multi values in Hashtable (c#)

Question

2.67/5 (3 votes)

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How can I make a hashTable with three parameters? I want to store phone numbers, names and addresses using a hashTable. Phone number as the key, and the name, address as its value. But I can put two data only, phone number and name. How do I get to save a phone number, name, address in the hashTable?

C#

Hashtable phoneBook;

public FrmPhoneBook()
{
    InitializeComponent();
    phoneBook = new Hashtable();
}

public void addNewPhoneBook(string name, string tel, string add)
{
    string names = name;
    string telp = tel;
    string address = add;

    if (!phoneBook.ContainsKey(telp))
    {
        phoneBook.Add(telp, names);
        getDetails();
    }
}

public void getDetails()
{
    lvDetails.Items.Clear();
    foreach (DictionaryEntry values in phoneBook)
    {
        lvDetails.Items.Add(values.Value.ToString());
        lvDetails.Items[lvDetails.Items.Count - 1].SubItems.Add(
           values.Key.ToString());  
    }
}

Posted 3-Dec-11 18:26pm

upup7

Add a Solution

4 solutions

Solution 3

C#

This is what I would do:
Create a new class: Contact, with three properties: Phone, Name, Address, and the rest of the code would be something like :

C#

public void addNewPhoneBook(string name, string tel, string add)
{
    var contact = new Contact(name, tel, add); 
    if (!phoneBook.ContainsKey(tel))
    {
        phoneBook.Add(tel, contact);
        getDetails();
    }
}

for getDetails ...

C#

public void getDetails()
{
    lvDetails.Items.Clear();
    lvDetails.Items = phoneBook.Values;
}

I did not compile this code but I think it must work.
It is better to have a Dictionary instead of a Hashtable, your dictionary could be defined as

C#

Dictionary<string, phoneBook> = new Dictionary<string, phoneBook>();

Posted 5-Dec-11 4:24am

emardini

Updated 5-Dec-11 9:00am

v2

Solution 4

//This code is Tested Code For Hash Table

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Collections;

namespace HashTableDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        // Create a new hash table.
        //
        Hashtable openWith = new Hashtable();
        private void btnAdd_Click(object sender, EventArgs e)
        {
            string Hashkey = txtHashKey.Text;
            string HashVal = txtHashVal.Text;

            List<string> details = new List<string>();
            
            if (!openWith.ContainsKey(Hashkey))
            {
                details.Add(HashVal );
                openWith.Add(Hashkey, details);
            }
            else
            {
                foreach (DictionaryEntry values in openWith)
                {
                    string keyVal = Convert.ToString(values.Key);
                    if (keyVal == Hashkey)
                    {
                        List<string> addInHashValues = (List<string>)values.Value;
                        addInHashValues.Add(HashVal);
                    }
                }
            }
            rtbHash.Text = "";           
            getDetails();
        }

        public void getDetails()
        {
            foreach (DictionaryEntry values in openWith)
            {
                string keyVal = Convert.ToString(values.Key);
                rtbHash.Text += keyVal;
                List<string> details = (List<string>)values.Value;
                foreach (string testVal in details)
                {
                    rtbHash.Text += " "+ testVal;
                }
                rtbHash.Text += "\n";        
            }
        }

        private void btnShow_Click(object sender, EventArgs e)
        {
            rtbHash.Text = ""; 
            getDetails();
        }
    }
}

Posted 9-Feb-12 0:41am

Harshal Chaudhari

Updated 9-Feb-12 0:42am

v2

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-12-03T18:50:00

First of all, instead of Hashtable, use one of generic classes from <codey>System.Collections.Generic: <code>Dictionary (I would say, this is a candidate #1), SortedDictionary or SortedList. All these types are indexed with the key and provide computational complexity O<1> for the search by index; the difference is mostly the trade-off between speed and memory overhead. Non-generic type are rendered obsolete (for new development; formally, they are not obsolete) by introduction of generics in .NET 2.0. Type cast required by non-generic containers is a really bad thing.

Now, the answer to the question is really simple: create a structure or a class with the members for address and name; use this class as a value type, and the telephone as the key type as you did before.

—SA

Eduard Lu · Accepted Answer · 2011-12-03T18:48:00

Solution 1

you can use a List of string instead of a single string value. Try the ff:

C#

List<string> details = new List<string>();
list.Add(tel);
list.Add(add); 
</string></string>

and then use name or tel as key

C#

HashTable obj = new HashTable();
obj.Add(name, details);
//or obj.Add(tel, details);

Please mark as answer and vote 5 if this solved your problem

Regards,
Eduard

Posted 3-Dec-11 18:48pm

Eduard Lu

Updated 3-Dec-11 18:55pm

v3

Comments

upup7 4-Dec-11 1:03am

then how to display in the listbox. when i want to display in the ListBox it's appear an error. for its key can appear, but for its value would not appear.

foreach (DictionaryEntry val in phoneBook)
{
listBox1.Items.Add("key :" + val.Keys + "and value : " + val.Values);
}

appear in the listbox like this:

key : 1 and value : System.Collections.Generic.List[System.String]

[no name] 4-Dec-11 1:11am

you need to create another iteration to break down the values of the List. for ex:
string values = string.Empty;
foreach(string val in details.Items)
{
values += val + ", ";
}

then after getting the values from list, remove the trailing ","

upup7 4-Dec-11 6:26am

then how if I want to edit one of its value. eg want to edit the name or address only. I've tried but its value changed all.

public void editValueName(string tel, string add)
{
string address = add;
string telp = tel;

if (phoneBook.ContainsKey(tel))
{
phoneBook[tel] = address;
getDetails();
}
}