How can I get the properties of the class? - class

hello I want to get the properties of the class as a dynamic
thank you
var result = GetAttributes("Student");
public class Student
{
public int StudentID { get; set; }
public string StudenName { get; set; }
public string StudenSurName{ get; set; }
public bool Active { get; set; }
List<Teacher> TeacherList { get; set; }
}
public class Teacher
{
public int TeacherID { get; set; }
public string TeacherName{ get; set; }
}

Related

Invalid column when adding a foreginkey

public class PIC
{
[Key]
public int Id { get; set; }
[ForeignKey("IMONumber")]
public int IMONumber { get; set; }
public string VesselName { get; set; }
public string PICOperation { get; set; }
public string PICChartering { get; set; }
}
public class VesselInfo
{
[Key]
public int Id { get; set; }
public string ImoType { get; set; }
public int IMONumber { get; set; }
public PIC PIC { get; set; }
}
When I call following:
var test1 = db.Vessels.ToList();
or
var test2 = db.Vessels.Include(p=>p.PIC).ToList();
I get an error saying PICId invalid column? And opointers?
i will recommend this:
Your PIC class is not connected with a foreign key your VeselInfo table so they are not related and you cannot get information about that. Try replacing your code and try again
public class PIC
{
[Key]
public int Id { get; set; }
public int IMONumber { get; set; }
[ForeignKey("IMONumber")]
public virtual IMON IMON
public string VesselName { get; set; }
public string PICOperation { get; set; }
public string PICChartering { get; set; }
}
public class VesselInfo
{
[Key]
public int Id { get; set; }
public string ImoType { get; set; }
public int IMONumber { get; set; }
public int PicId {get; set;}
[ForeignKey("PicId")]
public virtual PIC PIC { get; set; }
}

Code first one-to-many relationship with restraints

I have the following one-to-many database structure generated by code first. Many Buttons can be added with a relation back to a single GSMUnit. BtnNo should be unique (for every GSMUnitId), and shouldn't be duplicated. Currently it is possible to duplicate. how can i prevent this?
public class GSMUnit
{
public int Id { get; set; }
[MaxLength(20)]
public string Model { get; set; }
[MaxLength(40)]
public string GsmName { get; set; }
[MaxLength(40)]
public string TelephoneNum { get; set; }
public int GSMSiteId { get; set; }
public virtual GSMSite GSMSite { get; set; }
public virtual GSMSetting GSMSettings { get; set; }
public virtual ICollection<Button> Buttons { get; set; }
}
public class Button
{
public int Id { get; set; }
[MaxLength(30)]
public string Primary { get; set; }
[MaxLength(30)]
public string Divert1 { get; set; }
[MaxLength(30)]
public string Divert2 { get; set; }
[MaxLength(30)]
public string Divert3 { get; set; }
[MaxLength(20)]
public string AptNo { get; set; }
[MaxLength(10)]
public string Code { get; set; }
[MaxLength(4)]
public string DTO { get; set; }
[MaxLength(4)]
public string Timeband { get; set; }
[MaxLength(15)]
public string BtnNo { get; set; }
[MaxLength(20)]
public string AptName { get; set; }
public int GSMUnitId { get; set; }
public virtual GSMUnit GSMUnit { get; set; }
}
You can use the Index attribute for that:
public class Button
{
public int Id { get; set; }
[MaxLength(30)]
public string Primary { get; set; }
[MaxLength(30)]
public string Divert1 { get; set; }
[MaxLength(30)]
public string Divert2 { get; set; }
[MaxLength(30)]
public string Divert3 { get; set; }
[MaxLength(20)]
public string AptNo { get; set; }
[MaxLength(10)]
public string Code { get; set; }
[MaxLength(4)]
public string DTO { get; set; }
[MaxLength(4)]
public string Timeband { get; set; }
[MaxLength(15)]
public string BtnNo { get; set; }
[MaxLength(20)]
public string AptName { get; set; }
[Index(IsUnique = true)]
public int GSMUnitId { get; set; }
public virtual GSMUnit GSMUnit { get; set; }
}
But I recommend you to take a look on Fluent API. It's easier to configure in my opinion.

Entity framework navigation property is null

I have two models using Entity Framework.
public class Player
{
public int PlayerId { get; set; }
public string Name { get; set; }
public string Sex { get; set; }
public string Plays { get; set; }
public string FavouriteSurface { get; set; }
}
public class SinglesMatch
{
public int SinglesMatchId { get; set; }
public int Player1Id { get; set; }
public int Player2Id { get; set; }
public int PlayerIdWinner { get; set; }
public DateTime Date { get; set; }
public string Venue { get; set; }
public string Score { get; set; }
public List<Player> Players { get; set; }
}
I am using the below code to attempt to display the Name of the player, based on the PlayerId in the SinglesMatch model matching the PlayerID from the Player model.
#foreach (var item in #Model)
{
<ul id="Players" class="bg-success"></ul>
<br/>
<h3>Date - #Html.DisplayFor(#modelItem => item.Date)</h3>
<li>Venue - #Html.DisplayFor(#modelItem => item.Venue)</li>
<li>Player 1 - #Html.DisplayFor(#modelItem => item.Players.First(p => p.PlayerId == item.Player1Id).Name)</li>
<li>Player 2 - #Html.DisplayFor(#modelItem => item.Players.First(p => p.PlayerId == item.Player2Id).Name)</li>
<li>Score- #Html.DisplayFor(#modelItem => item.Score)</li>
}
Upon debugging, the navigation property is always showing as null when the model is retrieved from my repository.
Am I using the navigation property in the correct fashion ? is there a problem with my query ?
Edit to include DbContext:
public TennisTrackerContext() : base("name=TennisTrackerContext")
{
}
public DbSet<Player> Players { get; set; }
public DbSet<PlayerRecord> PlayerRecords { get; set; }
public DbSet<SinglesMatch> SinglesMatches { get; set; }
public DbSet<DoublesMatch> DoublesMatches { get; set; }
public DbSet<Venue> Venues { get; set; }
}
}
You need to add a bridge table. Sql will create this automatically but you won't have access to the variables unless you create it in c#.
public class Player
{
public int PlayerId { get; set; }
public string Name { get; set; }
public string Sex { get; set; }
public string Plays { get; set; }
public string FavouriteSurface { get; set; }
List<PlayerInMatch> Matches { get; set; }
public Player()
{
Matches = new List<PlayerInMatch>();
}
}
public class PlayerInMatch
{
public int Id { get; set; }
public int PlayerId { get; set; }
[ForeignKey("PlayerId")]
public Player Player { get; set; }
public int SinglesMatchId { get; set; }
[ForeignKey("SinglesMatchId")]
public SinglesMatch SinglesMatch { get; set; }
}
public class SinglesMatch
{
public int SinglesMatchId { get; set; }
public int PlayerIdWinner { get; set; }
public DateTime Date { get; set; }
public string Venue { get; set; }
public string Score { get; set; }
public List<PlayerInMatch> Players { get; set; }
public SinglesMatch()
{
Players = new List<PlayerInMatch>();
}
}
static void Main(string[] args)
{
var match = new SinglesMatch();
match.Players.Select(c => c.Player.Name);
}
You need to make your navigation property virtual to enable lazy/eager loading:
public class SinglesMatch
{
public int SinglesMatchId { get; set; }
public int Player1Id { get; set; }
public int Player2Id { get; set; }
public int PlayerIdWinner { get; set; }
public DateTime Date { get; set; }
public string Venue { get; set; }
public string Score { get; set; }
public virtual List<Player> Players { get; set; }
}
Also, did you define the relationship between SinglesMatch and Singles in fluent api?
EDIT: I see you don't have any relations mapped through annotations or fluent api whatsoever, I suggest you take a look at this:
https://msdn.microsoft.com/en-us/data/jj591617.aspx

Entity Framework [Key] tag not being recognised

I am getting warning errors of no key having been defined for each of my class library classes despite the fact that I have the [Key] tag and including the System.ComponentModel.DataAnnotations namespace, here is my context:
Context:
namespace Project.Data
{
public class ProjectContext : DbContext, IProjectContext
{
public ProjectContext(string connString)
: base(connString)
{
this.Configuration.LazyLoadingEnabled = true;
Database.SetInitializer<ProjectContext>(new ProjectInitializer());
this.Database.CreateIfNotExists();
this.Database.Initialize(true);
}
public IDbSet<Article> Article { get; set; }
public IDbSet<Brand> Brand { get; set; }
public IDbSet<Colour> Colour { get; set; }
public IDbSet<Customer> Customer { get; set; }
public IDbSet<CustomerCredit> CustomerCredit { get; set; }
public IDbSet<Delivery> Delivery { get; set; }
public IDbSet<DesignerTicket> DesignerTicket { get; set; }
public IDbSet<EuroRate> EuroRate { get; set; }
public IDbSet<Gift> Gift { get; set; }
public IDbSet<GZero> GZero { get; set; }
public IDbSet<InvoiceStock> InvoiceStock { get; set; }
public IDbSet<PrintOptions> PrintOptions { get; set; }
public IDbSet<Product> Product { get; set; }
public IDbSet<ProductLocation> ProductLocation { get; set; }
public IDbSet<Sale> Sale { get; set; }
public IDbSet<SaleAccount> SaleAccount { get; set; }
public IDbSet<SalesToWeb> SalesToWeb { get; set; }
public IDbSet<Shop> Shop { get; set; }
public IDbSet<Staff> Staff { get; set; }
public IDbSet<Ticket> Ticket { get; set; }
public IDbSet<Transfer> Transfer { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
}
}
}
Context Interface:
namespace Project.Data
{
public interface IProjectContext
{
IDbSet<Article> Article { get; set; }
IDbSet<Brand> Brand { get; set; }
IDbSet<Colour> Colour { get; set; }
IDbSet<Customer> Customer { get; set; }
IDbSet<CustomerCredit> CustomerCredit { get; set; }
IDbSet<Delivery> Delivery { get; set; }
IDbSet<DesignerTicket> DesignerTicket { get; set; }
IDbSet<EuroRate> EuroRate { get; set; }
IDbSet<Gift> Gift { get; set; }
IDbSet<GZero> GZero { get; set; }
IDbSet<InvoiceStock> InvoiceStock { get; set; }
IDbSet<PrintOptions> PrintOptions { get; set; }
IDbSet<Product> Product { get; set; }
IDbSet<ProductLocation> ProductLocation { get; set; }
IDbSet<Sale> Sale { get; set; }
IDbSet<SaleAccount> SaleAccount { get; set; }
IDbSet<SalesToWeb> SalesToWeb { get; set; }
IDbSet<Shop> Shop { get; set; }
IDbSet<Staff> Staff { get; set; }
IDbSet<Ticket> Ticket { get; set; }
IDbSet<Transfer> Transfer { get; set; }
}
}
[Key] decorated class example:
namespace Project.Data
{
public class Article
{
[Key]
public int ArticleID;
public bool IsCore;
public string Make;
public string Product;
public decimal Sale;
public string Department;
public string Scale;
public string Detail;
public DateTime InDate;
public decimal Reduce;
public bool IsOnSale;
public string VAT;
public bool IsOnWeb;
public string ProductCode;
public string Pick;
public string MemoDetail;
public string LOC;
public string ColourCode;
public bool StatusFlag;
public string Terminal;
}
}
Despite have the [Key] placed on Article I am getting the following message for the article class as shown below and this is repeated for each of the classes:
Project.Data.Article: : EntityType 'Article' has no key defined. Define the key for this EntityType.
Anyone see what I am doing wrong here? would be greatly appreciated
Define the members of your class as public properties as opposed to public variables like you have here, by including {get; set;} at the end of the declaration

Have a list of objects as a foreign key

If I have two classes:
public class Event
{
public int EventId { get; set; }
public string EventName { get; set; }
}
and
public class Dog
{
public int DogId { get; set; }
public string Name { get; set; }
public int Age { get; set; }
}
I would like for my event-class to be able to have a list of dog attached to it.
How can I make my event-class understand that I want it to be able to contain a list of dogs?
I am using entity framework. Thank you!
Assuming you're using Code-First:
public class Event
{
public int EventId { get; set; }
public string EventName { get; set; }
public virtual ICollection<Dog> Dogs { get; set; }
}
public class Dog
{
public int DogId { get; set; }
[ForeignKey("Event")]
public int EventID { get; set; }
public string Name { get; set; }
public int Age { get; set; }
public virtual Event Event { get; set; }
}