问题
I have this problem where i want to make 7 dropdowns for each day of the week. In each one of those dropdowns i wish to add the same data.
My ViewModel:
public class WeekDienstCreateViewModel
{
public WeekDienst weekDienst {get; set;}
public List<DienstPerWeekDienst> diensten { get; set; }
public WeekDienstCreateViewModel() { }
}
My Create Method in Controller: As u can see I add everything allready except DienstId which is want to add with my dropdowns.
public ActionResult Create(int id)
{
WeekDienst wd = _service.FindWeekDienst(id);
WeekDienstCreateViewModel vm = new WeekDienstCreateViewModel();
vm.diensten = new List<DienstPerWeekDienst>();
vm.weekDienst = wd;
for (int i = 1; i <= 7; i++)
{
DienstPerWeekDienst dpwd = new DienstPerWeekDienst();
dpwd.volgnummer = i;
dpwd.WeekDienstId = wd.Id;
vm.diensten.Add(dpwd);
}
ViewBag.Diensten = _service.DienstenList(wd.AfdelingId);
return View(vm);
}
Classes:
public class DienstPerWeekDienst
{
[Key]
public int Id { get; set; }
[Required]
public int WeekDienstId { get; set; }
[Required]
public int DienstId { get; set; }
[Required]
[Range(1, 7)]
public int volgnummer { get; set; }
[ForeignKey("WeekDienstId")]
public virtual WeekDienst WeekDienst { get; set; }
[ForeignKey("DienstId")]
public virtual Dienst Dienst { get; set; }
public virtual ICollection<WeekDienst> WeekDiensten { get; set; }
}
public class WeekDienst
{
[Key]
public int Id { get; set; }
[Required]
public int AfdelingId { get; set; }
[Required]
[StringLength(5, ErrorMessage = "Value for {0} cannot exceed {1} characters.")]
[RegularExpression(@"^[a-zA-Z0-9]{5}$", ErrorMessage = "Verplicht 5 cijfers lang.")]
public string code { get; set; }
[DisplayName("Template")]
public bool template { get; set; }
[ForeignKey("AfdelingId")]
public virtual Afdeling Afdeling { get; set; }
}
And in my view i wish to create 7 dropdowns where i put in all my "Diensten" (class Dienst, fk in DienstPerWeekDienst). When I choose 1 i wish to add the "DienstId" into the "DienstPerWeekDienst" class.
So in my View i got this:
@foreach (var day in Model.diensten)
{
var currentDay=day;
@Html.DropDownListFor(currentDropDown=>currentDay, new SelectList(ViewBag.Diensten, "Value", "Text"))
}
I Wish to postback the chosen "Diensten" and create the "WeekDienst" but now i am just posting a null "DienstPerDienstWeekCreateViewModel". How am I able to fix this?
Thanks in Advance
FIX (Thanks to Siva Gopal)
I fixed this by doing:
@for (int i = 0; i < @Model.diensten.Count; i++)
{
@Html.HiddenFor(m => (m.diensten[i].volgnummer))
@Html.HiddenFor(m => (m.diensten[i].WeekDienstId))
@Html.DropDownListFor(m=> (m.diensten[i].DienstId), new SelectList(ViewBag.Diensten, "Value", "Text"))
}
回答1:
You may try using
@foreach (var day in Model.diensten)
{
var currentDay=day;
@Html.DropDownListFor(currentDropDown=>currentDay, new SelectList(ViewBag.Diensten, "PropertyName_Holding_Value", "PropertyName_Holding_DisplayText"), new { })
} //This uses the Lambda Expression. Your dropdown Name/Id would be 1,2,3 etc. based on currentDay value.
OR
@foreach (var day in Model.diensten)
{
var currentDay=day;
var dropdownName=string.Format("diensten[{0}]",day-1); //If you want to model bind the selected dropdown value to input entity in POST request. The final dropdownName format should match the hierarchy of the property inside input entity/object. Even without this name formation, you can still POST the selected value back using Jquery/Javascript.
@Html.DropDownList(dropdownName, new SelectList(ViewBag.Diensten, "PropertyName_Holding_Value", "PropertyName_Holding_DisplayText"), new {})
} //
Note for Value Post back/model bind on full Page submit: To be able to model bind/POST back values to the server, the html element names corresponding to the properties should be rendered as follows: Suppose if you display Employee.Department.Name, then name of textbox, displaying the Department Name in View should match Department_ReferenceName_Inside_Employee.Name for model binding.
Model: public class Employee { public int Id { get; set; } public string Name { get; set; } public string City { get; set; } public Department EmpDepartment { get; set; } public List SubOrdinates { get; set; } } public class Department { public string Name { get; set; } }
Controller:
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.Message = "Welcome to ASP.NET MVC!";
//Prepare the model and send it to the view
Employee emp = new Employee { EmpDepartment = new Department { Name = "IT" } };
emp.SubOrdinates = new List<Employee> { new Employee { Name = "Emp1" }, new Employee { Name = "Emp2" } };
return View(emp);
}
[HttpPost]
public ActionResult Index(Employee emp)
{ //Put a break-point here and see how the modified values in view are flowing into emp..
return View(emp);
}
public ActionResult About()
{
return View();
}
}
View:
@model MvcApplication.Models.Employee
@using (Html.BeginForm())
{
@Html.TextBoxFor(m => m.EmpDepartment.Name)
@Html.LabelForModel("SubOrdinates :")
for (int i = 0; i < @Model.SubOrdinates.Count; i++)
{
@Html.TextBoxFor(m => (m.SubOrdinates[i].Name))
}
<input type="submit" name="name" value="Submit" /> }
ViewSource/PageSource: The above text box syntax will be rendered as :
<input id="EmpDepartment_Name" name="EmpDepartment.Name" type="text" value="IT" /> <!--See above html : name=EmpDepartment.Name -->
<label for="">SubOrdinates :</label>
<input id="SubOrdinates_0__Name" name="SubOrdinates[0].Name" type="text" value="Emp1" />
<input id="SubOrdinates_1__Name" name="SubOrdinates[1].Name" type="text" value="Emp2" /> <!--See above html for how collection item Name(s) are being renderd by view engine-->
<input type="submit" name="name" value="Submit" />
回答2:
@foreach (var day in Model.diensten)
{
var currentDay = day;
@Html.DropDownListFor(x => currentDay, new SelectList(ViewBag.Diensten, "Value", "Text"), new { @id = "DienstList" })
}
回答3:
List<MvcApplication1.Models.Country> cntry = db.Countries.ToList();
SelectListItem sss = new SelectListItem();
List<SelectListItem> sltst = new List<SelectListItem>();
sss.Text = "Select";
sss.Value = "0";
sltst.Add(sss);
foreach (MvcApplication1.Models.Country s in cntry){
SelectListItem s1 = new SelectListItem();
s1.Text = s.Country1;
s1.Value = Convert.ToString(s.Id);
sltst.Add(s1);}
@Html.DropDownList("country", sltst, new { @id = "country" })
来源：https://stackoverflow.com/questions/9513385/creating-a-dropdown-in-mvc3-c-sharp-with-viewmodel-and-easy-model-binding-on-pos