C# .NET Writing To The Registry

In this article we can edit the registry to block a outlook configured email using c#.net.

A checklistbox is required to display all the configured email of the outlook, through which we can select the email id to be blocked:
All the email id are displayed by readsing from registry.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using Microsoft.Win32;
using System.Collections;

namespace ResumeParse
{
    public partial class Block : Form
    {
       
        ArrayList l1 = new ArrayList();
        ArrayList l2 = new ArrayList();
        ArrayList l3 = new ArrayList();
        //string j;
        Byte[] y;
        char[] c2;
        public static int ii = 0;
        DataSet ds = new DataSet();
        public Block()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // Add All Emial ID's;

            RegistryKey reg = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Windows messaging Subsystem\\Profiles\\Outlook", true);

            string[] d = reg.GetSubKeyNames();
            int uu = 0;
            foreach (object obj in d)
            {

                uu++;

                l1.Add(obj);

            }

            foreach (object o1 in l1)
            {

                string s2 = "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Windows messaging Subsystem\\Profiles\\Outlook\\" + o1.ToString();

                RegistryKey reg2 = Registry.CurrentUser.OpenSubKey(s2, true);
                string[] d1 = reg2.GetSubKeyNames();
                if (reg2.ValueCount > 0)
                {
                    char[] c1 = new char[1000];
                    foreach (object obj in d1)
                    {
                        string s3 = s2 + "\\"+obj.ToString();

                        RegistryKey rege = Registry.CurrentUser.OpenSubKey(s3, true);
                        if (rege.ValueCount > 0)
                        {
                            y = (Byte[])rege.GetValue("email");
                            // c1.Length = y.Length;
                            if (y != null)
                            {
                                foreach (byte b in y)
                                {
                                    c1[ii] = (char)b;
                                    ii++;
                                }
                                ii = 0;
                                c2 = new char[1000];
                                int k = 0;
                                for (int i = 0; i < c1.Length; i = i + 2)
                                {
                                    c2[k] = c1[i];
                                    k++;
                                }

                                string snr = new string(c2);
                                string a = snr.Replace("\0", "");
                               // string a = c2.ToString();

                                checkedListBox1.Items.Add(a);

                            }
                        }
                    }

                }

            }

           
        
            ds.ReadXml(@"D:\ResumeSettings\Email.xml");
            if (ds.Tables[0].Rows.Count > 0)
            {
                int x = checkedListBox1.Items.Count;
                DataRow[] dr = ds.Tables[0].Select("status like '1'");
                for (int di = 0; di < dr.Length; di++)
                {

                    string email = dr[di].ItemArray.GetValue(0).ToString();
                    for (int i = 0; i < x; i++)
                    {
                        if (email.ToLower().ToString().Equals(checkedListBox1.Items[i].ToString().ToLower().TrimStart().TrimEnd()))
                        {

                            int xx = checkedListBox1.Items.IndexOf(email.ToString());
                            checkedListBox1.SetItemChecked(xx, true);

                        }

                    }

                }
            }

            ds.Clear();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            CheckedListBox.CheckedItemCollection col = checkedListBox1.CheckedItems;
            string str = "";
            for (int i = 0; i < col.Count; i++)
            {
                str = str + " "+ col[i].ToString()+" ";
            }
         
            ds.ReadXml(@"D:\ResumeSettings\Email.xml");

            if (ds.Tables[0].Rows.Count > 0)
            {
                CheckedListBox.CheckedItemCollection chkitem = checkedListBox1.CheckedItems;
                int x = chkitem.Count;
                DataRow[] dr = ds.Tables[0].Select("status like '1'");
               
            
               
                for (int d = 0; d < dr.Length; d++)
                {
                       ds.Tables[0].Rows.Remove(dr[d]);
                }
            }

            ds.WriteXml(@"D:\ResumeSettings\Email.xml");
           
            ds.Clear();  
           
            ds.ReadXml(@"D:\ResumeSettings\Email.xml");
          
            for (int i = 0; i < col.Count; i++)
            {
               
                ds.Tables[0].Rows.Add(col[i].ToString(), "1");
            }
            ds.WriteXml(@"D:\ResumeSettings\Email.xml");
            MessageBox.Show("You will not receive mails from the selected Email-Id's","ResumeParser");
        }

     
    }
}