ASP.NET MVC, passing Model from View to Controller - asp.net-mvc

Question

I'm having trouble with ASP.NET MVC and passing data from View to Controller. I have a model like this:
public class InputModel {
public List<Process> axProc { get; set; }
public string ToJson() {
return new JavaScriptSerializer().Serialize(this);
}
}
public class Process {
public string name { get; set; }
public string value { get; set; }
}
I create this InputModel in my Controller and pass it to the View:
public ActionResult Input() {
if (Session["InputModel"] == null)
Session["InputModel"] = loadInputModel();
return View(Session["InputModel"]);
}
In my Input.cshtml file I then have some code to generate the input form:
#model PROJ.Models.InputModel
#using(Html.BeginForm()) {
foreach(PROJ.Models.Process p in Model.axProc){
<input type="text" />
#* #Html.TextBoxFor(?? => p.value) *#
}
<input type="submit" value="SEND" />
}
Now when I click on the submit button, I want to work with the data that was put into the textfields.
QUESTION 1: I have seen this #Html.TextBoxFor(), but I don't really get this "stuff => otherstuff". I concluded that the "otherstuff" should be the field where I want to have my data written to, in this case it would probably be "p.value". But what is the "stuff" thing in front of the arrow?
Back in the Controller I then have a function for the POST with some debug:
[HttpPost]
public ActionResult Input(InputModel m) {
DEBUG(m.ToJson());
DEBUG("COUNT: " + m.axProc.Count);
return View(m);
}
Here the Debug only shows something like:
{"axProc":[]}
COUNT: 0
So the returned Model I get is empty.
QUESTION 2: Am I doing something fundamentally wrong with this #using(Html.BeginForm())? Is this not the correct choice here? If so, how do I get my model filled with data back to the controller?
(I cannot use "#model List< Process >" here (because the example above is abbreviated, in the actual code there would be more stuff).)
I hope someone can fill me in with some of the details I'm overlooking.

Answer 1

Change your view to some thing like this to properly bind the list on form submission.
#using(Html.BeginForm()) {
for(int i=0;i<Model.axProc.Count;i++){
<span>
#Html.TextBoxFor(model => model.axProc[i].value)
</span>
}
<input type="submit" value="SEND" />
}

Answer 2

In #Html.TextBoxFor(stuff => otherstuff) stuff is your View's model, otherstuff is your model's public member.
Since in the View you want to render input elements for the model member of a collection type (List), you should first create a separate partial view for rendering a single item of that collection (Process). It would look something like this (name it Process.cshtml, for example, and place into the /Views/Shared folder):
#model List<PROJ.Models.Process>
#Html.TextBoxFor(model => p.value)
Then, your main View would look like this:
#model PROJ.Models.InputModel
#using(Html.BeginForm()) {
foreach(PROJ.Models.Process p in Model.axProc){
#Html.Partial("Process", p)
}
<input type="submit" value="SEND" />
}
Also, check that the loadInputModel() method actually returns something, e.g. not an empty list.