如何在Angular中发表表格帖子？

Question

payment.php

<p>Redirecting...</p>
<form action="https://biz.traknpay.in/v2/paymentrequest" id="payment_form" method="POST">
<input type="hidden" value="<?php echo $hash; ?>"                   name="hash"/>
<input type="hidden" value="<?php echo $_POST['api_key'];?>"        
name="api_key"/>
<input type="hidden" value="<?php echo $_POST['return_url']; ?>"    name="return_url"/>
<input type="hidden" value="<?php echo $_POST['mode'];?>"           name="mode"/>
<input type="hidden" value="<?php echo $_POST['order_id'];?>"       name="order_id"/>
<input type="hidden" value="<?php echo $_POST['amount'];?>"         name="amount"/>
<input type="hidden" value="<?php echo $_POST['currency'];?>"       name="currency"/>
<input type="hidden" value="<?php echo $_POST['description'];?>"    name="description"/>
<input type="hidden" value="<?php echo $_POST['name'];?>"           name="name"/>
<input type="hidden" value="<?php echo $_POST['email'];?>"          name="email"/>
<input type="hidden" value="<?php echo $_POST['phone'];?>"          name="phone"/>
<input type="hidden" value="<?php echo $_POST['city'];?>"           name="city"/>
<input type="hidden" value="<?php echo $_POST['state'];?>"          name="state"/>
<input type="hidden" value="<?php echo $_POST['zip_code'];?>"       name="zip_code"/>
<input type="hidden" value="<?php echo $_POST['country'];?>"        name="country"/>

<noscript><input type="submit" value="Continue"/></noscript>
</form>
<script>
 function formAutoSubmit () {
 var payform = document.getElementById("payment_form");
 payform.submit();
  }
 window.onload = formAutoSubmit;
 </script>

以下是代码将页面重定向到带有参数的支付网关页面。我试图在角度代码中实现相同的功能，但它不再起作用。将支付请求页面的模板作为响应体。

payment.ts

payment(){
let paymentdata = new FormData();
paymentdata.append('api_key', '69563fbfa-939a-4356d8-92567c-fd2d6e560fa72f');
paymentdata.append('order_id', '11111111111124');
paymentdata.append('mode', 'TEST');
paymentdata.append('amount', '200');
paymentdata.append('currency', 'INR');
paymentdata.append('description', 'BLABLA');
paymentdata.append('name', 'Ajith');
paymentdata.append('email', 'ajith@gmail.com');
paymentdata.append('phone', '8086502009');
paymentdata.append('city', 'tvm');
paymentdata.append('country', 'IND');
paymentdata.append('zip_code', '695505');
paymentdata.append('return_url', 'http://localhost:8100/#/payment/paymentrequest');
paymentdata.append('hash', '8A9DBABCF0CBB9618F74DEA95982DD5D710347B643F45A1E1DFFA42941EACB77C9F8D5C79F7D2EF8FDDFCD944E7EDE36F5D2FF8FBC5D0822A2C79CBDCE73DE05');

  console.log(paymentdata)
  return this.http.post('https://biz.traknpay.in/v2/paymentrequest',paymentdata).map(res=>res).subscribe(res=>
{
  window.open("https://biz.traknpay.in/v2/paymentrequest", "_blank");
  this.body=res;
  console.log(this.body)
   },
err=>{
console.log(err)
})

 }