When should I use ViewBag/model?

Question

I think that using ViewBag is faster than model.

My example is:

In the action:

public ActionResult MyAction()
{
   ViewBag.Data = (from m in myDatabase.myTable select m).ToList();
}

In the view:

@foreach(var item in ViewBag.Data)
{
   <tr>
      <td>@item.myColumn</td>
   </tr>
}

By using model:

[Table("tbl_mytable")]
public class MyTable()
{
   public int Id { get; set; }
   public int Column2 { get; set; }
   public int Column3 { get; set; }
   // ...
   public IEnumerable<MyTable> Data { get; set; }
}

in the model:

public class MainClass
{
   public List<MyTable> MyMethod()
   {
      List<MyTable> list = new List<MyTable>();
      // code logic to find data in database and add to list
      list.Add(new MyTable
      {
         Column2 = ...
         Column3 = ...
      });
      return list;
   }
}

in the action:

public ActionResult MyAction()
{
   MainClass mc = new MainClass();
   MyTable model = new MyTable();
   model.Data = mc.MyMethod();
   return View(model);
}

in the view:

@using MyProjectName.Models
@model MyProjectName.Models.MyTable

@foreach(MyTable item in Model.Data)
{
   <tr>
      <td>@item.Column1</td>
   </tr>
}

Both of them are working, and ViewBag is easier than model.

So, can you tell me: When should I use ViewBag/model?

possible duplicate of [ViewBag vs Model, in MVC.NET](http://stackoverflow.com/questions/21716953/viewbag-vs-model-in-mvc-net) — user2609980, Jun 13 '15 at 16:10

score 0 · Answer 1 · answered Jun 13 '15 at 17:01

0

use model if you want strongly-typed add Messages to your View Model. Otherwise, stick with ViewBag.

answered Jun 13 '15 at 17:01

MMM

3,132
3
20
32

score 0 · Accepted Answer · 2015-06-14T00:43:42.423

0

ViewBag is not faster. In both cases your creating a model of List<MyTable>. All the code you have show for creating your 'MyTable' model is pointless - your just creating a new collection containing duplicates from the existing collection. In the controller it just needs to be

public ActionResult MyAction()
{
  var model = (from m in myDatabase.myTable select m).ToList();
  return View(model);
}

and in the view

@model List<MyProjectName.Models.MyTable> // a using statement is not required when you use the fully qualified name
@foreach(var item in Model)
{
  <tr>
    <td>@item.myColumn</td>
  </tr>
}

And your MyTable model should not have a property public IEnumerable<MyTable> Data { get; set; } unless your creating a hierarchical model.

Always use models (preferably view model) in you view so you can take advantage of strong typing (vs ViewBag which is dynamic)

edited Jun 14 '15 at 00:43

answered Jun 14 '15 at 00:35

Thanks. Can you tell me little more? In your example, if I want to call more than 1 table in database, like: `var model1 = (from m in myDatabase.myTable1 select m).ToList();` and `var model2 = (from n in myDatabase.myTable2 select n).ToList();` return where? `return (???)` – Jun 14 '15 at 03:58
I mean that using ViewBag is easier, just like: `ViewBag.Model1 = (from m in myDatabase.myTable1 select m).ToList();` and `ViewBag.Model2 = (from n in myDatabase.myTable2 select n).ToList();` – Jun 14 '15 at 04:03
1

Then the correct approach is to use a view model. It could contain 2 properties `List Table1 { get; set; }` and `List Table2 { get; set; }` and then in the view, `var model = new MyViewModel() { Table1 = (from m in myDatabase.myTable1 select m).ToList(), Table2 = (from n in myDatabase.myTable2 select n).ToList(); };` and return the model to the view. – Jun 14 '15 at 04:10

When should I use ViewBag/model?

2 Answers2