try to send a viewmodel to view - asp.net

Question

I have a asp mvc project :
Model:
public class TeamDto
{
public int TenantId { get; set; }
public string Name { get; set; }
public List<UserListDto> Users { get; set; }
}
public class AddTeamViewModel
{
public TeamDto Team { get; set; }
public List<UserListDto> AllUsers { get; set; }
}
Controller:
public async Task<IActionResult> AddOrEditTeam(int id = 0)
{
var users = await _userAppService.GetAllUsers();
var view = new AddTeamViewModel { Team = new TeamDto(), AllUsers = users.ToList() };
if (id == 0) return View(view);
var team = await _teamAppService.GetTeamById(id);
return View(new AddTeamViewModel { AllUsers = users.ToList() , Team = team });
}
View:
<h4 class="m-portlet__head-caption">#(Model.Team.Id > 0 ? "Edit Team" : "Add Team")</h4>
I can not undrestand why I get this error:
An unhandled exception occurred while processing the request.
NullReferenceException: Object reference not set to an instance of an object.
AspNetCore.Areas_App_Views_Team_AddOrEditTeam.b__22_1()

Answer 1

It seems you are posting the value and then trying to send the viewmodel to a view. In this case, try redirecting to action instead of showing the View.
public async Task<IActionResult> AddOrEditTeam(int id = 0)
{
var users = await _userAppService.GetAllUsers();
var view = new AddTeamViewModel { Team = new TeamDto(), AllUsers = users.ToList() };
if (id == 0) return RedirectToAction("YourViewName",view);
var team = await _teamAppService.GetTeamById(id);
AddTeamViewModel teams = new AddTeamViewModel{
AllUsers = users.ToList(),
Team = team
};
return RedirectToAction("YourViewName", teams);
}
This will solve your object reference issue.