I want to pass a collection of skills id from my view to controller action, i have a dropdownlist of SKILLS :
<select name="skills">
<option value="0">Java</option>
<option value="1">C++</option>
<option value="2">Fortran</option>
<option value="3">ASP</option>
</select>
i want that user can select many skills from dropdown and store their value in a collection ,i.e an array, and then post that array to action in controller as follow [employee and skills have a manytomany relationship]:
[HttpPost]
public ActionResult AddEmp(Employee emp ,IEnumerable<Skills> skills )
{
DBCtx db=new DbCtx();
db.employees.Add(emp);
var emp_id=db.SaveChanges();
var employee=db.employees.Find(emp_id);
foreach(item in skills)
{
var skill = db.skills.Find(item);
employee.skills.Add(skill);
}
db.SaveChanges();
return View();
}
How can i achieve this ,thanks in advance ....
You have quite few options on front end . Razor, Angular, Jquery... To simplfy things in following example i have used Razor view. I dont think you need to pass Skills as a strongly type object as you only need Id of selected Skills . Also in the example i have the skills list static / hard coded into razor view, ideally it should be bound from backend.
Saying that lets assume our Employee View Model as it follows
public class EmployeeViewModel
{
public EmployeeViewModel()
{
SelectedSkills=new List<int>();
}
public int Id { get; set; }
public string Name { get; set; }
public List<int> SelectedSkills { get; set; }
}
public class Skills
{
public int Id { get; set; }
public string Name { get; set; }
}
Then our Controller (EmployeeController.cs) would be .(please ignore the EF logic after data is bound to class)
public class EmployeeController : Controller
{
public ActionResult Index()
{
return View("Employee",new EmployeeViewModel());
}
[HttpPost]
public ActionResult AddEmp(EmployeeViewModel employee)
{
var idOfEmployee=AddEmployee(employee);
foreach (var item in employee.SelectedSkills)
{
AddSkill(idOfEmployee,item);
}
return View("Employee");
}
private void AddSkill(int idOfEmployee, int skillId)
{
// your EF logic
}
private int AddEmployee(EmployeeViewModel emp)
{
// your EF logic, get your id of the inserted employee
return 0;
}
}
Then our Employee.cshtml view could be
#using System.Web.UI.WebControls
#using WebApplication4.Controllers
#model WebApplication4.Controllers.EmployeeViewModel
#{
ViewBag.Title = "Employee";
}
<h2>Employee</h2>
#{var listItems = new List<Skills>
{
new Skills { Id = 0,Name="Java" },
new Skills { Id = 1,Name="C++" },
new Skills { Id = 2,Name="Fortran" }
};
}
#using (Html.BeginForm("AddEmp", "Employee"))
{
#Html.TextBoxFor(m => m.Name, new { autofocus = "New Employee" })
<br/>
#Html.ListBoxFor(m => m.SelectedSkills,
new MultiSelectList(listItems, "Id", "Name",#Model.SelectedSkills)
, new { Multiple = "multiple" })
<input type="submit" value="Submit" class="submit"/>
}
Related
Ok, I'm trying to do a proper dropdown in Core 3.1. In this example https://learn.microsoft.com/en-us/aspnet/core/mvc/views/working-with-forms?view=aspnetcore-3.1#the-select-tag-helper
Model has a new list with hardcoded values
public string Country { get; set; }
public List<SelectListItem> Countries { get; } = new List<SelectListItem>
{
new SelectListItem { Value = "MX", Text = "Mexico" },
new SelectListItem { Value = "CA", Text = "Canada" },
new SelectListItem { Value = "US", Text = "USA" },
};
I looked for examples where the list is coming from the database but they are very inconsistent. The only way I was able to do the dropdown list is with the ViewBag which is not advised.
I have two models. 1.
public partial class Glossary
{
public int UniqueId { get; set; }
public int Category { get; set; }
public string DisplayText { get; set; }
}
which is my view model
public partial class AdminUser
{
[Key]
public int Id { get; set; }
public string UserName { get; set; }
public string UserLocation { get; set; }
public string UserStatus { get; set; }
//public IEnumerable<Glossary> Glossary { get; set; } //I used this for ViewBag
public List<SelectListItem> UserLocations { get; } = new List<SelectListItem>
{
according to the example my query should go here
};
}
Here is my controller:
public IActionResult Create()
{
// This is the ViewBag that worked with HTML helpers, but I'm trying to use tag-helpers.
/*IEnumerable<SelectListItem> LocationsList = _context.Glossary.Where(x => x.Category == 1).Select(x => new SelectListItem
{
Value = x.UniqueId.ToString(),
Text = x.DisplayText
});
ViewBag.LocationsList = LocationsList;
*/
return View();
}
All examples that found were hardcoded lists and nothing with getting it from the database. What is the proper way to get the data from the Glossary table through the view model with ViewBag? Any pointers are appreciated.
ALSO:
When using this example: Select Tag Helper in ASP.NET Core MVC
When I used
public SelectList Employees { set; get; }
I got error: InvalidOperationException: The entity type 'SelectListGroup' requires a primary key to be defined. If you intended to use a keyless entity type call 'HasNoKey()'.
Both of my tables have PK and adding [Key] to Glossary model didn't fix it.
If you'd like to retrieve data from db and populate a dropdown with retrieved data through a view model (or ViewBag), you can refer to following code snippet.
In AdminUser view model class, include these properties
public string Selected_Glossary { get; set; }
public List<SelectListItem> Glossary_List { get; set; }
In controller
public IActionResult Create(AdminUser model)
{
var adminuser_model = new AdminUser
{
UserName="test"
//for other properties
};
//retrieve data from Glossary table
var items = _context.Glossary.Where(x => x.Category == 1).Select(x => new SelectListItem
{
Value = x.UniqueId.ToString(),
Text = x.DisplayText
}).ToList();
//pass dropdown items through a view model
adminuser_model.Glossary_List = items;
////pass dropdown items through ViewBag
//ViewBag.Glossary_List = items;
return View(adminuser_model);
}
In view page
#model AdminUser
#{
ViewData["Title"] = "Create";
}
<h1>Create</h1>
<form asp-controller="Home" asp-action="Create" method="post">
<select asp-for="Selected_Glossary" asp-items="Model.Glossary_List"></select>
#*populate it through ViewBag*#
#*<select asp-for="Selected_Glossary" asp-items="ViewBag.Glossary_List"></select>*#
<input type="submit" value="Submit" />
</form>
Test Result
What I have is a form with multiple inputs that I want to use to query database for some results. Form has some default values and it all works, however I have problem submitting it to itself.
The returned error is "No paramaterless constructor defined for this object" and it is caused by SelectList object.
I have tried this solution and made psUserType private with getter and setter and intialized it as empty list, but then my dropDown menu had no values on start. Not sure why GetUserTypes hadn't filled them.
What am I doing wrong here? How does one have both preselected values and also send the same model with user-selected values, while also displaying results on the same page?
Does it make sense to use the same model for all 3 actions: 1. display form and inputs with default values 2. post selected values during submit 3. return results and selected values? I've read this solution also but not sure how to use 2 or 3 separate models here.
Any help is appreciated. Thanks in advance.
Model
public class SearchDownloadsModel
{
public SelectList psUserType { get; private set; } //causes problem on submit
public string psText { get; set; }
public MultiSelectList psColumns { get; private set; }
public IEnumerable<ResultsRowModel> psResults { get; set; }
public SearchDownloadsModel()
{
this.psUserType = GetUserTypes();
this.psColumns = GetColumns();
this.psResults = new List<ResultsRowModel>(); //empty by default
}
public SelectList GetUserTypes()
{
List<SelectListItem> items = new List<SelectListItem>()
{
new SelectListItem { Value="user", Text="Single User" },
new SelectListItem { Value="group", Text="User group" },
...
};
return new SelectList(items, "Value", "Text");
}
public MultiSelectList GetColumns()
{
List<SelectListItem> items = new List<SelectListItem>()
{
new SelectListItem { Value = "user", Text="Username" },
new SelectListItem { Value = "file", Text="Filename" },
new SelectListItem { Value = "titl", Text="Title" },
new SelectListItem { Value = "auth", Text="Author" },
...
};
return new MultiSelectList(items, "Value", "Text");
}
}
public class ResultsRowModel
{
public int ID { get; set; }
public string EventTime { get; set; }
public string FileName { get; set; }
public string FilePath { get; set; }
public string UserName { get; set; }
...
}
View
#model Proj.Models.SearchDownloadsModel
#using (Html.BeginForm("Downloads", "Home", FormMethod.Post))
{
#Html.DropDownListFor(x => x.psUserType, Model.psUserType)
#Html.TextBoxFor(x => x.psText)
#Html.ListBoxFor(x => x.psColumnsSelected, Model.psColumns, new { multiple = "multiple" })
<button type="submit" class="btn btn-primary">Search</button>
}
#if (Model.psResults != null && Model.psResults.Any())
{
<table>
<tr>
<th>User</th>
<th>File</th>
</tr>
#foreach (var row in Model.psResults)
{
<tr>
<td>#row.UserName</td>
<td>#row.FileName</td>
</tr>
}
</table>
}
Controller
[HttpGet]
public ActionResult Downloads()
{
SearchDownloadsModel model = new SearchDownloadsModel();
model.psColumnsSelected = new List<string>() { "user", "file" }; //preselected values
return View(model);
}
[HttpPost]
public ActionResult Downloads(SearchDownloadsModel model)
{
model.psResults = queryDatabase(model);
return View(model);
}
private List<ResultsRowModel> queryDatabase(SearchDownloadsModel model)
{
//...
}
EDIT: Added ResultsRowModel under SearchDownloadsModel
In ASP.NET MVC you should only put variables containing the posted or selected values in the ViewModel class. Select List items are considered extra info and are typically passed from the Action Method into the View (.cshtml) using ViewBag items.
Many of the rendering extension methods are even written specifically for such an approach, leading to code such as this:
Controller
ViewBag.PersonID = persons.ToSelectList(); // generate SelectList here
View
#Html.DropDownListFor(model => model.PersonID)
#* The above will look for ViewBag.PersonID, based on the name of the model item *#
The DropDownListFor generates a <select> element with the name of the property you bind it to. When you submit the form, that name will be included as one of the form fields and its value will be the option's value you select.
You're binding the DropDownList to a property of type SelectList (psUserType) and when your action is called, a new instance of SelectList must be created in order to bind the form field to it. First of all, the SelectList class does not have a parameterless constructor and, thus, your error. Secondly, even if a SelectList could be created as part of model binding, the <select> element is submitting a string value which wouldn't be convertible to SelectList anyways.
What you need to do is to add a string property to your SearchDownloadsModel, for example:
public string SelectedUserType { get; set; }
Then bind the dropdownlist to this property:
#Html.DropDownListFor(x => x.SelectedUserType, Model.psUserType)
When you submit the form, this new property will have the value you selected in the drop down.
Peter's answer and Stephen's comments helped me solve the problem.
Pehaps someone will find it useful.
Any further suggestions always welcome.
Model
public class PobraniaSzukajModel
{
public IEnumerable<SelectListItem> UserTypes { get; set; }
public string psSelectedUserType { get; set; }
public IEnumerable<SelectListItem> Columns { get; set; }
public IEnumerable<string> psSelectedColumns { get; set; }
public string psText { get; set; }
public ResultsModel psResults { get; set; }
}
View
#Html.ListBoxFor(x => x.psSelectedUserType, Model.Columns)
#Html.TextBoxFor(x => x.psText)
#Html.ListBoxFor(x => x.psSelectedColumns, Model.Columns)
Controller
[HttpGet]
public ActionResult Downloads()
{
SearchDownloadsModelmodel = new SearchDownloadsModel();
model.UserTypes = GetUserTypes();
model.Columns = GetColumns();
model.psColumnsSelected = new List<string>() { "user", "file" }; //preselected values
return View(model);
}
[HttpPost]
public ActionResult Downloads(SearchDownloadsModel model)
{
model.UserTypes = GetUserTypes();
model.Columns = GetColumns();
model.psResults = GetResults(model);
return View(model);
}
public SelectList GetUserTypes()
{
//...
}
public MultiSelectList GetColumns()
{
//...
}
public ResultsModel GetResults()
{
//...
}
First post here, so i'm sorry if this post is not very good!
I am currently building a web application using asp.net, and ran in to this problem:
The model item passed into the dictionary is of type 'Daily_Planner.Models.DayPlanPartialview', but this dictionary requires a model item of type 'Daily_Planner.Models.Group'
It seems like I am having a problem with passing on the right model. I am using several partial views and I am afraid that I may be using my models wrong, however I can not find out what it is. I have tried giving some adequate information, however if you need more I will be more than willing to post more of the code.
Partial view _GroupManage:
#model IEnumerable<Daily_Planner.Models.Group>
<select>
#foreach (var item in Model)
{
<option value="#item.Id">#item.GroupName</option>
}
</select>
Partial view _layout:
#if (Request.IsAuthenticated)
{
#Html.ActionLink("Daily Planner", "Index", "Home", new { area = "" }, new { #class = "navbar-brand" })
}
else
{
#Html.ActionLink("Daily Planner", "Login", "Account", new { area = "" }, new { #class = "navbar-brand" })
}
#if (Request.IsAuthenticated)
{
{ Html.RenderPartial("_GroupManage"); }
#Html.Partial("_LoginPartial")
}
Model:
namespace Daily_Planner.Models
{
public class DayPlanPartialview
{
public DayPlan displayComments { get; set; }
public Group groupM { get; set; }
public IEnumerable<Daily_Planner.Models.DayPlan> ListofComments { get; set;}
public IEnumerable<Daily_Planner.Models.Group> groupmanage{ get; set; }
}
HomeController
namespace Daily_Planner.Controllers
{
public class HomeController : Controller
{
private ApplicationDbContext db = new ApplicationDbContext();
private DayPlanPartialview pv = new DayPlanPartialview();
[Authorize]
public ActionResult Index()
{
// Add list of comments with newest comment first // .Take(10).ToList(); will only show the last 10 posts
pv.ListofComments = db.DayPlans.OrderByDescending(x => x.DateCreated).ToList();
return View(pv);
}
[HttpPost]
[Authorize]
public ActionResult Index(DayPlanPartialview dayP)
{
dayP.displayComments.ApplicationUserId = User.Identity.GetUserId();
dayP.displayComments.DateCreated = DateTime.Now;
db.DayPlans.Add(dayP.displayComments);
db.SaveChanges();
pv.ListofComments = db.DayPlans.ToList();
return RedirectToAction("");
}
#model IEnumerable<Daily_Planner.Models.Group>
<select>
#foreach (var item in Model)
{
<option value="#item.Id">#item.GroupName</option>
}
</select>
I have a list of checkboxes generated in the View using the following code:
using (Html.BeginForm("UpdateItems", "Home", FormMethod.Post)) {
foreach (myProject.Models.item t in ViewBag.Items)
{
<div>
#Html.CheckBox("chkT", t.selected, new { id = "chkT" + t.id })
#Html.Label(t.description)
</div>
}
<button type="submit" class="mfButton" value="SaveItemss">Save Changes</button>
}
What I need to is to be able to get the values of these generated checkboxes in the controller. So far I have the following:
public ActionResult UpdateItemss(List<bool> chkT)
{
return View();
}
However this being a boolean only give me true or false and the id of the values to which they belong. Is there a way get the name/value pair?
Thanks
Rather than using ViewBag, I would use strongly typed view. I would create a model and add the lists as property. My Models should look like:
public class Test
{
public int Id { get; set; }
public List<Item> Items { get; set; }
}
public class Item
{
public int Id { get; set; }
public bool Selected { get; set; }
public string Description { get; set; }
}
In the controller I am passing the model with dummy data:
public ActionResult Index()
{
Test model = new Test()
{
Id = 1,
Items = new List<Item>()
{
new Item {Id = 1, Selected = false, Description = "Item1"},
new Item {Id = 2, Selected = false, Description = "Item2"},
new Item {Id = 3, Selected = false, Description = "Item3"}
}
};
return View(model);
}
In my View I am using for loop to generate list of Items:
#model MVCTest.Models.Test
#using (Html.BeginForm("UpdateItems", "Home", FormMethod.Post)) {
#Html.HiddenFor(m=>m.Id)
for (int i = 0; i < Model.Items.Count; i++)
{
<div>
#Html.HiddenFor(m=>m.Items[i].Id)
#Html.CheckBoxFor(m=>m.Items[i].Selected, new {id = "checkbox_" + i} )
#Html.DisplayFor(m=>m.Items[i].Description)
</div>
}
<button type="submit" class="mfButton" value="SaveItemss">Save Changes</button>
}
In the controller I am catching the posted model and find all Items inside its Items property:
[HttpPost]
public ActionResult UpdateItems(Test model)
{
if (model != null)
{
// You can access model.Items here
//Do whatever you need
}
return View(model);
}
I would suggest to read this blog: ASP.NET Wire Format for Model Binding to Arrays, Lists, Collections, Dictionaries.
Is it possible to have a single view model with a list that is used for a dropdownlist and also get the selected value of the dropdownlist from the view model when I post a form?
If so, how can I do this?
Sure, as always start by defining your view model:
public class MyViewModel
{
public int? SelectedItemValue { get; set; }
public IEnumerable<Item> Items { get; set; }
}
public class Item
{
public int? Value { get; set; }
public string Text { get; set; }
}
then the controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new MyViewModel
{
// TODO: Fill the view model with data from
// a repository
Items = Enumerable
.Range(1, 5)
.Select(i => new Item
{
Value = i,
Text = "item " + i
})
};
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
// TODO: based on the value of model.SelectedItemValue
// you could perform some action here
return RedirectToAction("Index");
}
}
and finally the strongly typed view:
<% using (Html.BeginForm()) { %>
<%= Html.DropDownListFor(
x => x.SelectedItemValue,
new SelectList(Model.Items, "Value", "Text")
) %>
<input type="submit" value="OK" />
<% } %>