In MVC, what is a ViewModel?

Question

Am I right in thinking it\'s almost like a wrapper for all the objects necessary for a View?

For example, say you had an online store that sold music and dvds. On yo

Answer 1

1. ViewModel contain fields that are represented in the view (for LabelFor,EditorFor,DisplayFor helpers)
2. ViewModel can have specific validation rules using data annotations or IDataErrorInfo.
3. ViewModel can have multiple entities or objects from different data models or data source.

Designing ViewModel

public class UserLoginViewModel 
{ 
[Required(ErrorMessage = "Please enter your username")] 
[Display(Name = "User Name")]
[MaxLength(50)]
public string UserName { get; set; }
 [Required(ErrorMessage = "Please enter your password")]
 [Display(Name = "Password")]
 [MaxLength(50)]
 public string Password { get; set; } 
} 

Presenting the viewmodel in the view

@model MyModels.UserLoginViewModel 
@{
 ViewBag.Title = "User Login";
 Layout = "~/Views/Shared/_Layout.cshtml";
}
@using (Html.BeginForm())
{

 @Html.LabelFor(m => m.UserName)


 @Html.TextBoxFor(m => m.UserName)
 @Html.ValidationMessageFor(m => m.UserName)


 @Html.LabelFor(m => m.Password)


 @Html.PasswordFor(m => m.Password)
 @Html.ValidationMessageFor(m => m.Password)