C#

public Artist GetArtistData()
        {
            // Attempt to initialize a new 'Session' object; alert user and exit on error
            Artist newArtist;
            if (null == (newArtist = new Artist()))
                return null;

            // Set the necessary value for each property in the artist object
            newArtist.UniqueId = txtUniqueId.Text;
            newArtist.StageName = txtStageName.Text;
            newArtist.FirstName = txtFirstName.Text;
            newArtist.LastName = txtLastName.Text;
            newArtist.PrimaryPhone = txtPrimaryPhone.Text;
            newArtist.SecondaryPhone = txtSecondaryPhone.Text;
            newArtist.Email = txtEmail.Text;
            newArtist.HomePageUrl = homePageLink.Text;
            newArtist.MyspaceUrl = myspaceLink.Text;
            newArtist.SoundclickUrl = soundclickLink.Text;
            newArtist.HourlySessionRate = txtRecordingRate.Text;
            newArtist.Notes = txtNotes.Text;

            if (sessionsList.Items.Count > 0)    // We have sessions
            {
                foreach (ListViewItem session in sessionsList.Items)
                    newArtist.SessionIdList.Add(session.SubItems[0].Text);
            }

            return newArtist;
        }

        public bool IsSelectionValid()
        {
            // Selection is valid
            if ((artistsTree.Nodes[0].Nodes.Count > 0) && (artistsTree.SelectedNode.Level > 0))
                return true;
            else    // Invalid
                return false;
        }

private void btnDelete_Click(object sender, EventArgs e)
        {
            Artist artist;
            if ((null != (artist = GetArtistData())) && (IsSelectionValid()))
            {
                DialogResult result = MessageBox.Show("Are you sure you want to delete the artist named \"" +
                    artist.StageName + "\"? This operation cannot be undone.", "L.M.E. - Delete Session",
                    MessageBoxButtons.YesNo, MessageBoxIcon.Error);

                // The user confirmed the choice to delete the artist
                if (result == DialogResult.Yes)
                {
                    MainForm parentForm;
                    if (null != (parentForm = (MainForm)this.MdiParent))
                    {
                        if (parentForm.DeleteArtist(artist))
                        {
                            // Remove the active artist from the tree
                            if (artist.UniqueId != string.Empty)
                            {
                                TreeNode node = artistsTree.SelectedNode;
                                if (node != null)
                                {
                                    artistsTree.Nodes[0].Nodes.Remove(node);
                                    // artistsTree.SelectedNode = artistsTree.Nodes[0];

                                    if (Artists.Count == 0)
                                        System.Diagnostics.Debug.WriteLine("Artists.Count = 0");

                                    foreach (Artist a in Artists)    // Loop through current artists
                                    {
                                        System.Diagnostics.Debug.WriteLine("Unique ID: " + a.UniqueId);
                                        if (a.UniqueId == artist.UniqueId)    // Found a match; remove the artist from the list
                                        {
                                            System.Diagnostics.Debug.WriteLine("Removed: " + a.UniqueId);
                                            System.Diagnostics.Debug.Write("\tArtist ID:" + artist.UniqueId);
                                            Artists.Remove(a);
                                            return;
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

public bool DeleteArtist(Artist artistData)
        {
            if ((recordLabel == null) || (recordLabel.Artists == null) || (recordLabel.Artists.Count == 0))
                return false;

            // Find the artist in the current list
            foreach (Artist artist in recordLabel.Artists)
            {
                if (artist.UniqueId == artistData.UniqueId)
                {
                    recordLabel.Artists.Remove(artist);

                    // Save the label data
                    switch (recordLabel.SaveDataToDisk(CurrentDataFilePath))
                    {
                        case IoErrorCode.NoError:    // Notify the user that the file was saved successfully
                            sessionTimerForm.Artists = recordLabel.Artists;
                            sessionsForm.ClearArtistsList();
                            sessionsForm.Artists = recordLabel.Artists;

                            sessionTimerForm.RemoveArtist(artistData.StageName);

                            currentActionStatus.Text = "Data saved successfully.";
                            currentActionStatus.Image = Lab_Management_Environment.Properties.Resources.preferences;
                            return true;
                        default:
                            return false;
                    }
                }
            }

            return false;
        }

if (parentForm.DeleteArtist(artist))
                        {
                            // Remove the active artist from the tree
                            if (artist.UniqueId != string.Empty)
                            {
                                TreeNode node = artistsTree.SelectedNode;
                                if (node != null)
                                {
                                    artistsTree.Nodes[0].Nodes.Remove(node);
                                    // artistsTree.SelectedNode = artistsTree.Nodes[0];

                                    if (Artists.Count == 0)
                                        System.Diagnostics.Debug.WriteLine("Artists.Count = 0");

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 Construction_Survey_Layout
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        // PN is the index. I didn't set it to 0 because I want it to retain it's value
        // It is at 0 the first time run.
        public int PN;

        private void btnNew_Click(object sender, EventArgs e)
        {
            ArrayList Projects = new ArrayList();            
            // The error was directed at PN here.
            Projects[PN] = textBoxAddNew.ToString();

            Projects.Add(Projects[PN]);
                                    
            textBoxAddNew.Clear();

            Projects.Sort();

            for(int ctr = 0; ctr <= PN; ctr++)
            {
                listBox1.Items.Add(Projects[ctr]);                
            }
            PN++;
            
            // The following is the error message I got after entering a Project Name in the text box
            // and clicked the Add New button:
            //Index was out of range. Must be non-negative and less than the size of the collection.
            //  Parameter name: index
        }

        
    }
}