C#

<br />
using System;<br />
using System.Drawing;<br />
using System.Collections;<br />
using System.ComponentModel;<br />
using System.Windows.Forms;<br />
<br />
namespace WinApp<br />
{<br />
	/// <summary><br />
	/// Summary description for frmAspect.<br />
	/// </summary><br />
	public class frmAspect : System.Windows.Forms.Form<br />
	{<br />
		private int StartX = 0, StartY = 0, EndX = 0, EndY = 0;<br />
		private bool bMouseDown = false;<br />
		Rectangle rctRubber = Rectangle.Empty;<br />
		<br />
<br />
		private System.Windows.Forms.PictureBox pb;<br />
		private System.Windows.Forms.Label lblMessage;<br />
		/// <summary><br />
		/// Required designer variable.<br />
		/// </summary><br />
		private System.ComponentModel.Container components = null;<br />
<br />
		public frmAspect()<br />
		{<br />
			//<br />
			// Required for Windows Form Designer support<br />
			//<br />
			InitializeComponent();<br />
<br />
			//<br />
			// TODO: Add any constructor code after InitializeComponent call<br />
			//<br />
		}<br />
<br />
		/// <summary><br />
		/// Clean up any resources being used.<br />
		/// </summary><br />
		protected override void Dispose( bool disposing )<br />
		{<br />
			if( disposing )<br />
			{<br />
				if(components != null)<br />
				{<br />
					components.Dispose();<br />
				}<br />
			}<br />
			base.Dispose( disposing );<br />
		}<br />
<br />
		#region Windows Form Designer generated code<br />
		/// <summary><br />
		/// Required method for Designer support - do not modify<br />
		/// the contents of this method with the code editor.<br />
		/// </summary><br />
		private void InitializeComponent()<br />
		{<br />
			this.pb = new System.Windows.Forms.PictureBox();<br />
			this.lblMessage = new System.Windows.Forms.Label();<br />
			this.SuspendLayout();<br />
			// <br />
			// pb<br />
			// <br />
			this.pb.Location = new System.Drawing.Point(16, 56);<br />
			this.pb.Name = "pb";<br />
			this.pb.Size = new System.Drawing.Size(336, 256);<br />
			this.pb.TabIndex = 0;<br />
			this.pb.TabStop = false;<br />
			this.pb.Paint += new System.Windows.Forms.PaintEventHandler(this.pb_Paint);<br />
			this.pb.MouseUp += new System.Windows.Forms.MouseEventHandler(this.pb_MouseUp);<br />
			this.pb.MouseMove += new System.Windows.Forms.MouseEventHandler(this.pb_MouseMove);<br />
			this.pb.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pb_MouseDown);<br />
			// <br />
			// lblMessage<br />
			// <br />
			this.lblMessage.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;<br />
			this.lblMessage.Location = new System.Drawing.Point(368, 0);<br />
			this.lblMessage.Name = "lblMessage";<br />
			this.lblMessage.Size = new System.Drawing.Size(288, 256);<br />
			this.lblMessage.TabIndex = 1;<br />
			// <br />
			// frmAspect<br />
			// <br />
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);<br />
			this.ClientSize = new System.Drawing.Size(680, 566);<br />
			this.Controls.Add(this.lblMessage);<br />
			this.Controls.Add(this.pb);<br />
			this.Name = "frmAspect";<br />
			this.Text = "frmAspect";<br />
			this.Load += new System.EventHandler(this.frmAspect_Load);<br />
			this.ResumeLayout(false);<br />
<br />
		}<br />
		#endregion<br />
<br />
		private void frmAspect_Load(object sender, System.EventArgs e)<br />
		{<br />
			pb.Image = Image.FromFile( @"C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures\Water lilies.jpg");<br />
			pb.SizeMode = PictureBoxSizeMode.StretchImage;<br />
		}<br />
<br />
		private void pb_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)<br />
		{<br />
			pb.Cursor = Cursors.Cross;<br />
			rctRubber.X = e.X;<br />
			rctRubber.Y = e.Y;<br />
			Cursor.Clip = pb.RectangleToScreen(pb.ClientRectangle);<br />
			bMouseDown = true;<br />
		}<br />
<br />
		private void pb_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)<br />
		{<br />
			Cursor.Clip = Rectangle.Empty;<br />
			bMouseDown = false;<br />
			pb.Cursor = Cursors.Default;<br />
		}<br />
<br />
		private void pb_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)<br />
		{<br />
			if (bMouseDown == false) {return;}<br />
			pb.Cursor = Cursors.Cross;<br />
			rctRubber.Width = Math.Max(e.X,rctRubber.X) - rctRubber.X;<br />
			rctRubber.Height = Math.Max(e.Y, rctRubber.Y) - rctRubber.Y;<br />
			<br />
			pb.Invalidate();<br />
			<br />
		}<br />
<br />
		private void pb_Paint(object sender, System.Windows.Forms.PaintEventArgs e)<br />
		{<br />
			if (bMouseDown == false)<br />
			{<br />
				return;<br />
			}<br />
			<br />
		<br />
			<br />
			<br />
			<br />
			//rctRubber.Height = Convert.ToInt16(rctRubber.Width * 1.37); <br />
<br />
<br />
<br />
			lblMessage.Text = "PB ClientRectange: " + pb.ClientRectangle.ToString()+ "\n" +<br />
							"Rubber Rectangle: " + rctRubber.ToString();<br />
		<br />
<br />
<br />
			<br />
			Pen pen = new Pen(Color.Red, 2);<br />
			pen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;<br />
<br />
			e.Graphics.DrawRectangle(pen,rctRubber);<br />
<br />
<br />
		}<br />
	}<br />
}<br />

<br />
using System.Runtime.InteropServices;<br />
<br />
private const int WM_SCROLL = 276; // Horizontal scroll<br />
private const int WM_VSCROLL = 277; // Vertical scroll<br />
private const int SB_LINEUP = 0; // Scrolls one line up<br />
private const int SB_LINELEFT = 0;// Scrolls one cell left<br />
private const int SB_LINEDOWN = 1; // Scrolls one line down<br />
private const int SB_LINERIGHT = 1;// Scrolls one cell right<br />
private const int SB_PAGEUP = 2; // Scrolls one page up<br />
private const int SB_PAGELEFT = 2;// Scrolls one page left<br />
private const int SB_PAGEDOWN = 3; // Scrolls one page down<br />
private const int SB_PAGERIGTH = 3; // Scrolls one page right<br />
private const int SB_PAGETOP = 6; // Scrolls to the upper left<br />
private const int SB_LEFT = 6; // Scrolls to the left<br />
private const int SB_PAGEBOTTOM = 7; // Scrolls to the upper right<br />
private const int SB_RIGHT = 7; // Scrolls to the right<br />
private const int SB_ENDSCROLL = 8; // Ends scroll<br />
<br />
[DllImport("user32.dll",CharSet=CharSet.Auto)]<br />
private static extern int SendMessage(IntPtr hWnd, int wMsg,IntPtr wParam, IntPtr lParam);<br />