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C# count and list pairs of dict of another method

I have the below code, and I need to find how many, and all pairs, of dictionary, which however belongs in another namespace's method:
using sys = System;
using gen = System.Collections.Generic;
namespace xtra
{
class TestClass
{
public void Sing()
{
gen::Dictionary<string, int> dict = new gen::Dictionary<string, int>()
{
["A"] = 1,
["B"] = 2,
["C"] = 3
};
}
}
}
namespace ConsoleApp99
{
class Program
{
static void Main(string[] args)
{
xtra.TestClass Joe = new xtra.TestClass();
Joe.Sing();
foreach (string name in Joe.Keys) //error!
sys.Console.WriteLine($"{name} {dict[name]}"); //error!
}
}
}
So, the method Sing creates and populates a dictionary, but, upon instantiation in another namespace (in Main), I can create it, but, how do I count pairs and print their values?? I do understand that Joe is a method that makes the dictionary, but I have no clue to reference Joe's dictionary..

The dict property access modifier must be public in order to access him from another class.
Another approach is to expose only the dict property by encapsulating him and make Sing() method private.
class TestClass
{
private Dictionary<string, int> _dict;
public Dictionary<string, int> dict
{
get
{
if (_dict == null)
{
Sing();
}
return _dict;
}
set { _dict = value; }
}
private void Sing()
{
_dict = new Dictionary<string, int>()
{
["A"] = 1,
["B"] = 2,
["C"] = 3
};
}
}
class Program
{
static void Main(string[] args)
{
xtra.TestClass Joe = new xtra.TestClass();
foreach (string name in Joe.dict.Keys)
sys.Console.WriteLine($"{name} {Joe.dict[name]}");
Console.ReadLine();
}
}

You need to define this dictionary as public property inside of TestClass in order to have access to it from different class/namespace:
namespace xtra
{
class TestClass
{
public Dictionary<string, int> Dict { get; set; }
public void Sing()
{
Dict = new Dictionary<string, int>()
{
["A"] = 1,
["B"] = 2,
["C"] = 3
};
}
}
}
namespace ConsoleApp99
{
class Program
{
static void Main(string[] args)
{
xtra.TestClass Joe = new xtra.TestClass();
Joe.Sing();
foreach (string name in Joe.Dict.Keys) //error!
sys.Console.WriteLine($"{name} {Joe.Dict[name]}"); //error!
}
}
}

Writing into nested Dictionary in Unity3D

Can I not write values into my nested dictionary directly?
It would be nice if I could access it like this:
public Dictionary<string, Dictionary<string, Dictionary<string, int>>> planets =
new Dictionary<string, Dictionary<string, Dictionary<string, int>>>();
planets[Planet.CharacterId]["MetalMine"]["Level"] = 0;
But I'm getting:
KeyNotFoundException: The given key was not present in the dictionary.
Does this mean I got to insert my Keys after each other?

Does this mean I got to insert my Keys after each other?
Yes, you need to initialize each in order:
planets[Planet.CharacterId] = new Dictionary<string, Dictionary<string, int>>();
planets[Planet.CharacterId]["MetalMine"] = new Dictionary<string, int>();
planets[Planet.CharacterId]["MetalMine"]["Level"] = 0;
You could use collection initializer syntax here, but that won't make stuff much more readable nor maintainable.
Instead of a dictionary of dicionaries of dictionaries you seem to be better off using a class:
public class Planet
{
public List<Mine> Mines { get; set; }
}
public class Mine
{
public string Type { get; set; }
public int Level { get; set; }
}
var planets = new Dictionary<string, Planet>();
planets[Planet.CharacterId] = new Planet
{
Mines = new List<Mine>
{
new Mine
{
Type = "Metal",
Level = 0
}
};
}

It's may be helpful or Nested dictionary alternative.
Create Sample.cs script and test it.
public Dictionary<string,Tuple<string,string,string,int>> _planets = new Dictionary<string, Tuple<string,string, string, int>>();
void Start()
{
string myKey = string.Concat("1","MetalMine","Level");
if(!_planets.ContainsKey(myKey))
{
_planets.Add(myKey,Tuple.Create("1","MetalMine","Level",0));
}
Debug.Log("_planets mykey "+myKey+" ==> "+_planets[myKey].Item4);
}

In a Dictionary TryGetValue, how do I write the out parameter (and get it's values) if it's part of a class?

Past question thread and link to fullpast code HERE
I create my dictionary with a class for a parameter so it can hold two string values. Now I'm trying to write a TryGetValue to out both of the strings in this class:
public class DictionaryInitializer
{
public class DictionarySetup
{
public string theDescription { get; set; }
public string theClass { get; set; }
}
As you can see, there's theDescription and theClass nested in the DictionarySetup. Then I would create the dictionaries using that class here:
public class DictionaryInit
{
//IS_Revenues data
public Dictionary<int, DictionarySetup> accountRevenue = new Dictionary<int, DictionarySetup>()
{
{ 400000, new DictionarySetup {theDescription="Call", theClass="Revenues"}}
};
public Dictionary<int, DictionarySetup> accountExpenses = new Dictionary<int, DictionarySetup>()
{
{790100, new DictionarySetup { theDescription="Currency Hedge", theClass="Other income/expense"}}
};
}
Then, my extension method where I plan to use my TryGetValue on the dictionary:
public void DictionaryUseKey(int MapCode, int MapKey, int rowindex, Dictionary<int, DictionarySetup> AccountLexicon)
{
AccountLexicon[1] = new DictionarySetup();
DictionarySetup Classes;
DictionarySetup Descriptions;
//Saw the above code in another thread, not sure if it's what I should be doing but it seems pretty close to what I want, however, I don't know how to specify the DictionarySetup.theDescription for example;
AccountLexicon.TryGetValue(MapKey, out Classes);
{
//I want to be able to write theDescription and theClass into string variables for use below if the `TryGetValue` returns true, but it seems to me that it can only out one value? How does this work?
DGVMain.Rows[rowindex].Cells[3].Value = ?? how do I write something like... theValues.theDescription;
DGVMain.Rows[rowindex].Cells[11].Value = ?? how do I write something like... theValues.theClass;
}
}
Lastly, I call the extension method in my event like so:
private void btnMapper_Click(object sender, EventArgs e)
{
for (int rowindex = 0; rowindex < DGVMain.RowCount; rowindex++)
{
int accountKey = Convert.ToInt32(DGVMain.Rows[rowindex].Cells[2].Value);
int projCode = Math.Abs(Convert.ToInt32(DGVMain.Rows[rowindex].Cells[7].Value));
int deptCode = Math.Abs(Convert.ToInt32(DGVMain.Rows[rowindex].Cells[9].Value));
int AbsoluteKey = Math.Abs(accountKey);
while (AbsoluteKey >= 10) { AbsoluteKey /= 10; }
while (deptCode >= 10) { deptCode /= 10; }
theDictionary = new DictionaryInit();
DictionaryUseKey(deptCode, accountKey, theDictionary.accountRevenue);
}
}

Actually the TryGetValue method will returns a boolean value represents the presence of the specified key, if the key is found, the corresponding value will be stored in the out parameter. Here in your case the out parameter is Classes and are defined in your code like this: DictionarySetup Classes. which means in case the key is present in the Dictionary means corresponding DictionarySetup object will be stored in the Classes so you can access the theDescription and theClass from Classes; Consider the code below:
if(AccountLexicon.TryGetValue(MapKey, out Classes))
{
DGVMain.Rows[rowindex].Cells[3].Value = Classes.theDescription;
DGVMain.Rows[rowindex].Cells[11].Value = Classes.theClass;
}

Cannot update a single item (object) in a List C#

I have a list of objects:
List<NPortfolio> Portfolios = new List<NPortfolio>();
Portfolios.Add(new NPortfolio(1, "1", emptyPositions));
Portfolios.Add(new NPortfolio(2, "2", emptyPositions));
Now i want to call a Method on the object that modifies its properties:
Portfolios[0].UpdatePositions(db.GetPortfolio(1, Today));
The method is this:
public void UpdatePositions(Dictionary<string, double> valuepairs)
{
foreach (var k in this.positions.Keys.ToList())
{
if (valuepairs.ContainsKey(k))
this.positions[k] = valuepairs[k];
}
}
This works, but the problem is that when I try to update just the first item of the list:
Portfolios[0].UpdatePositions(db.GetPortfolio(1, Today));
ALL ITEMS OF THE LIST ARE UPDATED!!!
I cannot find why all items are updated and not only item 0.
Please help this is really an headache
many thanks
class definition:
public class NPortfolio
{
public string p_id { get; set; }
public int p_nr { get; set; }
private Dictionary<string, double> positions;
public NPortfolio(int nr, string id, Dictionary<string, double> pos)
{
p_nr = nr;
p_id = id;
positions = pos;
}
public void UpdatePositions(Dictionary<string, double> valuepairs)
{
foreach (var k in this.positions.Keys.ToList())
{
if (valuepairs.ContainsKey(k))
this.positions[k] = valuepairs[k];
}
}
public Dictionary<string, double> getPositions()
{
return positions;
}
}

The problem is from this
Portfolios.Add(new NPortfolio(1, "1", emptyPositions));
Portfolios.Add(new NPortfolio(2, "2", emptyPositions));
You are passing the same dictionary to both classes, so if you modify one of the classes you modify both instances.
You must create a new dictionary inside the constructor of NPortfolio so each class has a unique copy.
public NPortfolio(int nr, string id, Dictionary<string, double> pos)
{
p_nr = nr;
p_id = id;
positions = new Dictionary<string, double>(pos);
}
This will make a shallow copy of the dictionary and should solve your issue for now.

You're passing the same dictionary into your objects. So when you update it in one you end up seeing the changes in the other. You should create a new dictionary inside your constructor and populate it with the values passed in.
public NPortfolio(int nr, string id, Dictionary<string, double> pos)
{
p_nr = nr;
p_id = id;
positions = new Dictionary<string, double>(pos);
}

.NET Dictionary as a Property

Can someone point me out to some C# code examples or provide some code, where a Dictionary has been used as a property for a Class.
The examples I have seen so far don't cover all the aspects viz how to declare the dictionary as property, add, remove, and retrieve the elements from the dictionary.

Here's a quick example
class Example {
private Dictionary<int,string> _map;
public Dictionary<int,string> Map { get { return _map; } }
public Example() { _map = new Dictionary<int,string>(); }
}
Some use cases
var e = new Example();
e.Map[42] = "The Answer";

sample code:
public class MyClass
{
public MyClass()
{
TheDictionary = new Dictionary<int, string>();
}
// private setter so no-one can change the dictionary itself
// so create it in the constructor
public IDictionary<int, string> TheDictionary { get; private set; }
}
sample usage:
MyClass mc = new MyClass();
mc.TheDictionary.Add(1, "one");
mc.TheDictionary.Add(2, "two");
mc.TheDictionary.Add(3, "three");
Console.WriteLine(mc.TheDictionary[2]);
EDIT
When you use C# version 6 or later, you can also use this:
public class MyClass
{
// you don't need a constructor for this feature
// no (public) setter so no-one can change the dictionary itself
// it is set when creating a new instance of MyClass
public IDictionary<int, string> TheDictionary { get; } = new Dictionary<int, string>();
}

You could also look into indexers. (official MSDN documentation here)
class MyClass
{
private Dictionary<string, string> data = new Dictionary<string, string>();
public MyClass()
{
data.Add("Turing, Alan", "Alan Mathison Turing, OBE, FRS (pronounced /ˈtjʊ(ə)rɪŋ/) (23 June, 1912 – 7 June, 1954) was a British mathematician, logician, cryptanalyst and computer scientist.")
//Courtesy of [Wikipedia][3]. Used without permission
}
public string this [string index]
{
get
{
return data[index];
}
}
}
Then, once you have populated the dictionary internally, you can access it's information by going
MyClass myExample = new MyClass();
string turingBio = myExample["Turing, Alan"];
EDIT
Obviously, this has to be used carefully, because MyClass is NOT a dictionary, and you cannot use any dictionary methods on it unless you implement them for the wrapper class. But indexers are a great tool in certain situations.

In order to ensure the encapsulation is correct and the dictionary cannot be updated outside the class using Add or the form ExampleDictionary[1]= "test", use IReadOnlyDictionary.
public class Example
{
private Dictionary<int, string> exampleDictionary;
public Example()
{
exampleDictionary = new Dictionary<int, string>();
}
public IReadOnlyDictionary<int, string> ExampleDictionary
{
get { return (IReadOnlyDictionary<int, string>)exampleDictionary; }
}
}
The following code will not work, which is not the case if IDictionary is used:
var example = new Example();
example.ExampleDictionary[1] = test;

Another example of using a dictionary as a static property with only the get accessor:
private static Dictionary <string, string> dict = new Dictionary <string,string>(){
{"Design Matrix", "Design Case"},
{"N/A", "Other"}
};
public static Dictionary <string, string> Dict
{
get { return dict}
}
This structure can be used to replace values.

An example...
public class Example
{
public Dictionary<Int32, String> DictionaryProperty
{
get; set;
}
public Example()
{
DictionaryProperty = new Dictionary<int, string>();
}
}
public class MainForm
{
public MainForm()
{
Example e = new Example();
e.DictionaryProperty.Add(1, "Hello");
e.DictionaryProperty.Remove(1);
}
}

Since .net 4.6 you can also define a Dictionary like this:
private Dictionary<string,int> Values => new Dictionary<string, int>()
{
{ "Value_1", 1},
{ "Value_2", 2},
{ "Value_3", 3},
};
It's called Expression-bodied members!

You mean like a property bag ?
http://www.codeproject.com/KB/recipes/propertybag.aspx