1. 在您的 Angular 项目中安装 CKEditor 5 和自定义插件。您可以使用以下命令进行安装：

npm install --save @ckeditor/ckeditor5-build-classic
npm install --save @ckeditor/ckeditor5-angular
npm install --save ckeditor5-custom-class

2. 在您的组件中导入和定义您的 CKEditor 编辑器：

import ClassicEditor from '@ckeditor/ckeditor5-build-classic';
import { CustomClassPlugin } from 'ckeditor5-custom-class';

@Component({
  selector: 'app-editor',
  template: ''
})
export class EditorComponent {
  public Editor = ClassicEditor;
  public config = {
    plugins: [ CustomClassPlugin ],
    toolbar: [ 'customClass' ]
  };

  // ... your event handlers
}

3. 在您的编辑器工具栏中添加自定义类的按钮。您可以使用 customClass 工具栏按钮来启用自定义类插件：

public config = {
  plugins: [ CustomClassPlugin ],
  toolbar: [ 'customClass' ]
};

4. 在点击自定义类按钮时动态给选中内容添加自定义类。您可以在 CustomClassPlugin 中添加代码以在按钮点击时应用自定义类：

import Plugin from '@ckeditor/ckeditor5-core/src/plugin';

export class CustomClassEditing extends Plugin {
  static get requires() {
    return [ CustomClassUI ];
  }

  init() {
    const editor = this.editor;

    editor.editing.view.document.on( 'click', ( evt, data ) => {
      const target = evt.target;

      if ( target.is( 'element' ) ) {
        const ui = editor.plugins.get( CustomClassUI );
        ui.selectClass( target );
      }
    } );
  }
}

export class CustomClassUI extends Plugin {
  static get pluginName() {
    return 'CustomClassUI';
  }

  init() {
    const editor = this.editor;

    editor.ui.componentFactory.add( 'customClass', locale => {