Question

Say I have the following form that’s in classic asp:

<form name="impdata" id="impdata" method="POST" action="http://www.bob.com/dologin.asp">
<input type="hidden" value="" id="txtName" name="txtName" />
</form>

I need to simulate the action of submitting the form in asp.net mvc3, but I need to modify the hidden value before submitting. Is it possible to do this from the action or in another way?

What I have so far…

View:

@using (Html.BeginForm("Impersonate", "Index", FormMethod.Post, new { id = "impersonateForm" }))
{                       
    <input id="Impersonate" class="button" type="submit" value="Impersonate" action />
    <input type="hidden" value="" id="txtName" name="txtName" />
}

Controller:

[HttpPost]
public ActionResult Impersonate(string txtName)
{
txtName = txtName + "this string needs to be modified and then submitted as a hidden field";  
//Redirect won't work needs the hidden field
//return Redirect("http://www.bob.com/dologin.asp");
}

Solution:

Seems that it isn’t easy to do this from the controller so I ended up using jQuery. The action returns a JsonResult.
Something like:

<button id="Impersonate" class="button" onclick="Impersonate()">Impersonate!</button>

<form name="impdata" id="impersonateForm" action="http://www.bob.com/dologin.asp">
  <input type="hidden" value="" id="txtName" name="txtName" /> 
</form>

function Impersonate() {           
    $.ajax({
        type: 'POST',
        asynch: false,
        url: '@Url.Action("Impersonate", "Index")',
        data:
            {
                name: $('#txtName').val()                    
            },
        success: function (data) {                
            $('#txtName').val(data.Name);              
            $('#impersonateForm').submit();               
        }
    });

Seems to work well…

Answer 1

It is rather hard to redirect to a POST from a POST (relies on HTTP status codes without universal support), and it is impossible from a GET.

The simplest solution is probably a little JavaScript on the result that posts the (new) form.

Thus you action method returns a view with the necessary data in it (passed via the model from the controller) which will include the JavaScript.