Question

我称我为查看器对象，该对象将某些东西装入ID为tgmlviewer的元素中。当我只有一个这样的组件时，这可以很好地工作。

import React, { useEffect } from "react";
import { Viewer } from "../../tgmlViewer/Viewer";
import { disableTgmlPointerEvents } from "../../../constants";
import { XmlType } from "./XmlView";

type Props = {
  serialized: string;
  xmlType: XmlType;
};

const tgmlViewerId = "tgmlviewer";

export default function TgmlImageViewer(props: Props) {
  const { serialized, xmlType } = props;

  useEffect(() => {
    let viewer: Viewer;
    const viewerElement = document.getElementById(tgmlViewerId);
    if (viewerElement instanceof HTMLDivElement) {
      viewer = new Viewer(viewerElement);
      viewer.load(serialized);
    }
    return () => {
      if (viewer) {
        viewer.reset();
      }
    };
  });

  return (
    <div
      id={tgmlViewerId}
    />
  );
}

现在，我想创建多个组件。每个组件都需要向其查看器对象传递唯一的ID。可以使用useRef吗？

这是我的最佳尝试：

import React, { useEffect, useRef, Ref } from "react";
import { Viewer } from "../../tgmlViewer/Viewer";
import { disableTgmlPointerEvents } from "../../../constants";
import { XmlType } from "./XmlView";

type Props = {
  serialized: string;
  xmlType: XmlType;
};

export default function TgmlImageViewer(props: Props) {
  const { serialized, xmlType } = props;

  const tgmlViewerMountingTarget = useRef(null);

  useEffect(() => {
    if (!tgmlViewerMountingTarget) {
      return;
    }
    let viewer: Viewer;
    const viewerElement = tgmlViewerMountingTarget.current;
    if (viewerElement instanceof HTMLDivElement) {
      viewer = new Viewer(viewerElement);
      viewer.load(serialized);
    }
    return () => {
      if (viewer) {
        viewer.reset();
      }
    };
  });

  return (
    <div
      ref={tgmlViewerMountingTarget}
    />
  );
}

TypeScript错误

ts：const viewerElement：null //“ instanceof”表达式的左侧必须为“ any”类型，对象类型或类型参数。

Answer 1

更改

const tgmlViewerMountingTarget = useRef(null);

到

const tgmlViewerMountingTarget = useRef<HTMLDivElement>(null);

我可以使用useRef将对元素的引用传递给孩子吗？

1 个答案: