GUI Windows Form C#

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
public class Form1 : System.Windows.Forms.Form {
    private System.Windows.Forms.TextBox textBox1;
    private System.Windows.Forms.VScrollBar vScrollBar1;
    int counter = 0;
    private System.Windows.Forms.Label label1;
    public Form1() {
        this.textBox1 = new System.Windows.Forms.TextBox();
        this.vScrollBar1 = new System.Windows.Forms.VScrollBar();
        this.label1 = new System.Windows.Forms.Label();
        this.SuspendLayout();
        this.textBox1.Font = new System.Drawing.Font("Microsoft Sans Serif", 12F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
        this.textBox1.ForeColor = System.Drawing.Color.Transparent;
        this.textBox1.Location = new System.Drawing.Point(24, 56);
        this.textBox1.Multiline = true;
        this.textBox1.ReadOnly = true;
        this.textBox1.Size = new System.Drawing.Size(144, 32);
        this.textBox1.TextAlign = System.Windows.Forms.HorizontalAlignment.Center;
        this.vScrollBar1.Location = new System.Drawing.Point(168, 56);
        this.vScrollBar1.Size = new System.Drawing.Size(16, 32);
        this.vScrollBar1.Scroll += new System.Windows.Forms.ScrollEventHandler(this.vScrollBar1_Scroll);
        this.label1.Location = new System.Drawing.Point(8, 16);
        this.label1.Size = new System.Drawing.Size(192, 16);
        this.label1.Text = "Numeric Scolling using VScroll Bars";
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
        this.ClientSize = new System.Drawing.Size(208, 109);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                      this.label1,
                                      this.vScrollBar1,
                                      this.textBox1});
        this.Text = "Numeric Scroll";
        this.Load += new System.EventHandler(this.Form1_Load);
        this.ResumeLayout(false);
    }
    [STAThread]
    static void Main() {
        Application.Run(new Form1());
    }
    private void textBox1_TextChanged(object sender, System.EventArgs e) {
    }
    private void Form1_Load(object sender, System.EventArgs e) {
        vScrollBar1.Maximum = 100;
        vScrollBar1.Minimum = 0;
        vScrollBar1.SmallChange = 1;
    }
    private void vScrollBar1_Scroll(object sender, System.Windows.Forms.ScrollEventArgs e) {
        if (e.Type == ScrollEventType.Last)
            counter = 100;
        if (e.Type == ScrollEventType.First)
            counter = 0;
        if (e.Type == ScrollEventType.SmallDecrement)
            counter--;
        if (e.Type == ScrollEventType.SmallIncrement) {
            counter++;
        } 
        if (e.Type == ScrollEventType.LargeDecrement)
            counter -= 5;
        if (e.Type == ScrollEventType.LargeIncrement) {
            counter += 5;
        } 
        if (e.Type == ScrollEventType.First)
            counter = 0;
        if (e.Type == ScrollEventType.Last)
            counter = 100;
        Console.WriteLine(e.NewValue + "\n");
        if (counter > 100) counter = 100;
        if (counter < 0) counter = 0;
        Console.WriteLine(counter.ToString());
    }
}