form1.cs

《c#技术内幕代码》

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

namespace ch11_5
{
	/// <summary>
	/// Summary description for Form1.
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;
		private Boolean fMouseDown;
		private ArrayList fPoints;

		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();

			//
			// TODO: Add any constructor code after InitializeComponent call
			//
			fPoints = new ArrayList();
		}

		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(824, 621);
			this.Name = "Form1";
			this.Text = "Form1";
			this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.OnMouseDown);
			this.MouseUp += new System.Windows.Forms.MouseEventHandler(this.OnMouseUp);
			this.Paint += new System.Windows.Forms.PaintEventHandler(this.OnPaint);
			this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.OnMouseMove);

		}
		#endregion

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void OnMouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			fMouseDown = true;

			// Clear the array of points
			fPoints.Clear();

			// Add a new point
			Point p = new Point();
			p.X = e.X;
			p.Y = e.Y;
			fPoints.Add( p );
		}

		private void OnMouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if ( fMouseDown )
			{
				// Add a new point to the array
				Point p = new Point();
				p.X = e.X;
				p.Y = e.Y;
				fPoints.Add( p );

				// And redraw
				this.Refresh();

			}

		}

		private void OnMouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			// Add this point
			Point p = new Point();
			p.X = e.X;
			p.Y = e.Y;
			fPoints.Add( p );

			// Redraw
			this.Refresh();

			// And stop collecting points
			fMouseDown = false;

		}

		private void OnPaint(object sender, System.Windows.Forms.PaintEventArgs e)
		{
			// Move to the first point
			System.Collections.IEnumerator myEnumerator = fPoints.GetEnumerator();
			Pen pen1 = new Pen(Color.FromArgb(150, Color.Purple));
			if ( myEnumerator.MoveNext() )
			{
				Point p1 = (Point)myEnumerator.Current;
				while ( myEnumerator.MoveNext() )
				{
					Point p2 = (Point)myEnumerator.Current;
					e.Graphics.DrawLine(pen1, p1, p2);
					p1 = p2;
				}
			}
		}
	}
}