password generator

Question

i am writing a passowrd generator and want to include an external .txt file for the words for the passwerds.

this is the code using strings so far:

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

namespace PasswordGenerator
{
    public partial class frmPasswordGenerator : Form
    {
        public frmPasswordGenerator()
        {
            InitializeComponent();
        }

        private void btnGenerate_Click(object sender, EventArgs e)
        {
            txtOutput.Text = "";

            int NumberOfPasswords = int.Parse(txtNumPass.Text);
            int PasswordLength = int.Parse(txtLength.Text);

            for (int i = 0; i < NumberOfPasswords; i++) 
            {
                for (int g = 0; g < PasswordLength; g++)
                {
                    txtOutput.Text += GetCharacter();
                   
                }
                txtOutput.Text += "\r\n"; 
            }
        }
        private string GetCharacter()
        {

            string[] Lower = new string[4] { "dog", "badger", "monkey", "trumpet" };
            string[] Upper = new string[10] { "apple", "cow", "operation", "onion", "peach", "qwerty", "wendy", "ronald", "mac", "chimney" };
            string[] Number = new string[10] { "1", "2", "3", "4", "5", "6", "7", "8", "9", "0" };

 

            Random rand = new System.Random(Guid.NewGuid().GetHashCode());
            int rplace = rand.Next(0, 3);
            int rplace2 = 0;

            {
                rplace = rand.Next(0, 3);
            }
            switch (rplace)
            {
                case 0:
                    rplace2 = rand.Next(0, 4);
                    return Lower[rplace2];
                case 1:
                    rplace2 = rand.Next(0, 10);
                    return Upper[rplace2];
                case 2:
                    rplace2 = rand.Next(0, 10);
                    return Number[rplace2];
                default:
                    return "";

            }
        }

        private void frmPasswordGenerator_Load(object sender, EventArgs e)
        {

        }

        private void cbLower_CheckedChanged(object sender, EventArgs e)
        {

        }
    }
}