在ASP.Net Core应用程序中使用Angular作为前端框架，可能会遇到在IFRAMES中嵌入Angular组件或页面时，由于Antiforgery令牌不匹配而出现错误的情况。

为了解决这个问题，需要在后端控制器的ActionResult中包含Antiforgery令牌，并在前端Angular组件中注入Antiforgery令牌。

后端代码示例：

[HttpPost]
[ValidateAntiForgeryToken]
public async Task CreateItem(Item item)
{
    if (ModelState.IsValid)
    {
        // process the data
        return RedirectToAction("Index");
    }
    // if the data is invalid, return to the same page with the same Antiforgery token
    var token = await _antiforgery.GetAndStoreTokens(HttpContext);
    ViewData["AntiForgeryToken"] = token;
    return View(item);
}

前端代码示例：

import { Component, Inject } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { DOCUMENT } from '@angular/common';

@Component({
  selector: 'app-create-item',
  templateUrl: './create-item.component.html',
})
export class CreateItemComponent {
  public item: Item;
  public antiforgeryToken: string;

  constructor(
    private http: HttpClient,
    @Inject(DOCUMENT) private document: Document,
    @Inject('BASE_URL') private baseUrl: string,
  ) {}

  ngOnInit() {
    // get the Antiforgery token from the hidden input element in the form
    this.antiforgeryToken = this.document.getElementsByName('__RequestVerificationToken')[0].getAttribute('value');
  }

  createItem() {
    const headers = new HttpHeaders({
      'Content-Type': 'application/json',
      'RequestVerificationToken': this.antiforgeryToken // include the Antiforgery token in the request header
    });
    this.http.post(`${this.baseUrl}api/items`, this.item, { headers }).subscribe(result => {
      // do something
    });
  }
}