问题
here is my full code. who will see it then they could understand what i am trying to achieve. after seeing my code if anyone think there is problem in code design then please discuss with rectified version.
view model and model code
public class MainViewModel
{
public List<Student> Students { get; set; }
public int SelectedState = 0;
public int SelectedCity = 0;
}
public class Student
{
public int ID = 0;
public string Name = "";
public int StateID = 0;
public int CityID = 0;
public List<States> States { get; set; }
public List<Cities> Cities { get; set; }
}
public class States
{
public int ID = 0;
public string Name = "";
}
public class Cities
{
public int ID = 0;
public string Name = "";
}
Controller code from where i am populating my view model and model
public ActionResult Index()
{
MainViewModel oVm = new MainViewModel()
{
Students = new List<Student>() {
new Student
{
ID=1,
Name="JoyDev",
StateID=1,
CityID=1,
States=new List<States>()
{
new States
{
ID=1,
Name="WestBengal",
},
new States
{
ID=2,
Name="Bihar",
},
new States
{
ID=3,
Name="Orrisa",
}
},
Cities=new List<Cities>()
{
new Cities
{
ID=1,
Name="Alipur"
},
new Cities
{
ID=2,
Name="Asansol"
},
new Cities
{
ID=3,
Name="Andul"
}
}
},
//***********
new Student
{
ID=1,
Name="Mukti",
StateID=2,
CityID=1,
States=new List<States>()
{
new States
{
ID=1,
Name="WestBengal",
},
new States
{
ID=2,
Name="Bihar",
},
new States
{
ID=3,
Name="Orrisa",
}
},
Cities=new List<Cities>()
{
new Cities
{
ID=1,
Name="Janpur"
},
new Cities
{
ID=2,
Name="Madhubani"
},
new Cities
{
ID=3,
Name="Kanti"
}
}
},
//***********
new Student
{
ID=1,
Name="Somnath",
StateID=3,
CityID=2,
States=new List<States>()
{
new States
{
ID=1,
Name="WestBengal",
},
new States
{
ID=2,
Name="Bihar",
},
new States
{
ID=3,
Name="Orrisa",
}
},
Cities=new List<Cities>()
{
new Cities
{
ID=1,
Name="Chandapur"
},
new Cities
{
ID=2,
Name="Dhankauda"
},
new Cities
{
ID=3,
Name="Konarak"
}
}
}
}
};
return View();
}
view code where i was trying to bind drop down.
@model WebApplication1.Models.MainViewModel
@{
ViewBag.Title = "Home Page";
}
<div>
<table>
<tr>
<td>ID</td>
<td>Name</td>
<td>State</td>
<td>City</td>
</tr>
@foreach (var m in Model.Students)
{
<tr>
<td><input type="text" value="@m.ID" /></td>
<td><input type="text" value="@m.Name" /></td>
<td>
@Html.DropDownList("CityID", new SelectList(ViewData["CityList"] as List<SelectListItem>, "Value", "Text", m.CityID))
@Html.DropDownListFor(x => x.SelectedState new SelectList(Model.Students.States, "ID", "Name", Model.SelectedState), "-- Select States--", new { id = "cboState", @class = "edit-mode" })
</td>
<td>
@Html.DropDownListFor(x => x.SelectedCity new SelectList(Model.Students.Cities, "ID", "Name", Model.SelectedCity), "-- Select States--", new { id = "cboState", @class = "edit-mode" })
</td>
</tr>
}
</table>
</div>
main problem lies here
@Html.DropDownListFor(x => x.SelectedState new SelectList(Model.Students.States, "ID", "Name", Model.SelectedState), "-- Select States--", new { id = "cboState", @class = "edit-mode" })
main question is how to bind drop down with nested list type property Model.Students.States.
thanks
回答1:
My issue has been solved. so i like to give my updated code because the same code may help other.
my viewmodel and model classes
public class MainViewModel
{
public List<Student> Students { get; set; }
public int SelectedState = 0;
public int SelectedCity = 0;
}
public class Student
{
public int ID = 0;
public string Name = "";
public int StateID = 0;
public int CityID = 0;
public List<States> States { get; set; }
public List<Cities> Cities { get; set; }
}
public class States
{
public int ID { get; set; }
public string Name { get; set; }
}
public class Cities
{
public int ID { get; set; }
public string Name { get; set; }
}
Controller from where i populate my model
public class HomeController : Controller
{
public ActionResult Index()
{
MainViewModel oVm = new MainViewModel()
{
Students = new List<Student>() {
new Student
{
ID=1,
Name="JoyDev",
StateID=1,
CityID=1,
States=new List<States>()
{
new States
{
ID=1,
Name="WestBengal",
},
new States
{
ID=2,
Name="Bihar",
},
new States
{
ID=3,
Name="Orrisa",
}
},
Cities=new List<Cities>()
{
new Cities
{
ID=1,
Name="Alipur"
},
new Cities
{
ID=2,
Name="Asansol"
},
new Cities
{
ID=3,
Name="Andul"
}
}
},
//***********
new Student
{
ID=1,
Name="Mukti",
StateID=2,
CityID=1,
States=new List<States>()
{
new States
{
ID=1,
Name="WestBengal",
},
new States
{
ID=2,
Name="Bihar",
},
new States
{
ID=3,
Name="Orrisa",
}
},
Cities=new List<Cities>()
{
new Cities
{
ID=1,
Name="Janpur"
},
new Cities
{
ID=2,
Name="Madhubani"
},
new Cities
{
ID=3,
Name="Kanti"
}
}
},
//***********
new Student
{
ID=1,
Name="Somnath",
StateID=3,
CityID=2,
States=new List<States>()
{
new States
{
ID=1,
Name="WestBengal",
},
new States
{
ID=2,
Name="Bihar",
},
new States
{
ID=3,
Name="Orrisa",
}
},
Cities=new List<Cities>()
{
new Cities
{
ID=1,
Name="Chandapur"
},
new Cities
{
ID=2,
Name="Dhankauda"
},
new Cities
{
ID=3,
Name="Konarak"
}
}
}
}
};
return View(oVm);
}
}
view code
@model BuildTable.Models.MainViewModel
@{
ViewBag.Title = "Home Page";
}
<div>
<table>
<tr>
<td>ID</td>
<td>Name</td>
<td>State</td>
<td>City</td>
</tr>
@for(int i = 0; i < Model.Students.Count; i++)
{
<tr>
<td><input type="text" value="@Model.Students[i].ID" /></td>
<td><input type="text" value="@Model.Students[i].Name" /></td>
<td>
@Html.DropDownListFor(m => m.Students[i].StateID, new SelectList(Model.Students[i].States, "ID", "Name",Model.Students[i].StateID), "-- Select States--", new { @class = "edit-mode" })
</td>
<td>
@Html.DropDownListFor(m => m.Students[i].CityID, new SelectList(Model.Students[i].Cities, "ID", "Name",Model.Students[i].CityID), "-- Select Cities--", new { @class = "edit-mode" })
</td>
</tr>
}
</table>
</div>
thanks
回答2:
Models:
namespace MyProject.Models
{
public class ViewInfo
{
public int StateID { get; set; }
public int? CityID { get; set; }
}
public class Student
{
public int ID { get; set; }
public string FullName { get; set; }
public int CityID { get; set; }
}
public class State
{
public int ID { get; set; }
public string Name { get; set; }
}
public Class City
{
public int ID { get; set; }
public int StateID { get; set; }
public string Name { get; set; }
}
}
Controllers:
using MyProject.Models;
namespace MyProject.Controllers
{
public class StudentsController : Controller
{
private MyDBEntities _context;
public StudentsController()
{
this._context = new MyDBEntities();
}
// StudentsController
public ActionResult Index()
{
ViewBag.ViewInfo = new ViewInfo { StateID = 1 };
ViewBag.StateID = _context.States.Select(s => new SelectListItem { Value = s.ID, Text = s.Name }).ToList();
return View(_context.Students.ToList());
}
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Index(ViewInfo viewInfo)
{
ModelState.Clear();
ViewBag.ViewInfo = viewInfo;
ViewBag.StateID = _context.States.Select(s => new SelectListItem { Value = s.ID, Text = s.Name, Selected = s.ID == viewInfo.StateID }).ToList();
ViewBag.CityID = _context.Cities.Select(s => new SelectListItem { Value = s.ID, Text = s.Name, Selected = s.ID == viewInfo.CityID ?? 1 }).ToList();
var viewModel = _context.Students.Where(s => s.Cities.StateID == viewInfo.StateID && (viewInfo.CityID == null || s.CityID == viewInfo.CityID)).ToList();
return View(viewModel);
}
}
}
And the View:
@using MyProject.Models;
@model IEnumerable<MyProject.Models.Student>
@{
ViewBag.Title = "Students";
ViewInfo viewInfo = ViewBag.ViewInfo;
}
<div class="page-header">
<h2>Students</h2>
</div>
@using (Html.BeginForm())
{
@Html.AntiForgeryToken();
@Html.DropDownList("StateID", null, new { @class = "form-control" })
if(viewInfo.CityID != null){ @Html.DropDownList("CityID", null, new { @class = "form-control" }) }
<input type="submit" value="Filter" class="btn btn-primary" />
// Students Table
}
来源：https://stackoverflow.com/questions/34709891/asp-net-mvc-how-to-bind-dropdown-list-with-nested-list-type-property