Develop Reference

How can i Access a private variable in another class in C#

I wrote the code below and i want to access the private varibale in another class, i created instance of the class and tried to access it but couldn't. can someone point out what I did wrong in the code below?
using System;
namespace lab_first
{
public class AccessModifiers
{
private int Abc { get; set; }
private int bcd { get; set; }
}
class Program
{
static void Main(string[] args)
{
var acc = new AccessModifiers();
Console.WriteLine(acc.Abc)
}
}
}

You make members private so that nobody outside the class can access them.
This goes inline with the principle of information hiding.
Your example should look like this:
public class AccessModifiers
{
// You can only access this inside of the class AccessModifiers
private int Abc { get; set; }
internal void SetValue(int x){
// Access possible, because SetValue() is inside the same class
Abc = x;
}
internal int GetValue(){
// Access possible, because GetValue() is inside the same class
return Abc;
}
}
class Program
{
static void Main(string[] args)
{
var acc = new AccessModifiers();
// Abc is never modified directly, only indirectly.
acc.SetValue(5);
Console.WriteLine(acc.GetValue());
}
}
However, there is still a way to access the private member. It's called Reflection. However, note that private variables are considered an implementation detail and might change at any time, so you can't rely on it. E.g. someone might change the name from Abc to def and your Reflection-based approach fails.

You can either change private to internal or public in this case.
Another way is declaring the variables in the class as private and using C# Properties in the class to set and get the values of variables. this is called encapsulation which is a protective shield that prevents the data from being accessed by the code outside this shield).
public class AccessModifiers
{
private int _abc { get; set; }
private int _bcd { get; set; }
public int Abc
{
get
{
return _abc;
}
set
{
_abc = value;
}
}
public int Bcd
{
get
{
return _bcd;
}
set
{
_bcd = value;
}
}
}

I have a C# console project I am working on With agetter and no setter

Okay so I am working on a project that haves a abstract public abstract bool IsFull { get; } this is how the school wants me to set it up. I was trying to figure out a work around that but I can't. I have a few files not sure if I want them all to post. so in my class it is inherited from a different class. so when I initiate it from the program cs class I can't get the boolean to change with a simple IsFull = true. I tried IsFull.Equal(true); but read that just a comparison attribute. I will show my code. Remember this is 100% new to me so if you asked questions why don't i do it this way the answer is I never was taught that lol.
So is there a way I can override it within the sweettooth class?
My Ninja class
using System.Collections.Generic;
using IronNinja.Interfaces;
namespace IronNinja.Models
{
abstract class Ninja
{
protected int calorieIntake;
public List<IConsumable> ConsumptionHistory;
public Ninja()
{
calorieIntake = 0;
ConsumptionHistory = new List<IConsumable>();
}
public abstract bool IsFull { get; }
public abstract void Consume(IConsumable item);
}
}
my inherited class sweettooth
using IronNinja.Interfaces;
namespace IronNinja.Models
{
class SweetTooth : Ninja
{
public string Name;
public SweetTooth(string name)
{
Name = name;
}
public override bool IsFull { get; }
public override void Consume(IConsumable item)
{
// provide override for Consume
int sweet = 0;
if (calorieIntake >= 1500)
{
}
else
{
if (item.IsSweet)
{
sweet = 10;
}
ConsumptionHistory.Add(item);
calorieIntake += item.Calories + sweet;
}
item.GetInfo();
}
}
}
Lastly my Programs .cs file
using System;
using IronNinja.Models;
namespace IronNinja
{
class Program
{
static void Main(string[] args)
{
Buffet hungryJack = new Buffet();
SweetTooth Albert = new SweetTooth("Alby");
while (!Albert.IsFull)
{
Albert.Consume(hungryJack.Serve());
}
foreach (Food item in Albert.ConsumptionHistory)
{
Console.WriteLine(item.Name);
System.Console.WriteLine(item.GetInfo());
}
}
}
}

From my understanding, the IsFull property can simply provide the logic to return whether or not the SweetTooth is full:
public override bool IsFull => calorieIntake >= 1500;
And then in SweetTooth.Consume you would check if they are full before consuming more consumables:
public override void Consume(IConsumable item)
{
// provide override for Consume
int sweet = 0;
if (IsFull)
{
return;
}
else
{
if (item.IsSweet)
{
sweet = 10;
}
ConsumptionHistory.Add(item);
calorieIntake += item.Calories + sweet;
}
item.GetInfo();
}

You simply can't, by language design. You can't make your subclass "more permissive" than the parent class.
If you want to assign IsFull property, you have to do it into the SweetTooth class through the constructor. Generally if you set a property with private setter is because you want to manage its state internally and do not let the client code to handle it.
Then, change the SweetTooth constructor as per below:
public SweetTooth(string name, bool isFull)
{
Name = name;
IsFull = isFull;
}
The alternative is to add a private backing field, but again you can edit this only internally:
private bool _isFull;
public override bool IsFull => _isFull;
The Equal method compares two values. In your specific case you called bool.Equals(bool) overload which worked as Albert.IsFull == true

string created from variable in c#

Is it possible to to define a string from a variable where the string does NOT have quotations. Example:
public class aclass
{
public string athing;
}
public void example(string thing)
{
aclass thing = new aclass();
}
The string thing can't be put into aclass thing = new aclass(); normaly.
Is there anyway to do it?

You need a constructor
void Main()
{
CreateExampleObject("testing");
}
public class Example
{
// This is a constructor that requires a string as an argument
public Example(string text)
{
this.Text = text;
}
public string Text { get; set; }
}
public void CreateExampleObject(string text)
{
Example example = new Example(text);
Console.WriteLine(example.Text);
}

You can do it this using many way but generally standard way is using constructor
please refer this link for better understanding.
C# : assign data to properties via constructor vs. instantiating

You have to ways of setting fields/property value of an object.
First is to do it through the constructor, as mentioned in other answer.
Second can be implmeneted in various ways:
Expose public property making field privte:
public class aclass
{
private string _athing;
public string Athing
{
get { return _athing; }
set { _athing = value; }
}
}
public void example(string thing)
{
aclass aclass = new aclass();
aclass.Athing = thing;
}
Or even shorter, you could use property:
public class aclass
{
public string Athing {get; set; }
}
Using your implementation, you make your field public, so you can set it easily:
public void example(string thing)
{
aclass aclass = new aclass();
aclass.athing = thing;
}
But it doesn't comply with OOP encapsulation principle.

C# Calling variables from other classes

this is probably very simple, but I have always just made one big class and never tried make clean code. Now I am trying and experiencing errors..
So, this is the idea:
class1
{
method1 { value 1; value 2 }
method2 { value 3; value 4 }
method3 { uses method4 from class2 }
}
class2
{
method4 { uses values 1-4 from class1 }
}
I am doing it by calling: class1 c1 = new class1() in method4 and class2 c2 = new class2 in method3.
So this is what happens:
method1, method2 produce values 1-4
method3 calls class2 c2 = new class2
I get into class2, then into method4 and get null/0 values instead of what I made in first step.

Instead of creating a new instance of class1 in method4 you should pass the current class1 instance (accessible through this inside method3) as a parameter to this method to get the same result.

You need to be more specific...
class Class1
{
Class2 _class2;
public Class1(Class2 class2)
{
_class2 = class2;
}
public void method3()
{
//call _class2.method4()
}
}
class Class2
{
Class1 _class1;
public Class2(Class1 class1)
{
_class1 = class1;
}
public void Method4()
{
//call _class1.MethodWhatever()
}
}

So when you need to access variables within a class you can obviously do this simply via the 'public' modifier, however the below example is not best practice but we will get onto that shortly...
public class MyTestClass
{
public int MyAge;
}
This is a field - fields should really be private, and we should use a property to expose the field. However if you did do this, then you can access that like so:
var foo = new MyTestClass();
var hisAge = foo.MyAge;
Of course based on your requirements maybe you don't want the user to access the variable directly, but rather get a value after some computation has been done on other variables.
You can do this like so:
public class MyTestClass
{
private int _gamesPlayed;
private int _gamesLost;
public int NumberOfWins { get { return _gamesPlayed - _gamesLost; } }
}
NumberOfWins is a Property. It computes the values of two of our fields and reutrns it. See how we have the private modifier, these can't been seen outside of the scope of that class. NumberOfWins can be accessed the same way as MyAge in the previous example.
To be honest, it sounds like you are rather using pseudo-code or are a beginner.
I recommend checking out the following articles for a bit more information on what I have stated.
Modifiers - C# Reference
Properties C# Programming Guide
Difference between a Field and a Property in C#

it is really unclear what you want to achieve and how class1 is linked to class2. If your class2 is ONLY useful for the first class then (and only then) you could use nested classes...
class OuterClass {
string value1;
string value2;
string value3;
// ...
class InnerClass
{
OuterClass o_;
public InnerClass(OuterClass o)
{
o_ = o;
}
public string GetOuterString()
{
return o_.value1 + o.value2 + o.value3; //...
}
}
void SomeFunction()
{
InnerClass i = new InnerClass(this);
i.GetOuterString();
}
}
This would create a clear binding from the inner class (class 2) to the outer one. It is not easier though.
Edit: OK, after your edit I see a whole different story..

Well, here is some code for you. I'm not sure it it's what you require. It might help you get started, though. You can try running it here: https://dotnetfiddle.net/#
This is Class1. It exposes some of its data via properties.
public class Class1
{
// these are properties
public int Value1 { get; set; }
public int Value2 { get; set; }
public int Value3 { get; set; }
public int Value4 { get; set; }
public void Method1()
{
Value1 = 1;
Value2 = 2;
}
public void Method2()
{
Value3 = 3;
Value4 = 4;
}
public void Method3()
{
// uses method4 from class2
var c = new Class2();
c.Method4();
}
}
This is Class2. It calls methods from Class1 and accesses its properties.
public class Class2
{
public void Method4()
{
//uses values 1-4 from class1
var c = new Class1();
c.Method1();
c.Method2();
Console.WriteLine(c.Value1);
Console.WriteLine(c.Value2);
Console.WriteLine(c.Value3);
Console.WriteLine(c.Value4);
}
}
This uses both closes and shows the result:
using System;
public class Program
{
public static void Main()
{
var c1 = new Class1();
c1.Method3();
}
}

Reaching public property of parent class

a simple question :
public class class1
{
public string string1;
public class class2
{
public string string2
{
get{ string tmp = class1.string1; }
}
}
}
I want to be able to reach class1.string1 from class2.string2.get, but I cant. What would you recommend me to change, so that I can do that?
Thanx

Passing class1 reference to class2 in constructor:
public class class1 {
public string string1;
public class class2 {
private class1 _Reference;
public class2(class1 reference) {
if (reference == null) {
throw new ArgumentNullException("reference");
}
_Reference = reference;
}
public string string2 {
get { return _Reference.string1; }
}
}
}
Passing class1 reference to class2 after both classes have been created:
public class class1 {
public string string1;
public class class2 {
private class1 _Reference;
public class1 Reference {
set { _Reference = value; }
}
public string string2 {
get { return _Reference.string1; }
}
}
}
static void usage() {
var foo = new class1();
var bar = new class1.class2();
bar.Reference = foo;
string value = bar.string2;
}

There is no means of accessing a class from within a nested class that I know of. Class nesting doesn't lead to automatic instantiation of the surrounding class, it's just a (usually rather smelly) means of structuring your code.
You would either need a reference to an actual instance of Class1 inside Class2 or you'd need a static method on Class1.
Another way to accomplish this would be to use inheritance, but that's a whole different beast to tame:
public class Class1 {
protected String String1 { get; set; }
}
public class Class2 : Class1 {
public String String2 {
get {
String PropertyFromClass1 = base.String1;
// ...
}
}
}
That said: Your code wouldn't compile, string2's getter doesn't return anything. And please make yourself familiar with C#'s naming conventions.

Thanx for the suggestions. Due to the specific nature of the code, I had to solve this situation with a global public static class in another namespace.

Coming from Java I faced this "problem" when I started developing in C#.
As clearly explained by Dennis Traub and in this article in C# you can't access outer class members or methods. So you have to implement what in Java happens automatically:
class OuterClass {
string s;
// ...
class InnerClass {
OuterClass o_;
public InnerClass(OuterClass o) { o_ = o; }
public string GetOuterString() { return o_.s; }
}
void SomeFunction() {
InnerClass i = new InnerClass(this);
i.GetOuterString();
}
}