how to read a value in my Dictionary

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Hi Guy, please i Need your help. i learn today how to set value in my Dictionary but i don't really know how to get the different Value of them.

I insert data in a form of list and send it later in my database. the Problem is that i don't know how to get all this data out of my List. I read that it is possible with LinQ but i don't know. Please has somebody an idea? Hier is my Code.

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;
using System.Linq;

namespace Kommissionierung
{
    public class AuswahlListe
    {  
        Dictionary<string, Dictionary<string, string>> ChoiceList = new Dictionary<string, Dictionary<string, string>>();

        public void ChoiceAdd(Choice choice)
        {

            if (ChoiceList.ContainsKey(choice.MaterialsNummer))
            {       
                ChoiceList[choice.MaterialsNummer].Add(choice.CommandsNummer, choice.PersonalNr);
            }
            else
            {
                Dictionary<string, string> newinner = new Dictionary<string, string>();
                newinner.Add(choice.CommandsNummer, choice.PersonalNr);
                ChoiceList.Add(choice.MaterialsNummer, newinner);
            }

        }

        public void ChoiceListRemove(Choice choice)
        {
            if (ChoiceList.ContainsKey(choice.MaterialsNummer))
            {
                ChoiceList[choice.MaterialsNummer].Remove(choice.CommandsNummer);
            }
        }
        
    }
}

please Help me

Posted 21-Jul-13 10:25am

stefan from germany

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Comments

[no name] 21-Jul-13 16:40pm

You should start by reading the documentation, http://msdn.microsoft.com/en-us/library/bb347013.aspx

stefan from germany 21-Jul-13 17:07pm

if i ask you it is because i don't understand how to make t. the Problem is not only to read but to understand. I read it but until yet it is not clear.

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Sergey Alexandrovich Kryukov · Accepted Answer · 2013-07-21T11:15:00

The idea of the dictionary is to take some value by some unique key, with time complexity of O(1), using the mechanism based on hash table.
Please see:
http://en.wikipedia.org/wiki/Hash_table[^],
http://en.wikipedia.org/wiki/Big_O_notation[^],
http://en.wikipedia.org/wiki/Time_complexity[^].

You created a nested dictionary, which allows you to find a dictionary by a string key, and then a value in that dictionary through yet another key. For example:

C#

string FindByKeys(string dictionaryKey, string key) {
    try {
         return (ChoiceList[dictionaryKey])[key];
    } catch (KeyNotFoundException) {
         return null;
    } //exception
} //FindByKeys

I would say, the name ChoiceList is very confusing. This is not a list, this is a dictionary, a fundamentally different collection.

—SA