Generating a dropdown list with database first - asp.net

Question

In my mvc3 application i want to populate the dropdownlist for the data which is coming from database here am using entityframework with database first approach so please help me to do this

Answer 1

You did not provide any code of what you have done so far so I know nothing about the data that you have been working with. I will post some code and all that you will have to do is to modify it to fit in with your scenario.
Lets work with a simple solution of loan applications. A client needs to apply for a loan and he needs to supply banking details. He will have to select a bank from a drop down list.
Lets start with the domain model called Bank. This represents your data coming from your database table. Lets call the table Banks.
public class Bank
{
public int Id { get; set; }
public string Name { get; set; }
}
Your table called Banks will look like this:
Id | int | not null | primary key
Name | varchar(50) | not null
Depeneding on you what you need to do I normally have a service layer that calls my bank repository to bring back the data. But seeing that you only need to bring back data and nothing else we can skip the service layer.
public class BankRepository : RepositoryBase<Bank>, IBankRepository
{
public IEnumerable<Bank> FindAll()
{
return DatabaseContext.Banks;
}
}
You database context will look like this:
public class DatabaseContext : DbContext
{
public DbSet<Bank> Banks { get; set; }
}
This is how your data retrieval methods could look like. It might not be the full solution but there are many samples online. Just go and Google.
Lets move onto the web application.
Your view/page will work with a view model and not your domain model. You use view models to represent your data on the view/page. So on your create view you will pass in a create application view model with a list of your banks. An instance of IBankRepository will be supplied through a technique called dependency injection. I use Autofac for this.
public class ApplicationViewModel
{
public int BankId { get; set; }
public IEnumerable<Bank> Banks { get; set; }
}
Your controller's action method will populate the view model and send it to your view.
public class ApplicationController : Controller
{
private readonly IBankRepository bankRepository;
public ApplicationController(IBankRepository bankRepository)
{
this.bankRepository = bankRepository;
}
public ActionResult Create()
{
ApplicationViewModel viewModel = new ApplicationViewModel
{
Banks = bankRepository.FindAll()
};
return View(viewModel);
}
}
Your view will then receive this view model and do with it what it needs to do. In this case it will populate your bank drop down.
#model YourProject.ViewModels.Applications.ApplicationViewModel
#using (Html.BeginForm())
{
<tr>
<td class="edit-label">Bank: <span class="required">**</span></td>
<td>
#Html.DropDownListFor(
x => x.BankId,
new SelectList(Model.Banks, "Id", "Name", Model.BankId),
"-- Select --"
)
#Html.ValidationMessageFor(x => x.BankId)
</td>
</tr>
}
I don't what your experience is but judging from your question it seems like you still need to do a lot of research. There are tonnes of examples online. You will need to work through samples of Entity Framework code first and ASP.NET MVC. Invest some time and you will reap the rewards later.
I hope this works and best of luck. The solution might not be what you want but it can help guide you in the right direction.

Answer 2

Let assume you have a class like so
public class ProductBrand
{
//Eg. Nokia, Hp, Dell
/// <summary>
/// Second Level to Category
/// Has Foreign Key to category table
/// </summary>
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ProductBrandId { get; set; }
[Display(Name = "Category")]
public int ProductCategoryId { get; set; }
public virtual ProductCategory ProductCategory { get; set; }
[Required(ErrorMessage = "This field is required")]
[StringLength(300, ErrorMessage = "This field must not be greater than 300 xters long")]
[Display(Name="Name")]
public string BrandName { get; set; }
public IList<Product> Products { get; set; }
[Display(Name = "Status")]
public bool ActiveStatus { get; set; }
}
Which means this model has a foreign key name ProductCategoryId then in your create Product brand view you will need a dropdownlist containing All productcategory to choose from.
Just create an actionresult like so
public ActionResult CreateProductBrand() {
ViewBag.ProductCategoryId = new SelectList(context.ProductCategories, "ProductCategoryId", "CategoryName");
return View();
}
Then call the viewbag in you corrensponding view like so:
#using (Html.BeginForm()) {
#Html.AntiForgeryToken()
#Html.ValidationSummary(true)
<table style="width:400px" class="post-form">
<tr>
<td>Category</td>
<td>
<div class="editor-field">
#Html.DropDownList("ProductCategoryId", String.Empty)
#Html.ValidationMessageFor(model => model.ProductCategoryId)
</div>
</td>
</tr>
</table>
<table style="width:400px" class="post-form">
<tr>
<td>Brand</td>
<td>
<div class="editor-field">
#Html.EditorFor(model => model.BrandName)
#Html.ValidationMessageFor(model => model.BrandName)
</div>
</td>
</tr>
<tr>
<td>Status</td>
<td>
<div class="editor-field">
#Html.EditorFor(model => model.ActiveStatus)
#Html.ValidationMessageFor(model => model.ActiveStatus)
</div>
</td>
</tr>
<tr>
<td></td>
<td>
<input type="submit" class="button blue" value="Save" />
<a href="#Url.Action("ProductBrand", "ProductSetup")" class="button">Cancel
</a>
</td>
</tr>
</table>
}

Answer 3

ViewModel:
public List<Item> _Items { get; set; }
public int_newID { get; set; }
Model Item
public int_id { get; set; }
public string _name { get; set; }
Controller:
Populate _Items with data and send that list to your view
View:
#Html.DropDownListFor(c => c._newID, new SelectList(Model._Items , "_id", "_name"),--Select Item--")