Dynamic Windows Control example that makes a GroupBox and adds items as needed

DynWinControls

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

namespace RandomSelector
{
    public partial class frmRandomSelector : Form
    {
        public List<string> prizes = new List<string>();
        public List<string> participants = new List<string>();
        public List<Label> prizeLabels = new List<Label>();
        public List<TextBox> winnerBoxes = new List<TextBox>();
        private string listboxInputFileName;
        private string categoryInputFileName;
        private string gbText;
        private string labelText;
        private string textBoxText;
        private GroupBox gbDynamicGroupBox;
        private Label lbl_TBDescriptions;
        private Label lbl_LabelDescriptions;

        public frmRandomSelector()
        {
            InitializeComponent();
            
            //The following lines ensure the Form grows with the dynamic content
            this.AutoSizeMode = AutoSizeMode.GrowAndShrink;
            this.AutoSize = true;
            this.Padding = new Padding(0, 0, 24 + bQuit.Width , 0);            
            
            //Load Content
            ReadArgs();
            LoadListBox();
            LoadCategories();

            //Load Dynamic Controls
            Dynamic_Components();
                        
        }

        #region Form Controls
        private void frmRandomSelector_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Escape)
            {
                this.Dispose();
            }
        }

        private void btnCancel_press(object sender, EventArgs e)
        {
            this.Dispose();
        }

        private void bSelect_Click(object sender, EventArgs e)
        {
            foreach (TextBox t in winnerBoxes)
            {
                //Instantiate a random number and seed it randomly for max randomness
                Random randIndex = new Random(Guid.NewGuid().GetHashCode());
                int r = randIndex.Next(0, participants.Count);
                t.Text = participants[r];
                participants.RemoveAt(r);
            }
        }

        #endregion

        #region Load Data

        private void LoadListBox(string inputFile = "inputParticipants.csv")
        {
            try
            {
                using (StreamReader sr = new StreamReader(listboxInputFileName))
                {
                    while (!sr.EndOfStream)
                    {
                        participants.Add(sr.ReadLine().Split(',')[0]);
                    }
                    lbItems.Items.AddRange(participants.ToArray());
                }
            }
            catch
            {
                lbItems.Items.Add("<No input file detected>");
                bSelect.Enabled = false;

            }
        }

        private void LoadCategories()
        {
            try
            {                
                //Read Input file for Category labels
                prizes.AddRange(new StreamReader(categoryInputFileName).ReadToEnd().Replace("\r\n", "\r").Split('\r'));
            }
            catch
            {
                Label warningLabel = new Label();
                warningLabel.Location = new Point(lbItems.Left, lbItems.Bottom + 24);
                warningLabel.AutoSize = true;
                warningLabel.ForeColor = Color.Red;
                warningLabel.Text = "No Category Input File Found";                
                this.Controls.Add(warningLabel);
            }
        }

        private void ReadArgs()
        {
            //Predefine string values to avoid nulls
            gbText = "<group box description>";
            labelText = "<categories>";
            textBoxText = "<random content>";
            listboxInputFileName = "inputParticipants.csv";
            categoryInputFileName = "input.txt";

            //Parse through Args
            string[] args = Environment.GetCommandLineArgs();
            for (int i = 1; i < args.Length; i++ )
            {
                string arg = args[i];

                //split the argument
                string key = arg.Split('=')[0].ToLower();
                string value = arg.Split('=')[1];

                if (key == "selectionfile")
                {
                    listboxInputFileName = value;
                }
                else if (key == "categoryfile")
                {
                    categoryInputFileName = value;
                }
                else if (key == "gbtext")
                {
                    gbText = value;
                }
                else if (key == "label")
                {
                    labelText = value;
                }
                else if (key == "text")
                {
                    textBoxText = value;
                }
            }
        }

        private void Dynamic_Components()
        {
            //Instantiate Controls
            gbDynamicGroupBox = new GroupBox();
            lbl_TBDescriptions = new Label();
            lbl_LabelDescriptions = new Label();

            //Add Static Labels inside Group Box
            this.gbDynamicGroupBox.Controls.Add(this.lbl_TBDescriptions);
            this.gbDynamicGroupBox.Controls.Add(this.lbl_LabelDescriptions);
            lbl_TBDescriptions.Text = textBoxText;
            lbl_TBDescriptions.Location = new Point(8, 20);

            lbl_LabelDescriptions.Text = labelText;
            lbl_LabelDescriptions.Location = new Point(200, 20);

            for (int i = 0; i < prizes.Count; i++)
            {
                Label dynLabel = new Label();
                TextBox dynTextBox = new TextBox();

                //Set up dynamic Textbox
                dynTextBox.Location = new Point(8, (lbl_TBDescriptions.Bottom + (i * 24)));
                dynTextBox.Size = new Size(185, 20);
                //Set up Dynamic Labels
                dynLabel.Text = prizes[i];
                dynLabel.Location = new Point((dynTextBox.Right + 12), (dynTextBox.Top + 6));
                dynLabel.AutoSize = true;

                //Add to Lists
                winnerBoxes.Add(dynTextBox);
                prizeLabels.Add(dynLabel);

                //Add to GroupBox
                this.gbDynamicGroupBox.Controls.Add(dynTextBox);
                this.gbDynamicGroupBox.Controls.Add(dynLabel);
            }

            this.gbDynamicGroupBox.Location = new Point(288, 14);
            this.gbDynamicGroupBox.Size = new Size(264, 100);
            this.gbDynamicGroupBox.AutoSizeMode = AutoSizeMode.GrowAndShrink;
            this.gbDynamicGroupBox.AutoSize = true;
            this.gbDynamicGroupBox.Padding = new Padding(0, 0, 0, 0);
            this.gbDynamicGroupBox.Text = gbText;
            this.Controls.Add(gbDynamicGroupBox);

            int bsX = this.Width - (bSelect.Width + 24);
            int bsY = this.Height - (bSelect.Height + 48 + bQuit.Height);

            int bqX = this.Width - (bQuit.Width + 24);
            int bqY = this.Height - (bQuit.Height + 48);
            
            bSelect.Location = new Point(bsX, bsY);
            bQuit.Location = new Point(bqX, bqY);
        }
        #endregion
    }
}