WCF---Consuming CRUD operation using Linq in ASP.NET MVC application? - asp.net-mvc

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First step...Opened WCF created IService:
namespace CRUDOperationWCFMVC
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
[ServiceContract]
public interface IService1
{
[OperationContract]
bool CreateDetails(EmployeeDetails employeeDetails);
[OperationContract]
bool UpdateDetails(EmployeeDetails employeeDetails);
[OperationContract]
bool DeleteDetails(int id);
[OperationContract]
List<EmployeeDetails> GetDetails();
}
public class EmployeeDetails
{
[DataMember]
public int EmpID { get; set; }
[DataMember]
public string Name { get; set; }
[DataMember]
public string Location { get; set; }
[DataMember]
public int? Salary { get; set; }
}
}
Step 2: then I implemented service code:
public class Service1 : IService1
{
DataClasses1DataContext dcd = new DataClasses1DataContext();
public bool CreateDetails(EmployeeDetails employeeDetails)
{
Nevint emp = new Nevint();
emp.EmpID= employeeDetails.EmpID;
emp.Name = employeeDetails.Name;
emp.Location = employeeDetails.Location;
emp.Salary = employeeDetails.Salary;
dcd.Nevints.InsertOnSubmit(emp);
dcd.SubmitChanges();
return true;
}
public bool DeleteDetails(int id)
{
var delete = (from v in dcd.Nevints where v.EmpID==id select v).FirstOrDefault();
dcd.Nevints.DeleteOnSubmit(delete);
dcd.SubmitChanges();
return true;
}
public List<EmployeeDetails> GetDetails()
{
List<EmployeeDetails> details = new List<EmployeeDetails>();
var select= (from v in dcd.Nevints select v);
foreach (var i in select)
{
EmployeeDetails emp = new EmployeeDetails();
emp.EmpID = i.EmpID;
emp.Name = i.Name;
emp.Location = i.Location;
emp.Salary = i.Salary;
details.Add(emp);
}
return details;
}
public bool UpdateDetails(EmployeeDetails employeeDetails)
{
var update = (from v in dcd.Nevints.ToList() where employeeDetails.EmpID==v.EmpID select v).FirstOrDefault();
update.EmpID = employeeDetails.EmpID;
update.Name = employeeDetails.Name;
update.Location = employeeDetails.Location;
update.Salary = employeeDetails.Salary;
dcd.SubmitChanges();
return true;
}
}
Step 3: then I add linq to sql, opened my ASP.NET MVC project for consuming, and added a controller and wrote this code:
namespace ConsumingClient.Controllers
{
public class EmpdetailsController : Controller
{
ServiceReference1.Service1Client serobj=new ServiceReference1.Service1Client();
ServiceReference1.EmployeeDetails empdetails=new ServiceReference1.EmployeeDetails();
// GET: Empdetails
public ActionResult Index()
{
List<employee> lstemp = new List<employee>();
var result = serobj.GetDetails();
foreach (var i in result)
{
employee emp = new employee();
empdetails.EmpID = i.EmpID;
empdetails.Name = i.Name;
empdetails.Location = i.Location;
empdetails.Salary = i.Salary;
lstemp.Add(emp);
}
return View(result);
}
// GET: Empdetails/Details/5
public ActionResult Details(int id)
{
Employees emp = new Employees();
return View();
}
// GET: Empdetails/Create
public ActionResult Create()
{
return View();
}
// POST: Empdetails/Create
[HttpPost]
public ActionResult Create(Employees employees)
{
try
{
// TODO: Add insert logic here
empdetails.EmpID=employees.EmpID;
empdetails.Name = employees.Name;
empdetails.Location = employees.Location;
empdetails.Salary = employees.Salary;
serobj.CreateDetails(empdetails);
return RedirectToAction("Index");
}
catch
{
return View();
}
}
// GET: Empdetails/Edit/5
public ActionResult Edit(int id)
{
Employees emp = new Employees();
var result = serobj.GetDetails().FirstOrDefault(a=>a.EmpID==id);
emp.EmpID = result.EmpID;
emp.Name = result.Name;
emp.Location = result.Location;
emp.Salary = result.Salary;
return View(emp);
}
// POST: Empdetails/Edit/5
[HttpPost]
public ActionResult Edit(Employees employees)
{
try
{
// TODO: Add update logic here
empdetails.EmpID = employees.EmpID;
empdetails.Name = employees.Name;
empdetails.Location = employees.Location;
empdetails.Salary = employees.Salary;
serobj.UpdateDetails(empdetails);
return RedirectToAction("Index");
}
catch
{
return View(employees);
}
}
// GET: Empdetails/Delete/5
public ActionResult Delete(int id)
{
Employees emp = new Employees();
var result = serobj.GetDetails().FirstOrDefault(a=>a.EmpID==id);
emp.EmpID = result.EmpID;
emp.Name = result.Name;
emp.Location = result.Location;
emp.Salary = result.Salary;
return View(emp);
}
// POST: Empdetails/Delete/5
[HttpPost]
public ActionResult Delete(int id, FormCollection collection)
{
try
{
// TODO: Add delete logic here
serobj.DeleteDetails(id);
return RedirectToAction("Index");
}
catch
{
return View(id);
}
}
}
}
Data was displaying fine. I can create data.
However, when I click on edit and delete, I'm getting an error:
ERROR Message "Server Error in '/' Application.
The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult Edit(Int32)' in 'ConsumingClient.Controllers.EmpdetailsController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters

This error is thrown if you attempt to call this controller action and you do not specify the id either in the path portion or as query string parameter. Since your controller action takes an id as parameter you should make sure that you always specify this parameter.
Make sure that when you are requesting this action you have specified a valid id in the url:
http://example.com/somecontroller/Edit/123
If you are generating an anchor, make sure there's an id:
#Html.ActionLink("Edit", "somecontroller", new { id = "123" })
If you are sending an AJAX request, also make sure that the id is present in the url.
If on the other hand the parameter is optional, you could make it a nullable integer:
public ActionResult Edit(int? id)
but in this case you will have to handle the case where the parameter value is not specified.
https://coderedirect.com/questions/197477/mvc-the-parameters-dictionary-contains-a-null-entry-for-parameter-k-of-non-n

Related

public ActionResult Index5() { return RedirectToAction("Index","Student", new { name = "ATHUL",address="TVM" }); }

public ActionResult Index(string name, string address)
{
Student obj = new Student()
{
name = "VAZEEM",
address="CALCUT"
};
return View(obj);
}
public ActionResult Index5()
{
return RedirectToAction("Index","Student", new { name = "ATHUL",address="TVM" });
}
please corrept the code
change index detail to index5 detail

Can't convert from int to "classname"

While building a ASP.NET-MVC website I was trying to implement a EDIT page on my website, but I'm having some difficulties, particulary in my Controller. The error is in this class, pointing to the ID:
public IActionResult Edit(int ID = 0)
{
GestaoAlertas _teste = addresses.Contains(ID);
return View(_teste);
}
And the error says:
It is not possible to convert from int to "hdsportal.GestaoAlertas"
Controller:
public class HomeController : Controller
{
SqlCommand com = new SqlCommand();
SqlDataReader dr;
SqlConnection con = new SqlConnection();
List<GestaoAlertas> addresses = new List<GestaoAlertas>();
private readonly ILogger<HomeController> _logger;
public HomeController(ILogger<HomeController> logger)
{
_logger = logger;
con.ConnectionString = "secret";
}
public IActionResult Gestao_Alertas()
{
FetchData();
return View(addresses);
}
[Route("")]
public IActionResult Index()
{
FetchData();
return View(addresses);
}
public IActionResult Edit(int ID = 0)
{
GestaoAlertas _teste = addresses.Contains(ID);
return View(_teste);
}
public IActionResult Privacidade()
{
return View();
}
public IActionResult Gestao_Utilizadores()
{
return View();
}
public IActionResult Contatos()
{
return View();
}
public IActionResult QuemSomos()
{
return View();
}
private void FetchData()
{
if (addresses.Count > 0)
{
addresses.Clear();
}
try
{
con.Open();
com.Connection = con;
com.CommandText = "SELECT [ID], [SYSTEM_NAME], [SYSTEM_STATUS], [SYSTEM_SHORTMSG] FROM [CORE_SYS_STATUS]";
dr = com.ExecuteReader();
while (dr.Read())
{
addresses.Add(new GestaoAlertas()
{
ID = (int)dr["ID"]
,
SYSTEM_NAME = dr["SYSTEM_NAME"].ToString()
,
SYSTEM_STATUS = dr["SYSTEM_STATUS"].ToString()
,
SYSTEM_SHORTMSG = dr["SYSTEM_SHORTMSG"].ToString()
});
}
con.Close();
}
catch (Exception ex)
{
throw ex;
}
}
[ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
public IActionResult Error()
{
return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
}
}
Model:
public class GestaoAlertas
{
public int ID { get; set; }
public string SYSTEM_NAME { get; set; }
public string SYSTEM_STATUS { get; set; }
public string SYSTEM_SHORTMSG { get; set; }
}
Issue & Concern
According to List<T>.Contains(T), you need parse T object which is GestaoAlertas object to your addresses (List<GestaoAlertas> type).
Hence, you get the error below as it is an unmatched type with int
It is not possible to convert from int to "hdsportal.GestaoAlertas"
for this line:
GestaoAlertas _teste = addresses.Contains(ID);
And List<T>.Contains(T) returns the boolean result.
public bool Contains (T item);
Determines whether an element is in the List.
Solution(s)
Assumptions:
addresses contain GestaoAlertas records
You can get GestaoAlertas element from addresses by ID with either of these LINQ methods:
Pre-requisite:
Import System.Linq namespace.
using System.Linq;
Solution 1: Enumerable.SingleOrDefault
Returns a single, specific element of a sequence, or a default value if that element is not found.
Note: It will throw InvalidOperationException if input sequence contains more than one element. Good to be use for unique identifier such as ID.
GestaoAlertas _teste = addresses.SingleOrDefault(x => x.ID == ID);
Solution 2: Enumerable.Single
Returns a single, specific element of a sequence.
Note: It will throw ArgumentNullException if it returns null.
GestaoAlertas _teste = addresses.Single(x => x.ID == ID);
Solution 3: Enumerable.FirstOrDefault
Returns the first element of a sequence, or a default value if no element is found.
GestaoAlertas _teste = addresses.FirstOrDefault(x => x.ID == ID);
Solution 4: Enumerable.First
Returns the first element of a sequence.
Note: It will throw ArgumentNullException if it returns null.
GestaoAlertas _teste = addresses.First(x => x.ID == ID);

Get recent inserted Id and send in to another controllers view

EDITED:
I have Created CRUD Functions for each Modals and now i am trying to get recent Inserted Id and use it in different view.
Here is what I have tried so far
I have created 2 classes(Layer based) for CRUD function for each ContextEntities db to practice pure OOP recursive approach and following is the code.
1. Access Layer
ViolatorDB
public class ViolatorDB
{
private TPCAEntities db;
public ViolatorDB()
{
db = new TPCAEntities();
}
public IEnumerable<tbl_Violator> GetALL()
{
return db.tbl_Violator.ToList();
}
public tbl_Violator GetByID(int id)
{
return db.tbl_Violator.Find(id);
}
public void Insert(tbl_Violator Violator)
{
db.tbl_Violator.Add(Violator);
Save();
}
public void Delete(int id)
{
tbl_Violator Violator = db.tbl_Violator.Find(id);
db.tbl_Violator.Remove(Violator);
Save();
}
public void Update(tbl_Violator Violator)
{
db.Entry(Violator).State = EntityState.Modified;
Save();
}
public void Save()
{
db.SaveChanges();
}
}
2. Logic Layer
ViolatorBs
public class ViolatorBs
{
private ViolatorDB objDb;
public ViolatorBs()
{
objDb = new ViolatorDB();
}
public IEnumerable<tbl_Violator> GetALL()
{
return objDb.GetALL();
}
public tbl_Violator GetByID(int id)
{
return objDb.GetByID(id);
}
public void Insert(tbl_Violator Violator)
{
objDb.Insert(Violator);
}
public void Delete(int id)
{
objDb.Delete(id);
}
public void Update(tbl_Violator Vioaltor)
{
objDb.Update(Vioaltor);
}
}
And Finally using Logic Layer functions in presentation Layer.Here insertion is performed as:
public class CreateViolatorController : Controller
{
public TPCAEntities db = new TPCAEntities();
private ViolatorBs objBs;
public CreateViolatorController()
{
objBs = new ViolatorBs();
}
public ActionResult Index()
{
var voilator = new tbl_Violator();
voilator=db.tbl_Violator.Add(voilator);
ViewBag.id = voilator.VID;
return View();
}
[HttpPost]
public ActionResult Create(tbl_Violator Violator)
{
try
{
if (ModelState.IsValid)
{
objBs.Insert(Violator);
TempData["Msg"] = "Violator Created successfully";
return RedirectToAction("Index");
}
else
{
return View("Index");
}
}
catch (Exception ex)
{
TempData["Msg"] = "Failed..." + ex.Message + " " + ex.ToString();
return RedirectToAction("Index");
}
}
}
Now here is the main part how do i get perticuller inserted id in another controller named Dues while performing insertion ?
In sqlqery I would have used ##IDENTITY but in Entity Framework I'm not sure.
I'm new to mvc framework any suggestion or help is appreciated Thanks in Advance.
Once you save your db context the id is populated back to your entity by EF automatically.
for example.
using(var context = new DbContext())
{
var employee = new Employee(); //this has an id property
context.Employees.Add(employee);
context.SaveChanges();
var id = employee.id; // you will find the id here populated by EF
}
You dont need to add and save your table as you have done this already in your voilatorDB class just fetch the last id like following
var id = yourTableName.Id;
db.yourTableName.find(id);
Or you can simply write one line code to achive that using VoilatorBs class function
GetbyID(id);

Entity framework savechanges error

I have a wizard step in which a user fills in fields. I then use json to save the values into my database for each wizard step.
However, in my repository I have my savechanges(). But it wont save the changes, instead it throws an error:
Entities in 'NKImodeledmxContainer.SelectedQuestion' participate in the 'QuestionSelectedQuestion' relationship. 0 related 'Question' were found. 1 'Question' is expected.
Anyone know how to get rid of the error? Do I have to get the ID from Question and save it aswell to my database or can I change something in EF so the error message is not getting thrown?
This is my post in my controller:
[HttpPost]
public JsonResult AnswerForm(int id, SelectedQuestionViewModel model)
{
bool result = false;
var goalCardQuestionAnswer = new GoalCardQuestionAnswer();
goalCardQuestionAnswer.SelectedQuestion = new SelectedQuestion();
goalCardQuestionAnswer.SelectedQuestion.Id = model.QuestionID;
goalCardQuestionAnswer.Comment = model.Comment;
goalCardQuestionAnswer.Grade = model.Grade;
if (goalCardQuestionAnswer.Grade != null)
{
answerNKIRepository.SaveQuestionAnswer(goalCardQuestionAnswer);
answerNKIRepository.Save();
result = true;
return Json(result);
}
answerNKIRepository.SaveQuestionAnswer(goalCardQuestionAnswer);
answerNKIRepository.Save();
return Json(result);
}
My Repository
public class AnswerNKIRepository
{
private readonly NKImodeledmxContainer db = new NKImodeledmxContainer();
public List<SelectedQuestion> GetAllSelectedQuestionsByGoalCardId(int goalCardId)
{
return db.SelectedQuestion.Where(question => question.GoalCard.Id == goalCardId).ToList();
}
public void SaveQuestionAnswer(GoalCardQuestionAnswer goalCardQuestionAnswer)
{
db.GoalCardQuestionAnswer.AddObject(goalCardQuestionAnswer);
}
public void Save()
{
db.SaveChanges();
}
}
This is my ViewModel:
public class SelectedQuestionViewModel
{
public int? Grade { get; set; }
public string Comment { get; set; }
public string SelectedQuestionText { get; set; }
public int QuestionID { get; set; }
}
This is my database model:
The exception complains that SelectedQuestion.Question is a required navigation property but you don't set this property in your code. Try to load the question by Id from the repository and set it to the SelectedQuestion.Question reference: Replace this line ...
goalCardQuestionAnswer.SelectedQuestion.Id = model.QuestionID;
...by...
goalCardQuestionAnswer.SelectedQuestion.Question =
answerNKIRepository.GetQuestionById(model.QuestionID);
And in your repository add the method:
public Question GetQuestionById(int id)
{
return db.Question.Single(q => q.Id == id);
}

Using ViewModels in asp.net mvc 3

Here is my scenario: (These all have to accomplished in the same view as an accepted requirement)
User enters a few search criterias to search users.
Page lists the search results with an update link besides.
User clicks on one of the update links and a form appears to enable editing the data.
User does changes and saves the data that binded to form.
I used a view model for this view. Here it is.
[Serializable]
public class UserAddModel
{
public UserSearchCriteria UserSearchCriteria { get; set; }
public UserEntity User { get; set; }
public List<UserPrincipalDto> SearchResults { get; set; }
}
And here is my controller:
using System;
namespace x.Web.BackOffice.Controllers
{
[Export]
[PartCreationPolicy(CreationPolicy.NonShared)]
[Authorize(Roles = "Admin")]
public class UserController : Controller
{
private readonly IAuthentication _authentication;
private readonly List<RoleEntity> roles = new Y.Framework.Data.Repository<RoleEntity>().Get(null).ToList();
private Repository<UserEntity> repository = new Repository<UserEntity>();
[ImportingConstructor]
public UserController(IAuthentication authentication)
{
this._authentication = authentication;
}
public ActionResult Index()
{
return View(new UserAddModel());
}
[HttpPost]
public ActionResult GetSearchResults(UserAddModel model)
{
if (ModelState.IsValid)
{
try
{
List<UserPrincipalDto> results =
_authentication.SearchUsers(
ConfigurationManager.AppSettings["DomainName"],
model.UserSearchCriteria.FirstName,
model.UserSearchCriteria.LastName,
model.UserSearchCriteria.Username);
model.SearchResults = results;
Session["UserAddModel"] = model;
return View("Index", model);
}
catch (Exception ex)
{
Logger.Log(ex, User.Identity.Name);
}
}
else
{
ModelState.AddModelError("", "Error!");
}
Session["UserAddModel"] = model;
return View("Index", model);
}
public ActionResult Save(string username)
{
UserAddModel model = Session["UserAddModel"] as UserAddModel;
UserEntity exists = repository.Get(u => u.Username == username).FirstOrDefault();
if (exists == null)
{
UserPrincipal userPrincipal =
_authentication.GetUserDetails(
ConfigurationManager.AppSettings["DomainName"],
username);
model.User = new UserEntity();
model.User.Id = userPrincipal.Guid.Value;
model.User.FirstName = userPrincipal.DisplayName.FullNameToFirstName();
model.User.LastName = userPrincipal.DisplayName.FullNameToLastName();
model.User.Email = userPrincipal.EmailAddress;
model.User.Username = userPrincipal.SamAccountName;
}
else
{
model.User = new UserEntity();
model.User.Id = exists.Id;
model.User.FirstName = exists.FirstName;
model.User.LastName = exists.LastName;
model.User.Email = exists.Email;
model.User.Username = exists.Username;
model.User.RoleId = exists.RoleId;
}
ViewBag.Roles = roles;
return View("Index", model);
}
[HttpPost]
public ActionResult Save(UserAddModel model)
{
UserEntity exists = repository.Get(u => u.Id == model.User.Id).FirstOrDefault();
if (exists == null)
{
Result result = repository.Save(model.User);
HandleResult(result, model);
}
else
{
Result result = repository.Save(model.User, PageMode.Edit);
HandleResult(result, model);
}
ViewBag.Roles = roles;
return View("Index", model);
}
}
}
As you see there are two different forms in my view and I'm storing the whole view model in Session in my controller. But I think this is not fine enough. What if session expires or what if I have to deploy my application using a load balancer?
What is the best way to develop this kind of page? I'm open to any kind of suggestions.
Thanks in advance,

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