// http://svc.luckstar.com.tw/CodeHelper/cs/index.html
// 2017-03-26, honda@luckstar.com.tw, Create.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
// add
using System.Collections.Specialized;
using System.Collections;

namespace ConsoleBase
{
    public class COrderedDictionary
    {
        OrderedDictionary mList1 = new OrderedDictionary();
        public void Run()
        {
            Console.WriteLine("Basic of OrderedDictionary:");

            // Creates and initializes a OrderedDictionary.
            mList1.Add("testKey1", "testValue1");
            mList1.Add("testKey2", "testValue2");
            mList1.Add("keyToDelete", "valueToDelete");
            mList1.Add("testKey3", "testValue3");

            ICollection keyCollection = mList1.Keys;
            ICollection valueCollection = mList1.Values;

            // Display the contents using the key and value collections
            DisplayContents(keyCollection, valueCollection, mList1.Count);

            // Modifying the OrderedDictionary
            if (!mList1.IsReadOnly)
            {
                // Insert a new key to the beginning of the OrderedDictionary
                mList1.Insert(0, "insertedKey1", "insertedValue1");

                // Modify the value of the entry with the key "testKey2"
                mList1["testKey2"] = "modifiedValue";

                // Remove the last entry from the OrderedDictionary: "testKey3"
                mList1.RemoveAt(mList1.Count - 1);

                // Remove the "keyToDelete" entry, if it exists
                if (mList1.Contains("keyToDelete"))
                {
                    mList1.Remove("keyToDelete");
                }
            }

            Console.WriteLine("{0}Displaying the entries of a modified OrderedDictionary.", Environment.NewLine);
            DisplayContents(keyCollection, valueCollection, mList1.Count);

            // Clear the OrderedDictionary and add new values
            mList1.Clear();
            mList1.Add("newKey1", "newValue1");
            mList1.Add("newKey2", "newValue2");
            mList1.Add("newKey3", "newValue3");

            // Display the contents of the "new" Dictionary using an enumerator
            IDictionaryEnumerator myEnumerator = mList1.GetEnumerator();

            Console.WriteLine("{0}Displaying the entries of a \"new\" OrderedDictionary.",
                Environment.NewLine);

            DisplayEnumerator(myEnumerator);
        }

        // Displays the contents of the OrderedDictionary from its keys and values
        public static void DisplayContents(ICollection listKey, ICollection listValue, int iSize)
        {
            String[] myKeys = new String[iSize];
            String[] myValues = new String[iSize];
            listKey.CopyTo(myKeys, 0);
            listValue.CopyTo(myValues, 0);

            // Displays the contents of the OrderedDictionary
            Console.WriteLine(" INDEX KEY VALUE");
            for (int i = 0; i < iSize; i++)
            {
                Console.WriteLine(" {0,-5} {1,-25} {2}", i, myKeys[i], myValues[i]);
            }
            Console.WriteLine();
        }
        // Displays the contents of the OrderedDictionary using its enumerator
        public static void DisplayEnumerator(IDictionaryEnumerator enumerator1)
        {
            Console.WriteLine(" KEY VALUE");
            while (enumerator1.MoveNext())
            {
                Console.WriteLine(" {0,-25} {1}", enumerator1.Key, enumerator1.Value);
            }
        }
    }
}


result:

Basic of OrderedDictionary:
 INDEX KEY VALUE
 0     testKey1                  testValue1
 1     testKey2                  testValue2
 2     keyToDelete               valueToDelete
 3     testKey3                  testValue3


Displaying the entries of a modified OrderedDictionary.
 INDEX KEY VALUE
 0     insertedKey1              insertedValue1
 1     testKey1                  testValue1
 2     testKey2                  modifiedValue


Displaying the entries of a "new" OrderedDictionary.
 KEY VALUE
 newKey1                   newValue1
 newKey2                   newValue2
 newKey3                   newValue3