Csharp/CSharp Tutorial/Data Structure/IDictionary

Creating a list from a dictionary

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, DateTime> dictionary = new Dictionary<string, DateTime>();
        List<KeyValuePair<string, DateTime>> keyValueList = new List<KeyValuePair<string, DateTime>>(dictionary);
    }
}

IDictionary<TKey,TValue>: Add some entries into the dictionary

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, decimal> salaryMap = new Dictionary<string, decimal>();
        salaryMap.Add("S", 60.5M);
        salaryMap.Add("W", 10.0M);
        salaryMap.Add("J", 30.99M);
    }
}

IDictionary<TKey,TValue>: Check whether certain keys exist in the map

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, decimal> salaryMap = new Dictionary<string, decimal>();
        salaryMap.Add("S", 60.5M);
        salaryMap.Add("W", 10.0M);
        salaryMap.Add("J", 30.99M);
        
        Console.WriteLine(salaryMap.ContainsKey("S")); 
        Console.WriteLine(salaryMap.ContainsKey("T"));
    }
}

True
False

IDictionary<TKey,TValue>: iterate over the map and add up the values

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, decimal> salaryMap = new Dictionary<string, decimal>();
        salaryMap.Add("S", 60.5M);
        salaryMap.Add("W", 10.0M);
        salaryMap.Add("J", 30.99M);
        decimal total = 0.0M;
        foreach (decimal d in salaryMap.Values)
            total += d;
        Console.WriteLine("{0:C}", total);
        
    }
}

$101.49

IDictionary<TKey,TValue>: Iterating over map/value pairs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, decimal> salaryMap = new Dictionary<string, decimal>();
        salaryMap.Add("S", 60.5M);
        salaryMap.Add("W", 10.0M);
        salaryMap.Add("J", 30.99M);
        foreach (KeyValuePair<string, decimal> kvp in salaryMap)
            Console.WriteLine("{0} == {1}", kvp.Key, kvp.Value);
    }
}

S == 60.5
W == 10.0
J == 30.99

IDictionary<TKey,TValue>: remove one entry

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, decimal> salaryMap = new Dictionary<string, decimal>();
        salaryMap.Add("S", 60.5M);
        salaryMap.Add("W", 10.0M);
        salaryMap.Add("J", 30.99M);
        
        salaryMap.Remove("W");
    }
}

IDictionary<TKey,TValue>: Retrieve some values from the map

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        IDictionary<string, decimal> salaryMap = new Dictionary<string, decimal>();
        salaryMap.Add("S", 60.5M);
        salaryMap.Add("W", 10.0M);
        salaryMap.Add("J", 30.99M);
        
        Console.WriteLine("{0:C}", salaryMap["S"]); 
        Console.WriteLine("{0:C}", salaryMap["J"]);
    }
}

$60.50
$30.99