How to pass data to the view in mvc asp.net? - asp.net-mvc

Question

let me ask the question first.
Where is the correct place to call a function that load a list of values to be display on a view?
I create a controller like this
public ActionResult Create()
{
SeaModel newSea = new SeaModel();
return View("Season/CreateSea", newSea);
}
//I not quite sure if this should go here or in another place
partial class seaDataContext
{
public List<string> getSeaSettings()
{
var seaSettings = from p in settings
where p.setting == "periods"
select p.value;
return seaSettings.ToList<string>();
}
}
The model is like
public class SeaModel
{
[Required(ErrorMessage="*")]
[Display(Name = "Period Name")]
public string periods { get; set; }
}
Which create a view like
#using (Html.BeginForm()) {
#Html.ValidationSummary(true, "Please correct the following errors.")
<fieldset>
<legend>Fields</legend>
<div class="editor-label">
#Html.LabelFor(model => model.periods)
</div>
<div class="editor-field">
#Html.Select(model => model.periods, ****My doubt comes here****)
#Html.ValidationMessageFor(model => model.periods)
</div>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
}
so, How and where do I pass the return of getSeaSettings() to the view?
Thanks

Answer 1

best practice is to make a Selectlist in your Model for this dropdown.
however you also can use the more easy option: using ViewData
public ActionResult Create()
{
SeaModel newSea = new SeaModel();
ViewData["myDropDown"] = new SelectList(listOfObjects, "valueOfTheObjectLikeID", "NameYouWantToShowInDropdown");
return View("Season/CreateSea", newSea);
}
then:
#Html.Select(model => model.periods, ViewData["myDropDown"] as SelectList)
dont forget in your [HttpPost] method to also fill in the viewdata if you'r validation fails, so the dropdown can be rebuilt.

Answer 2

You need to look at repository pattern. Have a look at this tutorial at asp.net site
http://www.asp.net/mvc/tutorials/creating-model-classes-with-linq-to-sql-cs

Answer 3

Stefanvds's approach was what I used to do.
But I found out there is a better way using additionalViewData.
Use this EditorFor HTML Helper extension method.
http://msdn.microsoft.com/en-us/library/ff406462.aspx
Instead of passing Select List Items into ViewData in the Controller, you do this in your View.
Pass in your list items as an anonymous object for the additionalViewData parameter.
Important thing is to use the same name as your Property Name.
#Html.EditorFor(
m => m.MyPropertyName,
new { MyPropertyName = Model.ListItemsForMyPropertyName }
);
Of course, you are passing in a View Model object.
public class MyViewModel
{
public int MyPropertyName;
public IList<SelectListItem> ListItemsForMyPropertyName;
}
EditorFor method uses your existing Editor View Templates.
So you don't need to specify CSS class names and HTML attributes again like when you use the Html.DropDown( ) method.
For example,
//------------------------------
// additionalViewData
//------------------------------
#Html.EditorFor(
m => m.MyPropertyName,
new { MyPropertyName = Model.ListItemsForMyPropertyName }
)
//------------------------------
// traditional approach requires to pass your own HTML attributes
//------------------------------
#Html.DropDown(
"MyPropertyName",
Model.ListItemsForMyPropertyName,
new Dictionary<string, object> {
{ "class", "myDropDownCssClass" }
}
);
//------------------------------
// DropDownListFor still requires you to pass in your own HTML attributes
//------------------------------
#Html.DropDownListFor(
m => m.MyPropertyName,
Model.ListItemsForMyPropertyName,
new Dictionary<string, object> {
{ "class", "myDropDownCssClass" }
}
);
That is why I like the additionalViewData approach more.
Because, the HTML code rendered relies on the Editor Templates completely.
Also, using specialized View Models make your code cleaner and easier to maintain.
Hope it helps.