Cannot apply indexing with [] to an expression of type 'HttpRequest' - asp.net-mvc

Question

I am trying to get a value from a textbox of my View.
This is my View:
#model MyDataIndexViewModel
#{
<div class="row">
<div class="col-xs-12 col-sm-12 col-md-12">
<h1>Meine Daten</h1>
</div>
</div>
var item = Model.User;
<div class="row">
<div class="col-xs-6 col-sm-6 col-md-6 myDataTitle">Email</div>
<div class="col-xs-6 col-sm-6 col-md-6">
#Html.TextBox("txtEmail", "", new { placeholder = item.Email})
</div>
</div>
}
<div class="row">
<div class="col-xs-12 col-sm-12 col-md-12">
<a class="btn btn-default pull-right" href="/ChangeMyData/Save">Speichern</a>
</div>
</div>
This is my Controller:
[HttpPost]
public ActionResult Save()
{
var email = Request["txtEmail"].ToString();
return View();
}
I get the error just as it says in the Title.
Thank you in advance!

Answer 1

VIEW:
#model MyDataIndexViewModel
#using (Html.BeginForm("Save", "CONTROLLER_NAME"))
{
<div class="row">
<div class="col-xs-12 col-sm-12 col-md-12">
<h1>Meine Daten</h1>
</div>
</div>
var item = Model.User;
<div class="row">
<div class="col-xs-6 col-sm-6 col-md-6 myDataTitle">Email</div>
<div class="col-xs-6 col-sm-6 col-md-6">
#Html.TextBox("txtEmail", "", new { placeholder = item.Email, id="txtEmail"})
</div>
</div>
<div class="row">
<div class="col-xs-12 col-sm-12 col-md-12">
<a class="submit btn btn-default pull-right">Speichern</a>
</div>
</div>
}
CONTROLLER
[HttpPost]
public ActionResult Save()
{
var email = Request.Form["txtEmail"].ToString();
return View();
}

Answer 2

You can either use strongly-typed viewmodel binding:
View
#model MyDataIndexViewModel
#* other stuff *#
#Html.TextBox("txtEmail", Model.Email)
Controller
[HttpPost]
public ActionResult Save(MyDataIndexViewModel model)
{
var email = model.Email;
return View();
}
Or use a TextBoxFor directly for model binding:
#model MyDataIndexViewModel
#* other stuff *#
#Html.TextBoxFor(model => model.Email)
Or if you still want to use HttpRequest members, Request.Form collection (a NameValueCollection) is available to retrieve text from txtEmail input:
[HttpPost]
public ActionResult Save()
{
var email = Request.Form["txtEmail"].ToString();
return View();
}
Note that Request["txtEmail"] is discouraged due to no compile time safety applied for it, because the key value may retrieved from Request.QueryString, Request.Form or other HttpRequestBase members.
Similar issue:
MVC TextBox with name specified not binding model on post
Access form data into controller using Request in ASP.NET MVC