Issue with DropDownlist in asp.net core mvc

DropDownList Data not inserted in database please someone help.

I m applying code first approach in asp.net core mvc

I am creating dropdown(country,state and city in table in mvc, but not inserted countryname,statename,cityname) in database see the image of inserted data in database.

Manager.cs

public class Manager {
[Key]
public int ManagerId {
get;
set;
}
public string ManagerName {
get;
set;
}
//Insertion in Manager table country state and city
public int countryId {
get;
set;
}
public string countryname {
get;
set;
}
public int stateId {
get;
set;
}
public string statename {
get;
set;
}
public int cityId {
get;
set;
}
public string cityname {
get;
set;
}
}
public class city {
public int cityId {
get;
set;
}
public string cityname {
get;
set;
}
[ForeignKey("state")]
public int stateId {
get;
set;
}
public virtual state states {
get;
set;
}
}
public class state {
public int stateId {
get;
set;
}
public string statename {
get;
set;
}
[ForeignKey("country")]
public int countryId {
get;
set;
}
public virtual country countrys {
get;
set;
}
}
public class country {
public int countryId {
get;
set;
}
public string countryname {
get;
set;
}
}

dbcontext.cs

public class dbcontext : IdentityDbContext
{
public dbcontext(DbContextOptions options) : base(options)
{
Database.EnsureCreated();
}
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
}
public virtual DbSet manages {get;set;}
public virtual DbSet countrys { get; set; }
public virtual DbSet states { get; set; }
public virtual DbSet citys { get; set; }
}

HomeController:

public class HomeController : Controller
{
private readonly dbcontext contxtclass;
public HomeController(dbcontext contxtclass)
{
this.contxtclass = contxtclass;
}
//not inserted countryname,stataname and cityname in database see the Referance image
public IActionResult Create()
{
//bound the country table record
List countrylist = new List();
countrylist = (from countrys in contxtclass.countrys select countrys).ToList();
countrylist.Insert(0,new country { countryname = "Select" });
ViewBag.listofcountry = countrylist;
//bound the state table record
List statelist = new List();
statelist = (from states in contxtclass.states select states).ToList();
statelist.Insert(0, new state { statename = "Select" });
ViewBag.listofstate = statelist;
//bound the city table record
List citylist = new List();
citylist = (from citys in contxtclass.citys select citys).ToList();
citylist.Insert(0, new city { cityname = "Select" });
ViewBag.listofcity = citylist;
return View();
}
[HttpPost]
public IActionResult Create(Manager manager)
{
contxtclass.Add(manager);
contxtclass.SaveChanges();
return View();
}

Create.cshtml

@model WebApplication2.Models.Manager
@{
Layout = null;
} @*here stop my debugger and give an error value can not be null*@
@* debugger can not check the below code *@
"viewport" content="width=device-width" />
Create
Manager
class="row">
class="col-md-4">
"Create">
//managername
"ModelOnly" class="text-danger">

class="form-group">

for

="ManagerName" class="control-label">

for

="ManagerName" class="form-control" />

for

="ManagerName" class="text-danger">

//country

class="row">

class="alert-danger" asp-validation-summary="ModelOnly">

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Ramesh Palanivel6y ago
Hi Rahul Patil,

Please check your countrylist property has value. I think there is no value is exist in that list. due to that null value exception occured.

Please share your country details in db if you have values in database. It might help us to proceed further.