectBox
            dataSource={deferredProducts}
            inputAttr={deferredProductLabel}
            dropDownButtonTemplate="loadIndicator"
          >
            <Template
              name="loadIndicator"
              render={renderLoadIndicator}
            />
          </SelectBox>
        </div>
      </div>
      <div className="dx-field">
        <div className="dx-field-label">Value-dependent icon</div>
        <div className="dx-field-value">
          <SelectBox
            dataSource={products}
            defaultValue={products[0].ID}
            selectedItem={selectedItem}
            displayExpr="Name"
            inputAttr={productLabel}
            showClearButton={true}
            valueExpr="ID"
            itemRender={Item}
            dropDownButtonTemplate="conditionalIcon"
            onSelectionChanged={selectionChanged}
          >
            <Template
              name="conditionalIcon"
              render={renderConditionalIcon}
            />
          </SelectBox>
        </div>
      </div>
    </div>
  );
}
export default App;
    
    import React from 'react';
interface ConditionalIconProps {
  value: any;
}
export default function ConditionalIcon({ value }: ConditionalIconProps) {
  if (value) {
    return (
      <img
        alt="Custom icon"
        src={`../../../../images/icons/${value.IconSrc}`}
        className="custom-icon"
      />
    );
  }
  return <div className="dx-dropdowneditor-icon"></div>;
}
    
    import React from 'react';
export default function ImageIcon() {
  return (
    <img
      alt="Custom icon"
      src="../../../../images/icons/custom-dropbutton-icon.svg"
      className="custom-icon"
    />
  );
}
    
    import React from 'react';
import LoadIndicator from 'devextreme-react/load-indicator';
interface IndicatorIconProps {
  isLoaded: any;
}
export default function IndicatorIcon({ isLoaded }: IndicatorIconProps) {
  return (
    <span>
      <LoadIndicator visible={!isLoaded} />
      <span hidden={!isLoaded}>
        <img
          alt="Custom icon"
          src="../../../../images/icons/custom-dropbutton-icon.svg"
          className="custom-icon"
        />
      </span>
    </span>
  );
}
    
    import React from 'react';
export default function Item({ IconSrc, Name }) {
  return (
    <div className="custom-item">
      <img
        alt={Name}
        src={`../../../../images/icons/${IconSrc}`}
      />
      <div className="product-name">{Name}</div>
    </div>
  );
}
    
    import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.tsx';
ReactDOM.render(<App />, document.getElementById('app'));
    
    export const simpleProducts = [
  'HD Video Player',
  'SuperHD Video Player',
  'SuperPlasma 50',
  'SuperLED 50',
  'SuperLED 42',
];
export const products = [{
  ID: 1,
  Name: 'HD Video Player',
  Price: 330,
  Current_Inventory: 225,
  Backorder: 0,
  Manufacturing: 10,
  Category: 'Video Players',
  IconSrc: 'video-player.svg',
}, {
  ID: 2,
  Name: 'SuperHD Player',
  Price: 400,
  Current_Inventory: 150,
  Backorder: 0,
  Manufacturing: 25,
  Category: 'Video Players',
  IconSrc: 'video-player.svg',
}, {
  ID: 3,
  Name: 'SuperPlasma 50',
  Price: 2400,
  Current_Inventory: 0,
  Backorder: 0,
  Manufacturing: 0,
  Category: 'Televisions',
  IconSrc: 'tv.svg',
}, {
  ID: 4,
  Name: 'SuperLED 50',
  Price: 1600,
  Current_Inventory: 77,
  Backorder: 0,
  Manufacturing: 55,
  Category: 'Televisions',
  IconSrc: 'tv.svg',
}, {
  ID: 5,
  Name: 'SuperLED 42',
  Price: 1450,
  Current_Inventory: 445,
  Backorder: 0,
  Manufacturing: 0,
  Category: 'Televisions',
  IconSrc: 'tv.svg',
}];
export const simpleProductLabel = { 'aria-label': 'Simple Product' };
export const deferredProductLabel = { 'aria-label': 'Deferred Product' };
export const productLabel = { 'aria-label': 'Product' };
    
    window.exports = window.exports || {};
window.config = {
  transpiler: 'ts',
  typescriptOptions: {
    module: 'system',
    emitDecoratorMetadata: true,
    experimentalDecorators: true,
    jsx: 'react',
  },
  meta: {
    'react': {
      'esModule': true,
    },
    'typescript': {
      'exports': 'ts',
    },
    'devextreme/time_zone_utils.js': {
      'esModule': true,
    },
    'devextreme/localization.js': {
      'esModule': true,
    },
    'devextreme/viz/palette.js': {
      'esModule': true,
    },
    'openai': {
      'esModule': true,
    },
  },
  paths: {
    'npm:': 'https://cdn.jsdelivr.net/npm/',
    'bundles:': '../../../../bundles/',
    'externals:': '../../../../bundles/externals/',
  },
  defaultExtension: 'js',
  map: {
    'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js',
    'typescript': 'npm:typescript@4.2.4/lib/typescript.js',
    'jszip': 'npm:jszip@3.10.1/dist/jszip.min.js',
    'react': 'npm:react@17.0.2/umd/react.development.js',
    'react-dom': 'npm:react-dom@17.0.2/umd/react-dom.development.js',
    'prop-types': 'npm:prop-types/prop-types.js',
    'rrule': 'npm:rrule@2.6.4/dist/es5/rrule.js',
    'luxon': 'npm:luxon@3.4.4/build/global/luxon.min.js',
    'es6-object-assign': 'npm:es6-object-assign',
    'devextreme': 'npm:devextreme@link:../../packages/devextreme/artifacts/npm/devextreme/cjs',
    'devextreme-react': 'npm:devextreme-react@link:../../packages/devextreme-react/npm/cjs',
    'devextreme-quill': 'npm:devextreme-quill@1.7.6/dist/dx-quill.min.js',
    'devexpress-diagram': 'npm:devexpress-diagram@2.2.24/dist/dx-diagram.js',
    'devexpress-gantt': 'npm:devexpress-gantt@4.1.64/dist/dx-gantt.js',
    'inferno': 'npm:inferno@8.2.3/dist/inferno.min.js',
    'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js',
    'inferno-create-element': 'npm:inferno-create-element@8.2.3/dist/inferno-create-element.min.js',
    'inferno-dom': 'npm:inferno-dom/dist/inferno-dom.min.js',
    'inferno-hydrate': 'npm:inferno-hydrate/dist/inferno-hydrate.min.js',
    'inferno-clone-vnode': 'npm:inferno-clone-vnode/dist/inferno-clone-vnode.min.js',
    'inferno-create-class': 'npm:inferno-create-class/dist/inferno-create-class.min.js',
    'inferno-extras': 'npm:inferno-extras/dist/inferno-extras.min.js',
    '@preact/signals-core': 'npm:@preact/signals-core@1.8.0/dist/signals-core.min.js',
    'devextreme-cldr-data': 'npm:devextreme-cldr-data@1.0.3',
    // SystemJS plugins
    'plugin-babel': 'npm:systemjs-plugin-babel@0.0.25/plugin-babel.js',
    'systemjs-babel-build': 'npm:systemjs-plugin-babel@0.0.25/systemjs-babel-browser.js',
    // Prettier
    'prettier/standalone': 'npm:prettier@2.8.8/standalone.js',
    'prettier/parser-html': 'npm:prettier@2.8.8/parser-html.js',
  },
  packages: {
    'devextreme': {
      defaultExtension: 'js',
    },
    'devextreme-react': {
      main: 'index.js',
    },
    'devextreme-react/common': {
      main: 'index.js',
    },
    'devextreme/events/utils': {
      main: 'index',
    },
    'devextreme/common/core/events/utils': {
      main: 'index',
    },
    'devextreme/localization/messages': {
      format: 'json',
      defaultExtension: 'json',
    },
    'devextreme/events': {
      main: 'index',
    },
    'es6-object-assign': {
      main: './index.js',
      defaultExtension: 'js',
    },
  },
  packageConfigPaths: [
    'npm:@devextreme/*/package.json',
  ],
  babelOptions: {
    sourceMaps: false,
    stage0: true,
    react: true,
  },
};
System.config(window.config);
// eslint-disable-next-line
const useTgzInCSB = ['openai'];
    
    import React from 'react';
export default function ConditionalIcon({ value }) {
  if (value) {
    return (
      <img
        alt="Custom icon"
        src={`../../../../images/icons/${value.IconSrc}`}
        className="custom-icon"
      />
    );
  }
  return <div className="dx-dropdowneditor-icon"></div>;
}
    
    import React from 'react';
export default function ImageIcon() {
  return (
    <img
      alt="Custom icon"
      src="../../../../images/icons/custom-dropbutton-icon.svg"
      className="custom-icon"
    />
  );
}
    
    import React from 'react';
import LoadIndicator from 'devextreme-react/load-indicator';
export default function IndicatorIcon({ isLoaded }) {
  return (
    <span>
      <LoadIndicator visible={!isLoaded} />
      <span hidden={!isLoaded}>
        <img
          alt="Custom icon"
          src="../../../../images/icons/custom-dropbutton-icon.svg"
          className="custom-icon"
        />
      </span>
    </span>
  );
}
    
    import React from 'react';
export default function Item({ IconSrc, Name }) {
  return (
    <div className="custom-item">
      <img
        alt={Name}
        src={`../../../../images/icons/${IconSrc}`}
      />
      <div className="product-name">{Name}</div>
    </div>
  );
}
    
    import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(<App />, document.getElementById('app'));
    
    export const simpleProducts = [
  'HD Video Player',
  'SuperHD Video Player',
  'SuperPlasma 50',
  'SuperLED 50',
  'SuperLED 42',
];
export const products = [
  {
    ID: 1,
    Name: 'HD Video Player',
    Price: 330,
    Current_Inventory: 225,
    Backorder: 0,
    Manufacturing: 10,
    Category: 'Video Players',
    IconSrc: 'video-player.svg',
  },
  {
    ID: 2,
    Name: 'SuperHD Player',
    Price: 400,
    Current_Inventory: 150,
    Backorder: 0,
    Manufacturing: 25,
    Category: 'Video Players',
    IconSrc: 'video-player.svg',
  },
  {
    ID: 3,
    Name: 'SuperPlasma 50',
    Price: 2400,
    Current_Inventory: 0,
    Backorder: 0,
    Manufacturing: 0,
    Category: 'Televisions',
    IconSrc: 'tv.svg',
  },
  {
    ID: 4,
    Name: 'SuperLED 50',
    Price: 1600,
    Current_Inventory: 77,
    Backorder: 0,
    Manufacturing: 55,
    Category: 'Televisions',
    IconSrc: 'tv.svg',
  },
  {
    ID: 5,
    Name: 'SuperLED 42',
    Price: 1450,
    Current_Inventory: 445,
    Backorder: 0,
    Manufacturing: 0,
    Category: 'Televisions',
    IconSrc: 'tv.svg',
  },
];
export const simpleProductLabel = { 'aria-label': 'Simple Product' };
export const deferredProductLabel = { 'aria-label': 'Deferred Product' };
export const productLabel = { 'aria-label': 'Product' };
    
    <!DOCTYPE html>
<html lang="en">
  <head>
    <title>DevExtreme Demo</title>
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" />
    <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/25.1.6/css/dx.light.css" />
    <link rel="stylesheet" type="text/css" href="styles.css" />
    <script src="https://cdn.jsdelivr.net/npm/core-js@2.6.12/client/shim.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/systemjs@0.21.3/dist/system.js"></script>
    <script type="text/javascript" src="config.js"></script>
    <script type="text/javascript">
      System.import("./index.tsx");
    </script>
  </head>
  <body class="dx-viewport">
    <div class="demo-container">
      <div id="app"></div>
    </div>
  </body>
</html>
    
    .dx-dropdowneditor-button .dx-button-content {
  text-align: center;
}
.dx-dropdowneditor-button .dx-button-content .dx-loadindicator {
  width: 1.5em;
  height: 1.5em;
}
.custom-icon {
  max-height: 100%;
  max-width: 100%;
  font-size: 28px;
  display: inline-block;
  vertical-align: middle;
}
.custom-item img {
  float: right;
}
.custom-item .product-name {
  line-height: 32px;
  padding-left: 5px;
}