Hey I have a problem with my code.
Sorry if the question is too easy but I can't find a solution.
I have an object called user in class 1
The Object User has this variables.
public class User
{
public string email { get; set; }
public string password { get; set; }
public string mobilenumber { get; set; }
public string service { get; set; }
public override string ToString()
{
return $"{email}: {password}: {mobilenumber}: {service}";
}
}
These variables are filled with data in class 1
Now I want to access these data in class 2 and display them to me.
I tried something like
Class Firstclass{
public void OnLogin(){
public User user = new User();
user.email = abc#abc.com
}
}
Class B{
protected override async Task OnInitializedAsync(){
Firstclass firstclass = new Firstclass();
string output = firstclass.user.email;
}
}
There are several ways to do that. A simple one would be to instantiate the User inside the constructor:
public Class Firstclass
{
User user;
public FirstClass()
{
this.user = new User();
this.user.email = "abc#abc.com";
// more data could be here or use a local method to fill user's fields
}
public User
{
get
{
return this.user;
}
set
{
this.user = value;
}
}
}
Try to avoid using a public field, rather use a public property like User in above. Then in Class B, you would have:
Class B
{
protected override async Task OnInitializedAsync()
{
Firstclass firstclass = new Firstclass();
string output = firstclass.User.email;
}
}
Related
there is a concept about inheritance which I do not quite understand.
I have a
protected DeveloperReport DeveloperReport; // Field
Wouldn't PersonalInfoBuilder be able to access that field ?
If yes,
public PersonalInfoBuilder MyPersonalInfo => new PersonalInfoBuilder(DeveloperReport);
Why do I still have to pass the DeveloperReport(field) into PersonalInfoBuilder constructor, when I can
just modify the protected DeveloperReport field by calling new PersonalInfoBuilder(), instead of
new PersonalInfoBuilder(DeveloperReport)?
And, how the concept of "return this" return the changes made to DeveloperReport(field) back to
DeveloperReportBuilder?
Thanks !
class DeveloperReport
{
// Properties
public int Id { get; set; }
public string Name { get; set; }
public DeveloperLevel Level { get; set; }
public int WorkingHours { get; set; }
public int HourlyRate { get; set; }
// Methods
public double CalculateSalary() => WorkingHours * HourlyRate;
}
class DeveloperReportBuilder
{
protected DeveloperReport DeveloperReport;
public PersonalInfoBuilder MyPersonalInfo => new PersonalInfoBuilder(DeveloperReport);
public DeveloperReportBuilder()
{
DeveloperReport = new DeveloperReport();
}
// return developer report.
public DeveloperReport Build() => DeveloperReport;
}
class PersonalInfoBuilder : DeveloperReportBuilder
{
public PersonalInfoBuilder(DeveloperReport report)
{
DeveloperReport = report;
}
public PersonalInfoBuilder()
{
}
public PersonalInfoBuilder NameIs(string name)
{
DeveloperReport.Name = name;
return this;
}
public PersonalInfoBuilder IDis(int id)
{
DeveloperReport.Id = id;
return this;
}
}
You only have to pass the report instance if you want to have both instances of DeveloperReportBuilder and PersonalInfoBuilder have acces to the same instance of DeveloperReport.
Inheritance will not copy the instance values.
I am new to generics and just wondering if it's possible to avoid the casting in the following code using better OO approach.
public class CollectorFactory
{
public static MyCollector Create(ICredential credential)
{
return new MyCollector(credential);
}
}
public class MyCollector {
public MyCredential Credential { get; set; }
public MyCollector(ICredential credential)
{
this.Credential = (MyCredential)credential;
}
public void Show()
{
Console.WriteLine(this.Credential.Username);
Console.WriteLine(this.Credential.AuthToken);
}
}
public class MyCredential : ICredential
{
public string Username{ get; set; }
public string AuthToken { get; set; }
}
public interface ICredential
{
}
Is there a way to save the casting of ICredential to MyCredential in MyCollector's Constructor? I don't have option to put Username and AuthToken in ICredential as it's implemented by two different Credentials that both have different set of properties. CollectorFactory will be returning different MyCollector instances in the future and both need to have different credentials.
Any help would be really appreciated.
I don't think it's possible given that you're implementing different credentials and trying to use them for ICredential as well.
Here is a way of doing this using generics. Please read my comments in the code.
public class CollectorFactory<T>
{
public T Create(ICredential credential)
{
return (T)Activator.CreateInstance(typeof(T), credential);
}
}
public class MyCollector : BaseCollector
{
public dynamic Credential { get; private set; }
public MyCollector(ICredential credential)
: base(credential)
{
this.Credential = credential;
}
// Having this method here limits your ability to make it more generic.
// Consider moving this to MyCredential since it refers to specific properties in MyCredential.
// If that is not what you want, then you must do a type check before calling methods/ accessing props in Credentials.
public void Show()
{
Console.WriteLine(this.Credential.Username);
Console.WriteLine(this.Credential.AuthToken);
}
}
public class MyCredential : ICredential
{
public string Username { get; set; }
public string AuthToken { get; set; }
}
public abstract class BaseCollector : ICredentialCollector
{
protected BaseCollector(ICredential credential)
{
if (credential == null)
{
throw new ArgumentNullException(nameof(credential));
}
}
}
public interface ICredentialCollector
{
}
public interface ICredential
{
}
// test implementation
public class TestClass
{
public void AuthFactoryTest()
{
// test auth instance
MyCredential auth = new MyCredential() {AuthToken = "asfgasdgdfg", Username = "xuser"};
// Create test factory
var fact = new CollectorFactory<MyCollector>();
var myCollector = fact.Create(auth);
// Do what you need to do to collector object
myCollector.Show();
}
}
Generics isn't the solution in this case. The issue here is that your factory is returning a specific type (MyCollector). A solution around this would be the following:
public class CollectorFactory
{
public static ICollector Create(MyCredential credential)
{
return new MyCollector(credential);
}
public static ICollector Create(OtherCredential credential)
{
return new OtherCollector(credential);
}
}
public interface ICollector
{
void Show();
}
public class MyCollector : ICollector
{
public MyCredential Credential { get; set; }
public MyCollector(MyCredential credential)
{
this.Credential = credential;
}
public void Show()
{
Console.WriteLine(this.Credential.Username);
Console.WriteLine(this.Credential.AuthToken);
}
}
public class MyCredential : ICredential
{
public string Username{ get; set; }
public string AuthToken { get; set; }
}
public interface ICredential
{
}
The above is pretty much the canonical example of the Factory design pattern.
Instead of overloads you could also do typechecking in the factory:
public class CollectorFactory
{
public static ICollector Create(ICredential credential)
{
if(credential.GetType() == typeof(MyCredential))
return new MyCollector((MyCredential) credential);
if(credential.GetType() == typeof(OtherCredential ))
return new OtherCollector((OtherCredential ) credential);
}
}
I am new in programming and trying to learn singleton but stuck in somewhere.
Here is my user class:
public class User
{
private static User user;
private User()
{
}
private int id;
public int Id
{
get { return id; }
set { id = value; }
}
private string isim;
public string Isim
{
get { return isim; }
set { isim = value; }
}
private string soyad;
public string Soyad
{
get { return soyad; }
set { soyad = value; }
}
public static User CreateUser()
{
if (user == null)
user = new User();
return user;
}
}
In my web form I tried this:
User myuser = User.CreateUser();
to create an object but it gives me an error like there is nothing as CreateUser()..What am I doing wrong
All you have to do is like following:
You have to modify The User class to make it like this
public class User
{
public int Id { get; set; }
public string Isim { get; set; }
public string Soyad { get; set; }
public class User(){}
public User(int id, string isim, string soyad)
{
Id = id;
Isim = isim;
Soyad = soyad;
}
}
Then you implement Singleton (user buisiness logic) class like this
using System;
public sealed class UserBusiness
{
private static volatile UserBusiness instance;
private static readonly object syncRoot = new Object();
private UserBusiness() { }
public static UserBusiness Instance
{
get
{
if (instance == null)
{
lock (syncRoot)
{
if (instance == null)
instance = new UserBusiness();
}
}
return instance;
}
}
public void AddUser(User userToAdd)
{
//TODO use your ORM or whatever to acces database and add the user
//for example if you use entityFramework you will need to do
//Context.Customers.Add(user)
//Context.SaveChanges();
//Just For Example
}
}
There are many implementation of singleton like mentioned in this MSDN article
and finally in your webForm Code you put the following :
var newUser = new User(1, "user1Isim", "user1Soyad");
UserBusiness.Instance.AddUser(newUser);
After All, there are many ways to do this, depends on your needs. I found this as the simpliest way to explain.
I've no experience of using C# but as part of one of our college modules we have to create a slot machine application. We created a Gambler class and I have to make a CheckBalance class where I will call the Token method from the Gambler class. But I get the error that is mentioned in the thread title.
Int tokens = Gambler.Tokens;
The above line is where I am getting my error.
This is my code:
enter code herenamespace CasinoClasslibrary
{
public class Gambler
{
public string Name { get; private set; }
public int Age { get; private set; }
public long CreditCardNum { get; private set; }
public int Tokens { get; public set; }
public string Username { get; private set; }
public string Password { private get; public set; }
public Gambler(string Name, int Age, long CreditCardNum, int Tokens, string Username, string Password)
{
this.Name = Name;
this.Age = Age;
this.CreditCardNum = CreditCardNum;
this.Tokens = Tokens;
this.Username = Username;
this.Password = Password;
}
}
public class Cashout : Gambler
{
public Boolean CheckBalance()
{
int tokens = Gambler.Tokens;
return true;
}
}
}
Since you are inheriting from Gambler I suspect that you need to access base.Tokens like:
public Boolean CheckBalance()
{
int tokens = base.Tokens; //here
return true;
}
Otherwise since Toakens is an instance member you have to create object of Gambler and then access it.
There are other errors in your code as well. You haven't defined a default (parameter less) constructor in your base class and you need to call the existing base constructor in your child class.
public class Cashout : Gambler
{
public Cashout()
: base("",0, 0, 1, "", "") //something like this
{
}
public Boolean CheckBalance()
{
int tokens = base.Tokens;
return true;
}
}
Because Cashout inherits from Gambler you can just do this. This is because the Cashout instance will have a Tokens property as well.
public class Cashout : Gambler
{
public Boolean CheckBalance()
{
int tokens = Tokens;
return true;
}
}
However, if you intended the method to be static, you will need an instance of Gambler to access that property and this should be passed into the static method as such.
public class Cashout : Gambler
{
public static Boolean CheckBalance(Gambler myGambler)
{
int tokens = myGambler.Tokens;
return true;
}
}
Finally, if you intended this Tokens property to be static itself, you need to declare it as such
public static int Tokens;
You may also want a static constructor to set it up.
Tokens is not static method but you try to access it through static construct (class level).
can make this work by declaring it static (although that's not likely what you want)
public static int Tokens { get; public set; }
or by instantiating Gambler
new Gambler().Tokens;
I am new to C# and am working on classes and understanding them. My problem is I am not understanding how to create a Get to retrieve the private variable _yourname and Set to set the private variable _yourname.
namespace WindowsFormsApplication1
{
class InputClass
{
private string _yourName;
public string _banner;
public virtual void GetInfo();
public InputClass(String _banner)
{
_banner = "Enter your name";
}
}
}
Maybe I am using the wrong function to GetInfo. But I am also wondering when I have the GetInfo if in the () I should write _yourname in it.
In C# there are properties, which have the function of public getter and setter methods in other languages:
class InputClass
{
private string _yourName;
public string _banner;
public InputClass(String _banner)
{
this._banner = _banner;
}
public string YourName
{
get { return _yourName; }
set { _yourName = value; }
}
}
But you can use auto properties, if you want:
class InputClass
{
public InputClass(String _banner)
{
Banner = _banner;
}
public string YourName
{
get; set;
}
public string Banner
{
get; set;
}
}
It sounds like you are trying to provide access to the _yourName field. If so then just use a property
class InputClass {
public string YourName {
get { return _yourName; }
set { _yourName = value; }
}
...
}
Now consumers of InputClass can access it as if it were a read only field.
InputClass ic = ...;
string yourName = ic.YourName;
ic.YourName = "hello";
Note: C# provides a special syntax for simple properties like this which are just meant to be wrappers over private fields. It's named auto-implemented properties
class InputClass {
public string YourName { get; set; }
}
You can override getters and settings using the get and set keywords. For example:
class InputClass
{
private string _yourName;
private string _banner;
public YourName
{
get { return _yourName; }
set { _yourName = value; }
}
public Banner
{
get { return _banner; }
set { _banner = value; }
}
public InputClass(String banner)
{
_banner = banner;
}
}
1.) Use properties instead of members, you get a free accessor (get) and mutator (set).
public string YourName { get; set; }
public string Banner { get; set; }
2.) You can take advantage of the default constructor, and declare it on the fly.
//the old way:
InputClass myClass = new InputClass();
myClass.YourName = "Bob";
myClass.Banner = "Test Banner";
//on the fly:
InputClass myClass = new InputClass()
{
YourName = "Bob",
Banner = "Test Banner"
}