I have a class:
public class TaskDiplayModel
{
public int taskId { get; set; }
[DisplayName("Task Description")]
public string description { get; set; }
[DisplayName("Priority")]
public string priority { get; set; }
[DisplayName("State")]
public string state { get; set; }
[DisplayName("Due By")]
public DateTime deadline { get; set; }
[DisplayName("Created By")]
public PersonObject created_by { get; set; }
[DisplayName("Assigned To")]
public PersonObject assigned_to { get; set; }
[DisplayName("Category")]
public string category { get; set; }
[DisplayName("Sub Category")]
public string subCategory { get; set; }
[DisplayName("Created")]
public DateTime createdDate { get; set; }
[DisplayName("Updated")]
public DateTime lastUpdatedDate { get; set; }
[DisplayName("Updated By")]
public PersonObject lastUpdatedBy { get; set; }
}
I then have another class which inherits from this class:
public class TaskModifyModel : TaskDiplayModel
{
public int priorityId { get; set; }
public int stateId { get; set; }
public int categoryId { get; set; }
public int subCategoryId { get; set; }
public SelectList states { get; private set; }
public SelectList priorities { get; private set; }
public SelectList categories { get; private set; }
public SelectList subCategories { get; private set; }
public TaskModifyModel()
{
SetupReferenceData(0);
}
public TaskModifyModel(int taskId)
{
var taskService = new TaskService();
var task = taskService.GetTask(taskId);
}
}
In my application, I create a TaskModifyModel object. However, string fields from the base class are null. I'd expect them to have been created and be String.Empty. But I get exception when I try to access them. Am I missing something?
These are MVC3 Models, by the way.... And code from the classes have been omitted as I think it's irrelevant to the question.
in .NET, the default value for a string is null, not String.Empty, so unless you specifically set the values of the properties to String.Empty, they will remain null.
Assuming you want your string properties to default to an empty string instead of null, you would normally do this either by setting them in the constructor:
public void TaskDiplayModel()
{
description = String.Empty;
priority = String.Empty;
state = String.Empty;
}
Or by using a field-backed property instead of an auto property, and setting the backing field:
private string _description = String.Empty;
[DisplayName("Task Description")]
public string description
{
get { return _description; }
set { _description = value; }
}
Personally I usually use the first option, doing it in the constructor, because it is less to code.
Just to add to rally25rs' excellent answer (+1 from me anyway), given the following abridged version:
public class TaskDiplayModel
{
private string _priority = string.Empty;
public int TaskId { get; set; }
public string Description { get; set; }
public string Priority
{
get { return _priority; }
set { _priority = value; }
}
public TaskDisplayMode()
{
Description = string.Empty;
}
}
public class TaskModifyModel : TaskDisplayMode
{
public int PriorityId { get; set; }
public TaskModifyModel()
:base()
{
PriorityId = 3;
}
}
Then the order upon construction of TaskModifyModel is as follows:
Set _priority to string.Empty, TaskId to 0, PriorityId to 0, and Description to null (if no value is stated, everything gets set to null if a reference, 0 if a number, and structs get set to having their fields full of 0 and null).
If the constructor body of TaskDiplayModel is executed, setting Description to string.Empty.
The constructor body of TaskModifyModel is executed, setting PriorityId to 3.
And so on if the nested inheritance is more complicated. As a rule, you can expect some of this to be optimised, so don't worry about whether it would be faster or slower to take a different approach as to how you set a value - it won't, except in debug runs. It does though explain the rule of avoiding calling virtual methods within constructors - most of the time we don't need to care about the ordering above and just treat the constructor as a single unit after which we have a fully constructed object, but if you start playing with virtual calls then the above ordering becomes very important because at one point PriorityId is 0, and at another its 3.
Related
I have a class like this
public class ListOfBMTTeamMapping
{
public class TeamMapping
{
public List<TeamMappings> results { get; set; }
}
public class TeamMappings
{
public int id { get; set; }
public string areaPath { get; set; }
public string agileReleaseTrainName { get; set; }
public string deliveryTeamName { get; set; }
public string keyedInTeamCode { get; set; }
public string deliveryTeamId { get; set; }
public bool isDeleted { get; set; }
public string modified { get; set; }
public string modifiedBy { get; set; }
}
}
And here is my model class to which I need the above API class to get copied
public class JsonBmtAdoMapping
{
public int? Id { get; set; }
public string AreaPath { get; set; }
public string AgileReleaseTrainName { get; set; }
public string DeliveryTeamName { get; set; }
public string KeyedInTeamCode { get; set; }
public string DeliveryTeamId { get; set; }
public string IsDeleted { get; set; }
public DateTime? Modified { get; set; }
public string ModifiedBy { get; set; }
}
So here is my code I tried
var format = "dd/MM/yyyy";
var dateTimeConverter = new IsoDateTimeConverter { DateTimeFormat = format };
ListOfBMTTeamMapping.TeamMapping Results = new ListOfBMTTeamMapping.TeamMapping();
Results = JsonConvert.DeserializeObject<ListOfBMTTeamMapping.TeamMapping>(responseBody);
List<JsonBmtAdoMapping> jM = new List<JsonBmtAdoMapping>();
jM = _mapper.Map<ListOfBMTTeamMapping.TeamMapping,List<JsonBmtAdoMapping>>(Results);
int n = 10;
And here is my automapper profile
CreateMap<ListOfBMTTeamMapping.TeamMapping, List<JsonBmtAdoMapping>>();
CreateMap<ListOfBMTTeamMapping.TeamMappings, JsonBmtAdoMapping>();
But when the code executes, Ofcourse I am getting the data in results variable without any trouble
But when the mapper code fires, it execute the line without any error, but no data being copied from source to my model class which is the destination
jM.count is always 0 when Results hold 124 rows of data
What I did wrong
Your mapping from TeamMapping to List<JsonBmtAdoMapping> can't be done out of the box by AutoMapper, because your source is an object with a property that contains the list and the destination is a list on itself.
So you have to tell him, how this conversion from a single object to a list can be done. Due to the fact, that you already have a mapping for each individual item, we can use that recursively within our mapping method.
By using this mapping, it should work:
CreateMap<ListOfBMTTeamMapping.TeamMappings, JsonBmtAdoMapping>();
CreateMap<ListOfBMTTeamMapping.TeamMapping, List<JsonBmtAdoMapping>>()
.ConvertUsing((src, _, context) => src.results.Select(context.Mapper.Map<JsonBmtAdoMapping>).ToList());
Update
Cause a mapper is already defined for the individual items and lists are handled automatically by AutoMapper we can even make it shorter (thanks for Lucian for the hint in the comments):
CreateMap<ListOfBMTTeamMapping.TeamMappings, JsonBmtAdoMapping>();
CreateMap<ListOfBMTTeamMapping.TeamMapping, List<JsonBmtAdoMapping>>()
.ConvertUsing((src, _, context) => context.Mapper.Map<List<JsonBmtAdoMapping>>(src.results));
Code without AutoMapper:
List<CountryDM> countryDMList = _countryRepo.GetCountry();
List<CountryVM> countryVMList = new List<CountryVM>();
foreach (CountryDM countryDM in countryDMList)
{
countryVMList.Add(CountryVM.ToViewModel(countryDM));
}
return countryVMList;
I used AutoMapper for the above task. But it returns a NULL list. Please refer the below code:
List<CountryDM> countryDMList = _countryRepo.GetCountry();
Mapper.CreateMap<List<CountryDM>, List<CountryVM>>();
List<CountryVM> countryVMList = new List<CountryVM>();
return Mapper.Map<List<CountryVM>>(countryDMList);
public class CountryDM
{
public int ID { get; set; }
public string CountryCode { get; set; }
public string Description { get; set; }
}
public class CountryVM
{
public int ID { get; set; }
public string CountryCode { get; set; }
public string Description { get; set; }
}
You don't need to define a mapping between lists, just between objects, AutoMapper will know how to extrapolate that:
Mapper.CreateMap<CountryDM, CountryVM>();
the rest stays the same
Lets assume I have a User class
public Class User
{
public string Name { get; set; }
public string Surname { get; set; }
public int Level {get;set;}
}
User user1 = new User();
user1.Name = "name";
user1.Surname = "Surname";
user1.Level = 0;
User user2 = new User();
user2.Name = "name";
user2.Surname = "Surname";
When I check user1.Level == user2.Level it returns true since default int value is 0.
So is there any way to do that I can understand that Level property of user2 is not set so that I can say these two are not identical?
1) If you use int? as type for Level, it will be NULL when not setted.
public Class User
{
public string Name { get; set; }
public string Surname { get; set; }
public int? Level {get;set;}
}
2) you can use the setter of the level attribute and set a boolean when you set a new value, if the other proposed solution is not good for you. Example:
public Class User
{
public string Name { get; set; }
public string Surname { get; set; }
private int _Level;
public int Level
{
get { return _Level; }
set { _Level= value; _hasLevel = true; }
}
public bool HasLevel { get { return _hasLevel; } }
}
Another option (in addition to the others suggested) is to set the value to something other than 0 in the class constructor. It's common to use -1.
public Class User
{
public User()
{
Level = -1;
}
public string Name { get; set; }
public string Surname { get; set; }
public int Level {get;set;}
}
Use Nullable
public Class User
{
public string Name { get; set; }
public string Surname { get; set; }
public int? Level {get;set;}
}
It will have by default value null instead of value 0.
for more about Nullable look at msdn documentation
You can change your class to make Level nullable.
public class User
{
public string Name { get; set; }
public string Surname { get; set; }
public int? Level {get;set;}
}
I'm trying to sort out this issue but as I'm learning a lot of this stuff as I go along I'd really appreciate it if someone could explain where I'm going wrong and/or some good resources where I can read up.
So, I have a model based on my Entity Framework model of my database and a viewmodel representing properties in that model. I've built a Kendo grid to display the data (defined in a js file) and the method in the contoller returns a Json result set. Trouble is, when I try to display a value in a joined db table, if there hasn't been a key value set, I get a nullreferenceexception error. Obviously I'm missing part of the puzzle here as there must be a way of coding this to stop it happening. Any help would be gratefully received!
My model is like this:
namespace TrainingKendoUI.Models
{
using System;
using System.Collections.Generic;
public partial class TRAINING_EMPLOYEE_COURSES
{
public int EMP_COURSE_ID { get; set; }
public int EMPLOYEE_ID { get; set; }
public int COURSE_ID { get; set; }
public Nullable<System.DateTime> DATE_ATTENDED { get; set; }
public Nullable<decimal> COURSE_COST { get; set; }
public string COURSE_RESITS { get; set; }
public Nullable<int> PROVIDER_ID { get; set; }
public Nullable<int> EMP_COURSE_STATUS_ID { get; set; }
public Nullable<int> VENUE_ID { get; set; }
public virtual TRAINING_COURSES TRAINING_COURSES { get; set; }
public virtual TRAINING_EMPLOYEE_COURSE_STATUS TRAINING_EMPLOYEE_COURSE_STATUS { get; set; }
public virtual TRAINING_EMPLOYEES TRAINING_EMPLOYEES { get; set; }
public virtual TRAINING_PROVIDERS TRAINING_PROVIDERS { get; set; }
public virtual TRAINING_VENUES TRAINING_VENUES { get; set; }
}
}
My controller method looks like this:
public JsonResult EmployeeCourses_Read()
{
var model = db.TRAINING_EMPLOYEE_COURSES;
var ViewModel = new List<EmployeeCoursesIntersectionViewModel>();
foreach (var employee in model)
{
ViewModel.Add(new EmployeeCoursesIntersectionViewModel(employee));
}
return Json(ViewModel, JsonRequestBehavior.AllowGet);
}
and my view model lilke this:
namespace TrainingKendoUI.ViewModels
{
public class EmployeeCoursesIntersectionViewModel
{
#region Constructors
public EmployeeCoursesIntersectionViewModel()
{
}
public EmployeeCoursesIntersectionViewModel(TRAINING_EMPLOYEE_COURSES model)
{
this.empCourseId = model.EMP_COURSE_ID;
this.employee = model.TRAINING_EMPLOYEES.FIRST_NAME;
this.course = model.TRAINING_COURSES.COURSE_NAME;
this.dateAttended = model.DATE_ATTENDED;
this.cost = model.COURSE_COST;
this.resits = model.COURSE_RESITS;
//These lines will produce a NullReference error if not set through the front end...
this.provider = model.TRAINING_PROVIDERS.PROVIDER_NAME;
this.status = model.TRAINING_EMPLOYEE_COURSE_STATUS.EMP_COURSE_STATUS;
this.venue = model.TRAINING_VENUES.VENUE_NAME;
}
#endregion
#region Properties
public int empCourseId { get; set; }
public string employee { get; set; }
public string course { get; set; }
public Nullable<System.DateTime> dateAttended { get; set; }
public Nullable<decimal> cost { get; set; }
public string resits { get; set; }
public string provider { get; set; }
public string status { get; set; }
public string venue { get; set; }
#endregion
}
}
Do a null check on the object before setting it, i.e.
this.provider = model.TRAINING_PROVIDERS == null ? ""
: model.TRAINING_PROVIDERS.PROVIDER_NAME;
and you'll have to do similar for status and venue
this.status = model.TRAINING_EMPLOYEE_COURSE_STATUS== null ? ""
model.TRAINING_EMPLOYEE_COURSE_STATUS.EMP_COURSE_STATUS;
this.venue = model.TRAINING_VENUES== null ? ""
model.TRAINING_VENUES.VENUE_NAME;
I'm encountering an issue using Silverlight4, Ria Services and Entity Framework.
From my sl client I try to get some data through ria services, in my domainService class this method gets called:
public IQueryable<LastMinuteWachtLijstPromotie> GetLastMinuteWachtLijstPromoties(){
IQueryable<LastMinuteWachtLijstPromotie> list = (IQueryable<LastMinuteWachtLijstPromotie>)this.ObjectContext.LastMinuteWachtLijstPromoties.Include("Promotie");
return (from LastMinuteWachtLijstPromotie lwmp in list where lwmp.Actief select lwmp);
}
when I check the contents of the list, in debug mode, it's filled with objects of type LastMinuteWachtLijstPromotie.
these objects have a navigation property to an Object named Promotie.
And i can access the properties of these Promotie objects.
On the silveright client however a method gets invoked when loading is complete:
public void OnLoadEntitiesCompleted(ServiceLoadResult<T> result) {
}
In this method I get all the requested LastMinuteWachtLijstPromotie objects as expected, the property
Promotie however is null.
I have set the [Include] tag on the property Promotie in the auto generated metadata class
and I use the .Include("Promotie")
These same methods are used for different objects from my Domain Model, this works perfectly.
Also, I cannot seem to find differences in the .edmx file with the database mappings and navigation properties.
Has anyone encountered the same issue or know a solution for it?
the metadata classes:
[MetadataTypeAttribute(typeof(LastMinuteWachtLijstPromotie.LastMinuteWachtLijstPromotieMetadata))]
public partial class LastMinuteWachtLijstPromotie
{
// This class allows you to attach custom attributes to properties
// of the LastMinuteWachtLijstPromotie class.
//
// For example, the following marks the Xyz property as a
// required property and specifies the format for valid values:
// [Required]
// [RegularExpression("[A-Z][A-Za-z0-9]*")]
// [StringLength(32)]
// public string Xyz { get; set; }
internal sealed class LastMinuteWachtLijstPromotieMetadata
{
// Metadata classes are not meant to be instantiated.
private LastMinuteWachtLijstPromotieMetadata()
{
}
public int AlertId { get; set; }
public string ArtikelNummer { get; set; }
public Nullable<int> ArtikelVariant { get; set; }
public int LastMinuteWachtLijstPromotieId { get; set; }
[Include]
public Promotie Promotie { get; set; }
public int PromotieArtikelId { get; set; }
public int PromotieId { get; set; }
public bool Actief { get; set; }
public DateTime Aanmaakdatum { get; set; }
}
}
[MetadataTypeAttribute(typeof(Promotie.PromotieMetadata))]
public partial class Promotie
{
// This class allows you to attach custom attributes to properties
// of the Promotie class.
//
// For example, the following marks the Xyz property as a
// required property and specifies the format for valid values:
// [Required]
// [RegularExpression("[A-Z][A-Za-z0-9]*")]
// [StringLength(32)]
// public string Xyz { get; set; }
internal sealed class PromotieMetadata
{
// Metadata classes are not meant to be instantiated.
private PromotieMetadata()
{
}
public string ActieType { get; set; }
public string AssortimentsManagerNaam { get; set; }
public string AssortimentsManagerTeamIds { get; set; }
[Display(Name = "Commerciele tekst")]
[Required(ErrorMessageResourceName = "Required", ErrorMessageResourceType = typeof(Nokavision.ReclameFolder.UI.Web.Resources.ValidationResources))]
public string CommercieleTekst { get; set; }
[Display(Name = " ")]
public string CommercieleTekstDetails { get; set; }
[Include]
public Frame Frame { get; set; }
public Nullable<int> FrameId { get; set; }
public Nullable<DateTime> LastMinuteWijzigingsDatum { get; set; }
public string Opmerkingen { get; set; }
[Display(Name = "Op wachtlijst")]
public Nullable<bool> OpWachtLijst { get; set; }
//public Nullable<int> PromotieCopyId { get; set; }
public int PromotieId { get; set; }
[Include]
public EntityCollection<PromotieLeverancier> PromotieLeveranciers { get; set; }
[Include]
public EntityCollection<PromotieMutatie> PromotieMutaties{ get; set; }
//public Nullable<int> PromotieOrigineleId { get; set; }
[Include]
public EntityCollection<PromotieSymbool> PromotieSymbolen { get; set; }
public string Status { get; set; }
[Display(Name = "Promotie inhoud")]
public string PromotieInhoud { get; set; }
[Display(Name = "Promotie eenheid")]
public string PromotieEenheid { get; set; }
[Display(Name = "Promotie prijs")]
public decimal PromotiePrijs { get; set; }
}
}
Add the Composition attribute to the property Promotie property of the LastMinuteWachtLijstPromotieMetadata class. Then it should work.
public partial class LastMinuteWachtLijstPromotie {
internal sealed class LastMinuteWachtLijstPromotieMetadata{
[Include]
[Composition]
public Promotie Promotie { get; set; }
}
}
I know this is an older thread and it may well have been answered elsewhere but I just stumbled upon it and since nobody has provided a link or a better answer.
I'm currently using Silverlight 5 and this is what worked for me (I think the process is the same in SL4 IIRC).
When propegating navigation properties to the client you need to tell RIA services that there is a relationship somewhere using the [Key] and [Association] attributes, this, not unlike the entity framework just describes how to map the relationship to the proper object.
First the metadata classes:
[MetadataTypeAttribute(typeof(Category.CategoryMetadata))]
public partial class Category
{
internal sealed class CategoryMetadata
{
private CategoryMetadata() {
}
[Key]
public int Id { get; set; }
public string NAME { get; set; }
[Association("CategoryToProducts", "Id", "CAT")]
[Include]
public EntityCollection<Product> Products { get; set; }
}
}
[MetadataTypeAttribute(typeof(Order.OrderMetadata))]
public partial class Order
{
internal sealed class OrderMetadata
{
// Metadata classes are not meant to be instantiated.
private OrderMetadata() {
}
[Key]
public int Id { get; set; }
public int PRODID { get; set; }
public DateTime DATE { get; set; }
public bool DONE { get; set; }
public int QTY { get; set; }
[Association("OrderToProduct", "PRODID", "Id", IsForeignKey = true)]
[Include]
public Product Product { get; set; }
}
}
[MetadataTypeAttribute(typeof(Product.ProductMetadata))]
public partial class Product
{
internal sealed class ProductMetadata
{
private ProductMetadata() {
}
[Key]
public int Id { get; set; }
public int CAT { get; set; }
public string NAME { get; set; }
public string DESC { get; set; }
public decimal PRICE { get; set; }
public int QTY { get; set; }
public long UPC { get; set; }
[Association("ProdToCat", "CAT", "Id", IsForeignKey = true)]
[Include]
public Category Category { get; set; }
[Association("ProductToOrders", "Id", "PRODID")]
[Include]
public EntityCollection<Order> Orders { get; set; }
}
}
Now we need to tell RIA services we want it to load the association:
(Note: Intellisense says it's a dot separated list of property names to include, however I tried something like .Include("Category.SubCategory") and this failed with an exception... though .Include("Category").Include("SubCategory") worked like a charm!)
public IQueryable<Product> GetProducts() {
return this.ObjectContext.Products.Include("Category");
}
I can now access my "Category" property from the Silverlight client and it is not NULL :)
Same as SilverX: just had the issue, solved it and thought it could be useful to someone.
I too had all the configuration stuff correct ([Include] for RIA S, Include() for EF) but a navigation property was still null on the Silverlight side.
Turns out the domain service method was using the [Invoke] attribute (and returning a IEnumerable<T>). Removing this attribute solved the issue.
(just for the record, [Invoke] was being used because the method had a List<Entity> parameter)