I am working with AutoMapper, which I am relatively new with, and I stumbled upon a small mapping problem I was hoping the community could assist with.
So I have two data transfer objects:
public class UserDto {
public string UserName { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public List<CharacterDto> Characters { get; set; }
}
public class CharaterDto {
public string CharacterName { get; set; }
public string ClassName { get; set; }
public int CharacterLevel { get; set; }
}
and two Domain Entities
public class Character {
public int ID { get; set; }
public int UserId { get; set; }
public string CharacterName { get; set; }
public string ClassName { get; set; }
public int CharacterLevel { get; set; }
}
public class User {
public int ID { get; set; }
public string UserName { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
The end goal is to be able to save the data taken in by the DTOs into the database via the Domain Entities; however, when it comes to typing up the list of Characters for 'UserDto', I do not know how to map this properly with AutoMapper. I can map it manually with little to no problems... but I can't find anything that helps to explain this or any examples that would help me understand it better.
I have tried doing things like:
CreateMap<UserDto, Character>()
.ForMember(dest => dest.CharacterName, m => m.MapFrom(source => source.Characters[0].CharacterName));
However, this seems to only map the 1st entry and not the others. I have also considered mapping the individual mappings like so:
CreateMap<CharacterDto, Character>();
CreateMap<UserDto, Character>()
.ForMember(?/*this section I cannot figure out*/)
But can't figure out how to associate the the collection of characters to the mapped CharacterDto. I doubt that if I run the code without that association, the code is going to automatically understand that for each character in characters, map each character using the appropriate mapper... If I must manually do this, I can... but if there is an AutoMapper way, any help constructing it would be greatly appreciated.
Type converters are you friend here for mapping 1 to many like this.
Let me know if you need me to go further and get you a working example from your models.
https://stackoverflow.com/a/18096914/7911333
Related
I am trying to write mapping configuration for next case. I have domain object:
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public string ImagePath { get; set; }
public virtual ICollection<Service> Services { get; set; }
public int? SubcategoryId { get; set; }
[ForeignKey("SubcategoryId")]
public virtual Category Subcategory { get; set; }
}
And Dto to map:
public class CategoryDto
{
public int Id { get; set; }
public string Name { get; set; }
public string ImagePath { get; set; }
}
The problem is, target class have less properties, than source. If I use simple map, I get an exception.
Mapper.Initialize(n => n.CreateMap<Service, ServiceDto>());
I can't use Ignore(), because it will be applied to target class, not source one. Method ForSourceMember() also didn't help for some reason. I read this question, it's fine for most cases, but property Services is not null, it's Count = 0, when it's empty. I also read some similar questions from the right, but they didn't help, maybe they worked in previous versions.
Hope someone can help me to find solution, or explain what I missed.
Mapper.Initialize can only be called once, when your app initializes itself, not per request as you're doing now.
After trying to execute the following query:
List<CourseLesson> courseLessons = (from cl in context.CourseLessons
.Include(x => x.CourseLessonTestQuestions)
select cl).ToList();
I get the the error Invalid column name 'CourseLesson_Id'.
My models and DataContext looks like this(this is from a test project I've created to repreduce the problem)
public class CourseLesson
{
public int Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public ICollection<CourseLessonTestQuestion> CourseLessonTestQuestions { get; set; }
}
public class CourseLessonTestQuestion
{
public int Id { get; set; }
public int CourseLessonId { get; set; }
[ForeignKey(nameof(CourseLessonId))]
public CourseLesson CourseLesson { get; set; }
public int? ReturnCourseLessonId { get; set; }
[ForeignKey(nameof(ReturnCourseLessonId))]
public CourseLesson ReturnCourseLesson { get; set; }
}
I have 2 foreign keys that point to the same table and I'm assuming EF is trying to create or map something that doesn't really exist.
After reading for a while I've found a way to fix my problem in (this answer) with the following code:
modelBuilder.Entity<CourseLessonTestQuestion>()
.HasOptional(cltq => cltq.ReturnCourseLesson)
.WithMany(x => x.CourseLessonTestQuestions);
What really bugs me about this situation is why everything works when I use the Fluent API, but it doesn't work with the ForeignKey attribute? This looks like something that could lead to future problems and I want to know what is really happening.
And the real question is there a solution for fixing this problem without the Fluent API? Like using attributes or some other convention?
I'm using Entity Framework 6.1.3
Solution without Fluent API, but with the help of InversePropertyAttribute, whose constructor's argument is the name of corresponding CourseLessonTestQuestion's property:
public class CourseLesson
{
public int Id { get; set; }
public string Title { get; set; }
public string Content { get; set; }
[InverseProperty("CourseLesson")]
public ICollection<CourseLessonTestQuestion> CourseLessonTestQuestions { get; set; }
[InverseProperty("ReturnCourseLesson")]
public ICollection<CourseLessonTestQuestion> ReturnCourseLessons { get; set; }
}
I am learning how to use MVC right now and I just have a question on when I am creating and updating entries in the database. I was reading a post from this page: asp.mvc 4 EF ActionResult Edit with not all fields in view
The guy in it said to create a model that will be used, so is the efficient way to insert a new row and update an existing row by having two models with different properties?
So my models would look like this -
public class UserModelView
{
public string FirstName { get; set; }
public string Surname { get; set; }
public DateTime AccountCreated { get; set; }
public DateTime? LastLoggedIn { get; set; }
}
public class UserModelCreate
{
[Key]
public int UserId { get; set; }
public string FirstName { get; set; }
public string Surname { get; set; }
public DateTime AccountCreated { get; set; }
}
public class UserModelUpdate
{
public string FirstName { get; set; }
public string Surname { get; set; }
public DateTime? LastLoggedIn { get; set; }
}
Is this the best way to do what I need to do?
Im guessing you were previously using the entity class when binding your model back in.
You shouldn't do that!
The guy in the post is right, this is a much better way of controlling your entity and model information and provides a layer of seperation between the two.
After all you wouldnt want a user being able to directly manipulate an entity via a HTTP request.
I answered something similar here
I have the following classes:
public class Problem
{
public Problem()
{
this.Questions = new HashSet<Question>();
this.Solutions = new HashSet<Solution>();
}
public int ProblemId { get; set; }
public string Title { get; set; }
public string Note { get; set; }
public virtual ICollection<Question> Questions { get; set; }
public virtual ICollection<Solution> Solutions { get; set; }
}
public class Question
{
public int QuestionId { get; set; }
public int ProblemId { get; set; }
public int QuestionStatusId { get; set; }
public string Note { get; set; }
public virtual Problem Problem { get; set; }
}
public class Solution
{
public int SolutionId { get; set; }
public int Number { get; set; }
public int ProblemId { get; set; }
public bool? Correct { get; set; }
public string Text { get; set; }
public string Note { get; set; }
public virtual Problem Problem { get; set; }
}
Can someone help me with LINQ for my EF6,1 SQL Server 2012.
What I would like to do is to get a List that contains only a subset of the data. In this case I would like the Notes properties in Problem, Question and Solution Entities to not be fetched from the database.
Note the Question and Solution tables are connected to the Problem table. I'm not 100% sure of this but I think this means I don't need to add an .Include.
Ideally I would like the selects that EF causes to be issues to not include the Notes column.
You can use table splitting feature of EF. Create a Problem(PK+all fields except for Notes) and a ProblemNotes(PK+Notes) entities. Then querying against Problem should satisfy your needs.
http://msdn.microsoft.com/en-us/data/jj715645.aspx
With Entity Framework table splitting you can separate the properties that might contain very large amount of data into a separate entity and only load it when required.
You might use .Select(...) to make avoid fetching redundantly data from db. The code below illustrates how to fetch list of Problems with only ProblemId and Title fields:
var result = context.Problems.Select(problem => new { ProblemId = problem.ProblemId , Title = proble.Title }).ToList();
Using of .Select above will generate SQL query "SELECT p.ProblemId,p.Title from dbo.Problems as p".
Using of .List will retrieve data (it will not be dependent on context anymore )
Your might cast resulted set to Problem type ,eg:
var newResult = result.Select(x=>new Problem() { ProblemId = x.ProblemId, Title = x.Title } )
I'm trying to map the results of a stored procedure into a model that contains another model several times. I'm not sure if this is possible, but wanted to ask and see if this is a valid approach, or if it would be better to define everything out individually.
My model classes look like this:
public class ClientSummary {
public virtual int Id { get; set; }
public virtual int Client_ID { get; set; }
public virtual string Client_Name { get; set; }
public virtual string State { get; set; }
public virtual EDITotal Totals { get; set; }
public virtual EDITotal In_Totals { get; set; }
public virtual EDITotal Out_Totals { get; set; }
public virtual EDITotal Direct_Totals { get; set; }
public virtual EDITotal CPN_Totals { get; set; }
}
public class EDITotal {
public virtual int Count { get; set; }
public virtual double Charges { get; set; }
public virtual double StateSavings { get; set; }
public virtual double PPOSavings { get; set; }
public virtual float PPO_Pct_Bill { get; set; }
public virtual float PPO_Pct_State { get; set; }
public virtual int Unique_TaxIds { get; set; }
}
What I'm not sure of is what my class map would look like in Fluent NHibernate, or if something like this is possible. I'm mainly trying to keep things tidy, and reusable. I'm sure I'll have other reports that will use similar metrics. Am I going about this the right way, or do I really need to define a full model for each report I build? This is all taking place inside a MVC Web application.
Thanks in advance!
Yes this is indeed possible and right or wrong you can get it working with the way you have your classes setup. To do this, you can use a mapper like this:
public class ClientSummaryMappingOverride : IAutoMappingOverride<ClientSummary>
{
public void Override(AutoMapping<ClientSummary> mapping)
{
mapping.References(x => x.Totals, "Totals_id");
mapping.References(x => x.In_Totals, "In_Totals_id");
mapping.References(x => x.Out_Totals, "Out_Totals_id");
mapping.References(x => x.Direct_Totals, "Direct_Totals_id");
mapping.References(x => x.CPN_Totals, "CPN_Totals_id");
}
}
Once you have your map configured, you just need to make sure your Stored Procedure or SQL Query returns the ClientSummary records with the appropriate "Totals_id" type fields. NHibernate will pick up those ids and map them to the correct data (Lazy Load I believe, depending on your conventions or other mappings).