How to Create Drop-Down-List from Database in (Asp.net Core - MVC)? - drop-down-menu

Question

I have 2 models:
News Model
TypeOfNew Model
with (one to many relationship), every (TypeOfNew) has one or multiple news.
News Model:
public class News
{
[Required(ErrorMessage = "ID إجباري.")]
[Key]
public int ID { get; set; }
[Required(ErrorMessage = "الحقل إجباري.")]
[Display(Name = "عنوان الخبر")]
public string Title { get; set; }
[Required(ErrorMessage = "الحقل إجباري.")]
[Display(Name = "مصدر الخبر")]
public string Source { get; set; }
[Required(ErrorMessage = "الحقل إجباري.")]
[Display(Name = "الوصف")]
[MaxLength(5000)]
public string Description { set; get; }
[Display(Name = "نوع الخبر")]
public int NewsTypeId { set; get; }
public TypeOfNew TypeOfNew { set; get; }
}
TypeOfNew Model:
public class TypeOfNew
{
[Key]
public int TypeId { set; get; }
[Display(Name = " نوع الخبر")]
public string TypeName { set; get; }
public ICollection<News> News { get; set; }
}
in Create View(News), I want to display drop-down-list of (TypeOfNew).
so when I post (Create View) I want to store (TypeId) of (TypeOfNew model) in (NewsTypeId) of (News model).
So, what should I do in:
create Action (Get).
create Action (Post).
Create View.

Answer 1

Assume that you have set below tables in dbcontext:
public DbSet<News> News { get; set; }
public DbSet<TypeOfNew> TypeOfNews { get; set; }`
You could refer to below steps to achieve your requirements:
1.Create action GET
public IActionResult Create()
{
ViewData["NewsTypeId"] = new SelectList(_context.TypeOfNews, "TypeId", "TypeName");
return View();
}
2.Create action POST
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create([Bind("ID,Title,Source,Description,NewsTypeId")] News news)
{
if (ModelState.IsValid)
{
_context.Add(news);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
ViewData["NewsTypeId"] = new SelectList(_context.TypeOfNews, "TypeId", "TypeName", news.NewsTypeId);
return View(news);
}
3.Create View
#model News
<h1>Create</h1>
<hr />
<div class="row">
<div class="col-md-4">
<form asp-action="Create">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group">
<label asp-for="Title" class="control-label"></label>
<input asp-for="Title" class="form-control" />
<span asp-validation-for="Title" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Source" class="control-label"></label>
<input asp-for="Source" class="form-control" />
<span asp-validation-for="Source" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Description" class="control-label"></label>
<input asp-for="Description" class="form-control" />
<span asp-validation-for="Description" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="NewsTypeId" class="control-label"></label>
<select asp-for="NewsTypeId" class="form-control" asp-items="#ViewBag.NewsTypeId"></select>
<span asp-validation-for="NewsTypeId" class="text-danger"></span>
</div>
<div class="form-group">
<input type="submit" value="Create" class="btn btn-primary" />
</div>
</form>
</div>
For configuring one-to-many relationships,you could refer to
https://learn.microsoft.com/en-us/ef/core/modeling/relationships#definition-of-terms