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Set interface us a properties c#

I've created three interfaces - IUser, ICostCenter, IDepartment. IUser and IDepartment are properties of ICostCenter.
public interface ICostCenter
{
IDepartment Department { get; set; }
User.IUser CostCenterHead { get; set; }
}
The class implementing ICostCenter will be used in the DbContext for my db.
public class tblCostCenter : WorkingInterface.Interface.Organization.ICostCenter
{
public tblCostCenter()
{
this.ID = Guid.NewGuid().ToString();
}
public string ID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
private WorkingInterface.Interface.User.IUser CostCenterHead { get; set; }
public string UserID { get; set; }
[ForeignKey("UserID")]
public Model.tblUser UserObject
{
get { return (Model.tblUser)this.CostCenterHead; }
set { this.CostCenterHead = value; }
}
private WorkingInterface.Interface.Organization.IDepartment Department { get; set; }
public string DepartmenID { get; set; }
[ForeignKey("DepartmenID")]
public Model.tblDepartment DepartmentObject
{
get { return (Model.tblDepartment)this.Department; }
set { this.Department = (Model.tblDepartment)value; }
}
}
I'm getting an error because I made the IUser and IDepartment properties private. How can I properly implement the interface? I want these properties to be hidden.

The interface is declared explicitly as public, that means that all the members declared in that interface MUST be public
So you need to declare both of these properties as public:
public WorkingInterface.Interface.User.IUser CostCenterHead { get; set; }
public WorkingInterface.Interface.Organization.IDepartment Department { get; set; }
NOTE: these have been declared as implicit implementations, so they are available to all contexts. If you want to hide them from general use, you can use explicit implementation.
Because you tried to use private accessibility, I assume you generally want to hide these properties from view, you can do this and still honor the interface contract by using explicit implementation syntax:
WorkingInterface.Interface.User.IUser ICostCenter.CostCenterHead { get; set; }
WorkingInterface.Interface.Organization.IDepartment ICostCenter.Department { get; set; }
They are still public but can only be accessed by first casting the object to the specific interface type explicitly.
tblCostCenter obj = new tblCostCenter();
...
// this wont work:
Console.WriteLine(obj.CostCenterHead);
// instead you will have to cast the object first
Console.WriteLine((obj as ICostCenter)).CostCenterHead);
// or if the local variable was an ICostCenter
ICostCenter costObj = obj;
Console.WriteLine(costObj.CostCenterHead);
...
// Pattern matching can also be helpful in these scenarios
if (obj is ICostCenter cc)
Console.WriteLine(cc.CostCenterHead);
If you want to use explicit declaration in your class you could try this:
WorkingInterface.Interface.User.IUser ICostCenter.CostCenterHead { get; set; }
public string UserID { get; set; }
[ForeignKey("UserID")]
public Model.tblUser UserObject
{
get { return ((ICostCenter)this).CostCenterHead as Model.tblUser; }
set { ((ICostCenter)this).CostCenterHead = value; }
}
WorkingInterface.Interface.Organization.IDepartment ICostCenter.Department { get; set; }
public string DepartmenID { get; set; }
[ForeignKey("DepartmenID")]
public Model.tblDepartment DepartmentObject
{
get { return ((ICostCenter)this).Department as Model.tblDepartment; }
set { ((ICostCenter)this).Department = value; }
}
this only works if:
Model.tblDepartment : IDepartment
Model.tblUser : User.IUser

Entity Framework map multiple level properties

I am trying to implement a hierarchical inheritance structure in Entity Framework, specifically for settings. For example, lets say we have user preferences:
public class StorePreference: Preference { }
public class UserPreference : Preference { }
public class Preference {
public string BackgroundColor { get; set; }
public ContactMethod ContactMethod { get; set; }
}
public enum ContactMethod {
SMS,
Email
}
I'd like it so that if I lookup the user's preferences. If the user doesn't exist or the property value is null, it looks up the parent (store) default preferences.
Ideally, i'd like it to work similar to abstract inheritance:
public class UserPreference : StorePreference {
private string _backgroundColor;
public string BackgroundColor {
get {
if (this._backgroundColor == null)
return base;
return this._backgroundColor;
}
set { this._backgroundColor = value; }
}
}
If I were to write this as a SQL query, it'd be a CROSS APPLY with a CASE statement:
SELECT
CASE WHEN User.BackgroundColor == null THEN Store.BackgroundColor ELSE User.BackgroundColor END BackgroundColor,
CASE WHEN User.ContactMethod == null THEN Store.ContactMethod ELSE User.ContactMethod END ContactMethod
FROM UserPreference User
CROSS APPLY StorePreference Store
WHERE UserPreference.UserId = #UserId
Is there a way I can achieve loading this in EF?

In your base class add default property values:
public class Preference {
public string BackgroundColor { get; set; } = "Red";
public ContactMethod ContactMethod { get; set; } = ContactMethod.SMS;
}
Something like this to set from database:
public class StorePreference : Preference { }
public class UserPreference : Preference { }
public class Preference {
public Preference() {
BackgroundColor = DefaultPreference.BackgroundColor;
ContactMethod = DefaultPreference.ContactMethod;
}
public string BackgroundColor { get; set; }
public ContactMethod ContactMethod { get; set; }
public DefaultPreference DefaultPreference { get; set; }
}
public class DefaultPreference {
public string BackgroundColor { get; set; }
public ContactMethod ContactMethod { get; set; }
}

As long as the properties are public, entity won't have a problem pulling the data from another table as the default. You would need to create a private field to hold the data if you used a setter:
public class ChildTable : EntityBase {
private string _someCategory;
[Key]
[Column(name: "CHILD_ID")]
public override int Id { get; protected set; }
[Column(name: "SOME_CATEGORY")]
public string SomeCategory {
get { return _someCategory; }
set { _someCategory = value ?? ParentTable.SomeCategory; }
}
[ForeignKey("ParentTable")]
[Column(name: "PARENT_ID")]
public int ParentTableId { get; set; }
public virtual ParentTable ParentTable { get; set; }
}
This is just an alternative to a constructor, if you need more control over the setter logic, otherwise Austin's answer would be simpler to implement

How to go about combining two objects, manipulate the data, then separate them?

I have two classes with some similar fields, some different, and a form that utilizes two different objects depending on what mode it's in (insert/edit).
Instead of using two different objects and if statements checking the form mode, I'd like to have one struct to be hydrated with either of the two objects fields so I can manipulate one object through the page life-cycle. Then separated the struct back to its respective object for insert/updating the DB.
Example of classes:
public partial class SomeClass
{
public Int32 B {get;set;}
public String C {get;set;}
public Boolean D {get;set;}
}
public class SomeOtherClass
{
public Int32 A {get;set;}
public Int32 B {get;set;}
public String C {get;set;}
}
Update with Solution Example:
public interface IInsertable
{
string SharedName { get; set; }
string SharedID { get; set; }
string editedFieldValue { get; set; }
long GetSuperSecreteInfo();
}
internal class InsertableImplementation : IInsertable
{
public string SharedName { get; set; }
public string SharedID { get; set; }
public string editedFieldValue { get; set; }
public long GetSuperSecreteInfo()
{
return -1;
}
}
public interface IUpdateable
{
string SharedName { get; set; }
string SharedID { get; set; }
string updatedFieldValue { get; set; }
Guid GenerateStevesMagicGuid();
}
internal class UpdateableImplementation : IUpdateable
{
public string SharedName { get; set; }
public string SharedID { get; set; }
public string updatedFieldValue { get; set; }
public Guid GenerateStevesMagicGuid()
{
return new Guid();
}
}
public static class WonderTwinFactory
{
public static WonderTwins GenerateWonderTwin(IUpdateable updateable, IInsertable insertable)
{
var wt = new WonderTwins();
// who will win?
wt.SharedID = updateable.SharedID;
wt.SharedID = insertable.SharedID;
// you decide?
wt.SharedName = updateable.SharedName;
wt.editedFieldValue = "stuff";
return wt;
}
}
public class WonderTwins : IInsertable, IUpdateable
{
public string SharedName { get; set; }
public string SharedID { get; set; }
public string editedFieldValue { get; set; }
public long GetSuperSecreteInfo()
{
return 1;
}
public string updatedFieldValue { get; set; }
public Guid GenerateStevesMagicGuid()
{
return new Guid();
}
}
class Program
{
static void Main(string[] args)
{
IUpdateable updateable = new UpdateableImplementation();
IInsertable insertable = new InsertableImplementation();
WonderTwins dualImplementatin = WonderTwinFactory.GenerateWonderTwin(updateable, insertable);
IUpdateable newUpdateable = dualImplementatin as IUpdateable;
IInsertable newInsertable = dualImplementatin as IInsertable;
}
}

Have both classes implement an interface that defines the operations common to each, including both the fields that are shared (assuming the view needs to access them) and also a method to actually perform the operation that they represent (insert/edit).

Other way of doing such things is using C# dynamic object and assign properties directly. It may help to avoid any new type or interface and directly utilizing new dynamic object any time, as much as required.
var newObject = new {
objectOfClass1 = x.prop1,
objectOfClass2 = x.prop2
}

Model property initialization

I have this model class "UserProfile", it's the original UserProfile class of Membership with a few added properties and methods.
[Table("UserProfile")]
public class UserProfile
{
public UserProfile()
{
this.DictionaryFrom = "eng";
this.DictionaryTo = "hun";
this.trainingType = "normal";
}
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
public string DictionaryFrom { get; set; }
public string DictionaryTo { get; set; }
public string trainingType { get; set; }
public virtual ICollection<ForeignExpression> learnedexpressions { get ; set ; }
}
My problem is that upon registering a new user, the three fields in the constructor don't get the values assigned to them (so, there's a NULL in the database for each of them).
The user can set them by choosing values from a list, but I'd like to have a default value for all of them. What am I doing wrong?

Not being a C# aficionado, I'd do something like this... there's probably a "better" way of doing it.
private string myValue = "default value";
public string MyValue {
get { return myValue; }
set {
if (null != value) { myValue = value; }
}
}

How to achieve Multiple inheritance in C#?

I have the below code in my Application.
public class GeneralInfo
{
private string _id;
private string _name;
public string id
{
set
{
_id = value;
}
get
{
return _id;
}
}
public string name
{
set
{
_name = value;
}
get
{
return _name;
}
}
}
public class SecureInfo
{
private string _password;
public string password
{
set
{
_password = value;
}
get
{
return _password;
}
}
}
public class User
{
}
I need to apply multiple inheritance in the above code ie. the classes GeneralInfo,SecureInfo properties should be accessible in the user class.
I know using interface Multiple inheritance can be achieved. But i need to define the properties in the base class which is restricted in Interface.
How I can achieve this?

C# does not support multiple inheritance. However you can achieve this via multiple interfaces.
public interface ISecureInfo
{
}
public interface IGeneralInfo
{
}
public class UserClass : ISecureInfo, IGeneralInfo {
}

You probably better off encapsulating the data in the class rather than trying to use something to do multiple inheritance here. See this question for some arguments for this.

You can achieve this through interface based inheritance:
public interface IGeneralInfo
{
String Id { get; set; }
String Name { get; set; }
}
public interface ISecureInfo
String Password { get; set; }
}
public class User : IGeneralInfo, ISecureInfo
{
// Implementation of IGeneralInfo
public String Id { get; set; }
public String Name { get; set; }
// Implementation of ISecureInfo
public String Password { get; set; }
}
Or, going one step further, through composition:
public interface IGeneralInfo
{
String Id { get; set; }
String Name { get; set; }
}
public class GeneralInfo : IGeneralInfo
{
public String Id { get; set; }
public String Name { get; set; }
}
public interface ISecureInfo
String Password { get; set; }
}
public class SecureInfo : IGeneralInfo
{
public String Password { get; set; }
}
public class User : IGeneralInfo, ISecureInfo
{
private GeneralInfo generalInfo = new GeneralInfo();
private SecureInfo secureInfo = new SecureInfo();
public String Id {
get { return generalInfo.Id; }
set { generalInfo.Id = value; }
}
public String Name {
get { return generalInfo.Name; }
set { generalInfo.Name = value; }
}
public String Password {
get { return secureInfo.Password; }
set { secureInfo.Password = value; }
}
}

From your sample description, encapsulation might be what you might want to use:
public class Info{
GeneralInfo general;
SecureInfo secure;
...
}

You cannot do multiple inheritance in C# because it is not supported like C++. In C# you can use interfaces for it and implement method and properties. For sample, you could have a base class
public abstract class Entity
{
public string Name { get; set; }
}
You also could have some interfaces:
public interface IPrint
{
void Print();
}
public interface IGenerate
{
void Generate();
}
And use it like multiples inheritance (but it is not, it is just a single inheritance and interfaces)
public class User : Entity, IPrint, IGenerate
{
public void Print()
{
// some code
// here you could access Name property, because it is on base class Entity
}
public void Generate()
{
// some code
}
}
And you could instance it using the abstractions:
Entity e = new User();
IPrint p = new User();
IGenerate g = new User();
User u = new User();
If you need implementations, you could do a hiearachy inherits, for sample:
User inherit from Person that inherit from Entity.
public class Entity
{
public int Id { get; set; }
public void Method()
{
// some code
}
}
public class Person : Entity
{
public string Name { get; set; }
public void AnotherMethod()
{
// some code
}
}
public class User : Person
{
public string Password { get; set; }
public bool CheckUser(string name, string passworkd)
{
// some code
}
}

I think the best would be to seperate the implementation of the interfaces and the real class you have at the end.
What I mean is something like the Bridge Pattern.
Your class (that will implement several interfaces) will just deleagte the method calls to the real implementation, that you can have in a seperate place and only once.

You could also use an approach like this. You would get to the same point than if you would be using multiple inheritance. That way, you could inherit only Entity if you don't need the SecureInfo stuff (i.e. for books and other stuff). Still, I think composition would do better in this case as others say...
class User : SecuredEntity { }
abstract class SecuredEntity : Entity, ISecureInfo
{
public string Password { get; set; }
}
abstract class Entity : IGeneralInfo
{
public string ID { get; set; }
public string Name { get; set; }
}
interface IGeneralInfo
{
string ID { get; set; }
string Name { get; set; }
}
interface ISecureInfo
{
string Password { get; set; }
}