Change ViewModel default data strictly from server in MVC? - sql

Question

I know this is a weird one but bear with me. I need to set a default state/value for form inputs on a portion of my application.
In my "MainController" I pull up a portion (or 'wrapper' of sorts) page and then pull partial views from this main page. Here's a pseudo-code example:
User goes to Main ->
MainController/Index Called
-> User clicks Link A ->
AJAX .load() pulls html from PartialViewA into #partialContainer
-> User clicks Link B ->
AJAX .load pulls html from PartialViewB into #partialContainer
Here's the AJAX call:
$("#mainPanel").load('#Url.Action("GetModule","Settings")' + '?partialName=' + moduleName);
...and the corresponding server-side action that handles it:
public ActionResult GetModule(string partialName)
{
return PartialView(partialName);
}
It works great for me, each of the modules has plenty of form fields on them, all interacting well with one another and server so that isn't my problem. The issue is setting default values from the dbase for the form fields contained in the partial views.
For instance the "General" partial has many checkboxes which will determine how portions of the application display. I want to pull from the database the pre-exisiting boolean value and when the partial gets pulled from GetModule(), have these values defaulted.
I've taken a look around and I'm afraid the way that I am pulling the partial's into the main page may be the issue. I thought I could build the defaults into the constructor like so:
public class GeneralViewModel
{
public GeneralViewModel()
{
var Data = from m in dataContext.Table
where m.UserID == _id
select new
{
m.Data1,
m.Data2,
};
foreach(var setting in Data)
{
Checkbox1 = Convert.ToBoolean(setting.Data1); // Conversion from bool? to bool
Checkbox2 = Convert.ToBoolean(setting.Data2); // Conversion from bool? to bool
}
}
public bool Checkbox1 { get; set; }
public bool Checkbox2 { get; set; }
}
But it would appear the constructor never gets called. That sort of makes sense, except when you consider the fact that my form fields are not only rendering properly, but communicating with the database just fine as well. So the question is, what am I doing wrong? Is it the way I call the Partial's or am I missing something with assigning values to my VM values?
As always, thanks SO!

Answer 1

I think it's better to have different action methods for rendering the partial views, but for your case, i think this solution would work.
Have a Model that contains the other view models
public class ViewModel
{
public ViewModel1 ViewModel1 { get;set;}
public GenereViewModel General {get;set;}
}
Then in your controller you could initialize the viewmodel based on the partial name.
public ActionResult GetModule(string partialName)
{
var model = new ViewModel();
switch (partialName)
{
case "General": model.General = InitializeGeneral();
break;
case "ViewModel1": model.ViewModel1 = InitializeViewModel1(); break;
}
return PartialView(partialName, model);
}
private GeneralViewModel InitializeGeneral()
{
// initalize then return model
}