Question

两个问题：我正在研究spfx，对于这个特定的示例，我不了解“发送”按钮如何与setComment（）函数关联。我创建了一个“更新”按钮，我想用它来更新刚刚创建的项目。即使我已经将道具传递给它，它也没有执行任何操作（可能不正确！）

对于“更新”按钮，我尝试使用React在JSX中使用onClick传递道具，但这是行不通的。我也尝试过在没有$的情况下执行此操作。我创建了一组单独的函数_readListItem（）和_getListItem（）来帮助我，但不确定如何将它们与_updateListItem（）结合使用，或者不确定是否需要它们。

import { Environment, EnvironmentType, Version } from '@microsoft/sp-core-library';
import { ISPHttpClientOptions, SPHttpClient, SPHttpClientResponse } from '@microsoft/sp-http';
import { escape } from '@microsoft/sp-lodash-subset';
import { BaseClientSideWebPart, IPropertyPaneConfiguration, PropertyPaneTextField } from '@microsoft/sp-webpart-base';
import * as strings from 'FeedbackWebpartWebPartStrings';
import styles from './FeedbackWebpart.module.scss';
import { IFeedbackWebPartProps } from './IFeedbackWebPartProps';
import {ISPListItem} from './ISPListItem';

export default class FeedbackWebpartWebPart extends BaseClientSideWebPart<IFeedbackWebPartProps> {

  public render(): void {
    this._updateListItem = this._updateListItem.bind(this);
    this._readListItem = this._readListItem.bind(this);
    this.domElement.innerHTML = `
    <div>
    <p class='${styles.titleText}'>Job Evaluation Form</p>
    <i class='ms-Icon ms-Icon--NoteForward' aria-hidden='true'></i>
    <p class='${styles.labelText}'>Name</p>
    <input type='text' class='${styles.input}' maxlength='255' placeholder='${escape(this.properties.hintText)}' />
    <br>
    <br>
    <p class='${styles.labelText}'>Job Title</p>
    <input type='text' class='${styles.input}' maxlength='255' placeholder='${escape(this.properties.hintText)}' />
    <br>
    <p class='${styles.successIndicator}'></p>
    <br>
    <br>
    <br>
    <button type='button' class='ms-Button'><span class='ms-Button-label'>Send</span></button>
    <br>
    <br>
    <button type='button' class='ms-Button' onClick='${this._updateListItem}'><span class='ms-Button-label'>Update</span></button>
    </div>`;

 //The binding below allows setComment to be used in the render and outside of it.
    this.setComment = this.setComment.bind(this);
    this._updateListItem = this._updateListItem.bind(this);
    this._readListItem = this._readListItem.bind(this);
    //Grab ALL the <input> elements
    // [0] -  just want the first element
    // cast this generic element to specific type of element (which I know that it is) as the variable is expecting a specific type
    const textInput: HTMLInputElement = this.domElement.getElementsByTagName("INPUT") [0] as HTMLInputElement;

    // setComment is used in an event listener here to be called upon whenever a user types into this input field.
    textInput.addEventListener("keyup", this.setComment);
    this.sendFeedback = this.sendFeedback.bind(this);
    const submitbutton: HTMLButtonElement = this.domElement.getElementsByTagName("BUTTON") [0] as HTMLButtonElement;

    submitbutton.onclick = this.sendFeedback;
    submitbutton.disabled = true;

  }
private _updateListItem(): void {

  const url: string = this.context.pageContext.site.absoluteUrl+"/_api/web/lists/getbytitle('Feedback')/items(1)";
  const itemDefinition : any = {
    "Title" : "Modified title field value!"};
    const headers:any = {
      "X-HTTP-Method":"MERGE",
      "IF-MATCH": "*",
    };
    const spHttpClientOptions: ISPHttpClientOptions = {
      "headers": headers,
      "body": JSON.stringify(itemDefinition)
    };
    this.context.spHttpClient.post(url, SPHttpClient.configurations.v1,spHttpClientOptions)
    .then((response: SPHttpClientResponse) => {
      if (response.status === 204) {
        this._operationResults.innerHTML = "Update: List Item updated successfully.";

      } else {
        this._operationResults.innerHTML = "Update: List Item update failed. " +response.status+" - "+response.statusText;
      }
    });
    }

private sendFeedback(): void {
  this.context.statusRenderer.clearError(this.domElement);
  const paragraphElement: HTMLParagraphElement = this.domElement.getElementsByClassName(styles.successIndicator) [0] as HTMLParagraphElement;
  paragraphElement.innerHTML="";

  if(this._commentText === undefined || this._commentText.length === 0) {
    this.context.statusRenderer.renderError(this.domElement, "Please type in a comment or a suggestion.");
    return;

  }
  if(Environment.type === EnvironmentType.Local) {
    this.context.statusRenderer.renderError(this.domElement, "Feedback can't be saved when running in local workbench");
    return;
  }

  const url: string = this.context.pageContext.site.absoluteUrl+"/_api/web/lists/getbytitle('Feedback')/items";
  const item : any = {
    "Title": this._commentText,
    "URL": window.location.href,
    "JobTitle": this._jobTitle
  };

  const spHttpClientOptions: ISPHttpClientOptions = {
    "body": JSON.stringify(item)
  };

很抱歉，有很多代码，但是我不知道如果我不提供它，您将如何理解我需要知道的内容。

我希望了解单击“发送”按钮的工作方式和“更新”按钮以更新任何更改的项目。

Answer 1

看起来“发送”按钮的onClick事件是用以下代码设置的：

const submitbutton: HTMLButtonElement = this.domElement.getElementsByTagName("BUTTON") [0] as HTMLButtonElement;

submitbutton.onclick = this.sendFeedback;

此处getElementsByTagName（“ BUTTON”）[0]返回在上述HTML中使用创建的第一个元素。

我想采用相同的方法，更新按钮可以这样处理：

const updateButton: HTMLButtonElement = this.domElement.getElementsByTagName("BUTTON") [1] as HTMLButtonElement;

updateButton.onclick = this._updateListItem.bind(this);

请注意将索引从[0]更改为[1]，以使用第二个按钮，以及bind（）的用法。如果没有绑定，则在调用_updateListItem时将无法定义“ this”。

该代码如何将“发送”按钮与该功能相关联，我将如何创建另一个按钮？

1 个答案: