Handling hidden field in multiple forms in Mvc 4.0 - asp.net-mvc

Question

I am having multiple forms in one page and that page inherits one single model.Every form submission requires a common value. So, common value is stored in hidden field. The hidden field is kept global i.e outside of all the forms but my problem is whenever I submit form, that hidden field is coming to be empty.The hidden field is #Html.HiddenfieldFor(m=>m.FkId) and this FkId is of string type proprty in model i.e public string FkId{get;set;} .Can somebody please guide me how to handle this situation. If I keep hidden field in one of the forms then , it is coming in controller but only for that form submission where I have kept it. But I want that property to be set once and can use in all the form submissions.Please help me. How can I sort out this problem
Some related code
<div id="tabs">
<ul>
<li>Nunc tincidunt</li>
<li>Proin dolor</li>
<li>Aenean lacinia</li>
</ul>
<div id="tabs-1">
#using (Ajax.BeginForm("Evaluation","SaveTab1"{new AjaxOptions { Onsucess= "DisplayMessage" }))
{
#Html.HiddenFieldfor(m=>m.fkID)
<input type="Submit" id="btnTab1" value="Submit" onclick="CheckUser();"/>
}
</div>
<div id="tabs-2">
#using (Ajax.BeginForm("Evaluation","SaveTab2"{new AjaxOptions { Onsucess= "DisplayMessage" }))
{
#Html.HiddenFieldfor(m=>m.fkID)
<input type="Submit" id="btnTab2" value="Submit" />
}
</div>
<div id="tabs-3">
#using (Ajax.BeginForm("Evaluation","SaveTab3"{new AjaxOptions { Onsucess= "DisplayMessage" }))
{
#Html.HiddenFieldfor(m=>m.fkID)
<input type="Submit" id="btnTab3" value="Submit" />
}
</div>
</div>
<script type="text/javascript">
function DisplayMessage(Json)
{
alert( $("#fkID").val(Json.hdn));
// and Alert is showing the value
$("#fkID").val(Json.hdn);
}
</script>
In the Controller I have:
public ActionResult SaveTab1(Model obj)
{
tbl ob =new tbl();
ob.FkId=Obj.fkID;
// after saving, I return
return json(new{hdn=Obj.fkID})
}
public ActionResult SaveTab2(Model obj)
{
tbl ob =new tbl();
ob.FkId=Obj.fkID;
//after saving, I return
return json(new{hdn=Obj.fkID})
}
Similar for tab three, but unfortunately the hidden filed only comes for first form submit. Then I return value to view by json and again set the hidden field property but then it comes null for second form.Please help

Answer 1

First of all, your View does not inherit the Model, it is strongly-typed to the type of your Model. These two are completely different.
But, to answer your question, there's no such a thing as a global hidden field. Fields are not variables. If you want a field to be posted to your Controller, you need to put it inside the form. If you have multiple forms in your View, then you'll have to put the same hidden field inside all the those forms. So, you need to put #Html.HiddenFor(m => m.FkId) inside all the forms in your View.
UPDATE: By the way, it's not Html.HiddenFieldFor, it's Html.HiddenFor.

Answer 2

I have solved the problem. Instead of taking same field in all the forms which was not working, I have taken a unique and different Hidden field properties and after on seperated success function of each form and set the every hidden field a value in success method.