Вывести соответствующее сообщение о структуре Train - C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
 
namespace WindowsFormsApplication4
{
    public partial class Form1 : Form
    {
        struct Train
        {
            public string punkt;
            public int nomer;
            public double time;
 
        }
        Train[] train = new Train[100];
        int countrain = 0;
        public Form1()
        {
            InitializeComponent();
        }
 
        private void button1_Click(object sender, EventArgs e)
        {

            listBox1.Items.Clear();
            for (int i=0; i<100; i++)
            {
                if (train[i].time > 0)
                {
                    
                   listBox1.Items.Add("Пункт" + " " + train[i].punkt + " " + "Номер поезда"+" " + train[i].nomer + " " + "Время" + " " + train[i].time);
                }
            }

        }
 
        private void button2_Click(object sender, EventArgs e)
        {
 
            train[countrain].punkt = Convert.ToString(textBox1.Text);
            train[countrain].nomer = Convert.ToInt32(textBox2.Text);
            train[countrain].time = Convert.ToDouble(textBox3.Text);
            countrain++;
            textBox1.Text = "";
            textBox2.Text = "";
            textBox3.Text = "";
            textBox5.Text = " ";
        }
 
        private void label1_Click(object sender, EventArgs e)
        {
 
        }
 
        private void button3_Click(object sender, EventArgs e)
        {
            textBox5.Text = " ";
            listBox2.Items.Clear();
            String p;
            p = Convert.ToString(textBox4.Text);
            for (int i = 0; i < 100; i++)
            {
                if (p == train[i].punkt)
                {
 
                    listBox2.Items.Add("Пункт" + " " + train[i].punkt + " " + "Номер поезда" + " " + train[i].nomer + " " + "Время" + " " + train[i].time);
                }
               
                //вывод сообщения
                if (p == train[i].punkt)
 
                    textBox5.Text = ("");
                { 
                    
                    if (p != train[i].punkt)
 
                    textBox5.Text = ("error");
                }

            }
        }
 
        private void button4_Click(object sender, EventArgs e)
        {
            textBox1.Text = "";
            textBox2.Text = "";
            textBox3.Text = "";
            textBox4.Text = "";
            listBox1.Items.Clear();
            listBox2.Items.Clear();
        }
 
        private void button5_Click(object sender, EventArgs e)
        {
            Environment.Exit(0);
        }
 
        private void Form1_Load(object sender, EventArgs e)
        {
 
        }
    }
}