GUI Windows Forms C# Tutorial

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    private void showLinesButton_Click(object sender, EventArgs e)
    {
        StringBuilder lineInfo = new StringBuilder();
        lineInfo.Append("There are " + multiLineBox.Lines.Length.ToString() + " lines.\n");
        foreach (string line in multiLineBox.Lines)
        {
            lineInfo.Append(line + "\n");
        }
        MessageBox.Show(lineInfo.ToString());
    }
}
partial class Form1
{
    private void InitializeComponent()
    {
        this.multiLineBox = new System.Windows.Forms.TextBox();
        this.showLinesButton = new System.Windows.Forms.Button();
        this.SuspendLayout();
        // 
        // multiLineBox
        // 
        this.multiLineBox.Location = new System.Drawing.Point(12, 12);
        this.multiLineBox.Multiline = true;
        this.multiLineBox.Name = "multiLineBox";
        this.multiLineBox.Size = new System.Drawing.Size(268, 213);
        this.multiLineBox.TabIndex = 0;
        // 
        // showLinesButton
        // 
        this.showLinesButton.Location = new System.Drawing.Point(205, 231);
        this.showLinesButton.Name = "showLinesButton";
        this.showLinesButton.Size = new System.Drawing.Size(75, 23);
        this.showLinesButton.TabIndex = 1;
        this.showLinesButton.Text = "Show Lines";
        this.showLinesButton.Click += new System.EventHandler(this.showLinesButton_Click);
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(292, 266);
        this.Controls.Add(this.showLinesButton);
        this.Controls.Add(this.multiLineBox);
        this.Name = "Form1";
        this.Text = "Form1";
        this.ResumeLayout(false);
        this.PerformLayout();
    }
    private System.Windows.Forms.TextBox multiLineBox;
    private System.Windows.Forms.Button showLinesButton;
}
public class TextBoxLineCountText
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new Form1());
    }
}