A Calculator Control Box

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Globalization;
namespace Calculator
{
	/// <summary>
	/// Summary description for frmCalculator.
	/// </summary>
	public class frmCalculator : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Button btnEight;
		private System.Windows.Forms.Button btnNine;
		private System.Windows.Forms.Button btnDivide;
		private System.Windows.Forms.Button btnSeven;
		private System.Windows.Forms.Button btnFive;
		private System.Windows.Forms.Button btnSix;
		private System.Windows.Forms.Button btnMultiply;
		private System.Windows.Forms.Button btnFour;
		private System.Windows.Forms.Button btnDot;
		private System.Windows.Forms.Button btnPlusMinus;
		private System.Windows.Forms.Button btnPlus;
		private System.Windows.Forms.Button btnZero;
		private System.Windows.Forms.Button btnTwo;
		private System.Windows.Forms.Button btnThree;
		private System.Windows.Forms.Button btnMinus;
		private System.Windows.Forms.Button btnOne;
		private System.Windows.Forms.Button btnBack;
		private System.Windows.Forms.Button btnEqual;
		private System.Windows.Forms.Button btnClear;
		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public delegate void ValueChangedEvent(object sender, double value);
		public event ValueChangedEvent ValueChanged=null; 
		public event KeyPressEventHandler NumberKeyPressed=null;
		public delegate void ErrorEvent(object sender, string Message);
		public event ErrorEvent ErrorOccured=null;

		private string clickedOperator="";
		private double firstValue;
		private double previousValue;
		public frmCalculator()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();
			//
			// TODO: Add any constructor code after InitializeComponent call
			//
			this.btnDot.Text=CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator;

		}

		/// <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()
		{
			this.btnEight = new System.Windows.Forms.Button();
			this.btnNine = new System.Windows.Forms.Button();
			this.btnDivide = new System.Windows.Forms.Button();
			this.btnSeven = new System.Windows.Forms.Button();
			this.btnFive = new System.Windows.Forms.Button();
			this.btnSix = new System.Windows.Forms.Button();
			this.btnMultiply = new System.Windows.Forms.Button();
			this.btnFour = new System.Windows.Forms.Button();
			this.btnDot = new System.Windows.Forms.Button();
			this.btnPlusMinus = new System.Windows.Forms.Button();
			this.btnPlus = new System.Windows.Forms.Button();
			this.btnZero = new System.Windows.Forms.Button();
			this.btnTwo = new System.Windows.Forms.Button();
			this.btnThree = new System.Windows.Forms.Button();
			this.btnMinus = new System.Windows.Forms.Button();
			this.btnOne = new System.Windows.Forms.Button();
			this.btnBack = new System.Windows.Forms.Button();
			this.btnEqual = new System.Windows.Forms.Button();
			this.btnClear = new System.Windows.Forms.Button();
			this.SuspendLayout();
			// 
			// btnEight
			// 
			this.btnEight.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnEight.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnEight.Location = new System.Drawing.Point(32, 19);
			this.btnEight.Name = "btnEight";
			this.btnEight.Size = new System.Drawing.Size(20, 20);
			this.btnEight.TabIndex = 7;
			this.btnEight.TabStop = false;
			this.btnEight.Text = "8";
			this.btnEight.Click += new System.EventHandler(this.btnEight_Click);
			this.btnEight.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnNine
			// 
			this.btnNine.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnNine.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnNine.Location = new System.Drawing.Point(54, 19);
			this.btnNine.Name = "btnNine";
			this.btnNine.Size = new System.Drawing.Size(20, 20);
			this.btnNine.TabIndex = 6;
			this.btnNine.TabStop = false;
			this.btnNine.Text = "9";
			this.btnNine.Click += new System.EventHandler(this.btnNine_Click);
			this.btnNine.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnDivide
			// 
			this.btnDivide.BackColor = System.Drawing.Color.DarkGray;
			this.btnDivide.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnDivide.Location = new System.Drawing.Point(76, 19);
			this.btnDivide.Name = "btnDivide";
			this.btnDivide.Size = new System.Drawing.Size(20, 20);
			this.btnDivide.TabIndex = 5;
			this.btnDivide.TabStop = false;
			this.btnDivide.Text = "/";
			this.btnDivide.Click += new System.EventHandler(this.btnDivide_Click);
			this.btnDivide.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnSeven
			// 
			this.btnSeven.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnSeven.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnSeven.Location = new System.Drawing.Point(10, 19);
			this.btnSeven.Name = "btnSeven";
			this.btnSeven.Size = new System.Drawing.Size(20, 20);
			this.btnSeven.TabIndex = 4;
			this.btnSeven.TabStop = false;
			this.btnSeven.Text = "7";
			this.btnSeven.Click += new System.EventHandler(this.btnSeven_Click);
			this.btnSeven.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnFive
			// 
			this.btnFive.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnFive.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnFive.Location = new System.Drawing.Point(32, 41);
			this.btnFive.Name = "btnFive";
			this.btnFive.Size = new System.Drawing.Size(20, 20);
			this.btnFive.TabIndex = 11;
			this.btnFive.TabStop = false;
			this.btnFive.Text = "5";
			this.btnFive.Click += new System.EventHandler(this.btnFive_Click);
			this.btnFive.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnSix
			// 
			this.btnSix.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnSix.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnSix.Location = new System.Drawing.Point(54, 41);
			this.btnSix.Name = "btnSix";
			this.btnSix.Size = new System.Drawing.Size(20, 20);
			this.btnSix.TabIndex = 10;
			this.btnSix.TabStop = false;
			this.btnSix.Text = "6";
			this.btnSix.Click += new System.EventHandler(this.btnSix_Click);
			this.btnSix.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnMultiply
			// 
			this.btnMultiply.BackColor = System.Drawing.Color.DarkGray;
			this.btnMultiply.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnMultiply.Location = new System.Drawing.Point(76, 41);
			this.btnMultiply.Name = "btnMultiply";
			this.btnMultiply.Size = new System.Drawing.Size(20, 20);
			this.btnMultiply.TabIndex = 9;
			this.btnMultiply.TabStop = false;
			this.btnMultiply.Text = "*";
			this.btnMultiply.Click += new System.EventHandler(this.btnMultiply_Click);
			this.btnMultiply.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnFour
			// 
			this.btnFour.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnFour.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnFour.Location = new System.Drawing.Point(10, 41);
			this.btnFour.Name = "btnFour";
			this.btnFour.Size = new System.Drawing.Size(20, 20);
			this.btnFour.TabIndex = 8;
			this.btnFour.TabStop = false;
			this.btnFour.Text = "4";
			this.btnFour.Click += new System.EventHandler(this.btnFour_Click);
			this.btnFour.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnDot
			// 
			this.btnDot.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnDot.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnDot.Location = new System.Drawing.Point(32, 85);
			this.btnDot.Name = "btnDot";
			this.btnDot.Size = new System.Drawing.Size(20, 20);
			this.btnDot.TabIndex = 19;
			this.btnDot.TabStop = false;
			this.btnDot.Text = ".";
			this.btnDot.Click += new System.EventHandler(this.btnDot_Click);
			this.btnDot.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnPlusMinus
			// 
			this.btnPlusMinus.BackColor = System.Drawing.Color.DarkGray;
			this.btnPlusMinus.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnPlusMinus.Location = new System.Drawing.Point(54, 85);
			this.btnPlusMinus.Name = "btnPlusMinus";
			this.btnPlusMinus.Size = new System.Drawing.Size(20, 20);
			this.btnPlusMinus.TabIndex = 18;
			this.btnPlusMinus.TabStop = false;
			this.btnPlusMinus.Text = "�";
			this.btnPlusMinus.Click += new System.EventHandler(this.btnPlusMinus_Click);
			this.btnPlusMinus.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnPlus
			// 
			this.btnPlus.BackColor = System.Drawing.Color.DarkGray;
			this.btnPlus.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnPlus.Location = new System.Drawing.Point(76, 85);
			this.btnPlus.Name = "btnPlus";
			this.btnPlus.Size = new System.Drawing.Size(20, 20);
			this.btnPlus.TabIndex = 17;
			this.btnPlus.TabStop = false;
			this.btnPlus.Text = "+";
			this.btnPlus.Click += new System.EventHandler(this.btnPlus_Click);
			this.btnPlus.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnZero
			// 
			this.btnZero.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnZero.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnZero.Location = new System.Drawing.Point(10, 85);
			this.btnZero.Name = "btnZero";
			this.btnZero.Size = new System.Drawing.Size(20, 20);
			this.btnZero.TabIndex = 16;
			this.btnZero.TabStop = false;
			this.btnZero.Text = "0";
			this.btnZero.Click += new System.EventHandler(this.btnZero_Click);
			this.btnZero.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnTwo
			// 
			this.btnTwo.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnTwo.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnTwo.Location = new System.Drawing.Point(32, 63);
			this.btnTwo.Name = "btnTwo";
			this.btnTwo.Size = new System.Drawing.Size(20, 20);
			this.btnTwo.TabIndex = 15;
			this.btnTwo.TabStop = false;
			this.btnTwo.Text = "2";
			this.btnTwo.Click += new System.EventHandler(this.btnTwo_Click);
			this.btnTwo.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnThree
			// 
			this.btnThree.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnThree.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnThree.Location = new System.Drawing.Point(54, 63);
			this.btnThree.Name = "btnThree";
			this.btnThree.Size = new System.Drawing.Size(20, 20);
			this.btnThree.TabIndex = 14;
			this.btnThree.TabStop = false;
			this.btnThree.Text = "3";
			this.btnThree.Click += new System.EventHandler(this.btnThree_Click);
			this.btnThree.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnMinus
			// 
			this.btnMinus.BackColor = System.Drawing.Color.DarkGray;
			this.btnMinus.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnMinus.Location = new System.Drawing.Point(76, 63);
			this.btnMinus.Name = "btnMinus";
			this.btnMinus.Size = new System.Drawing.Size(20, 20);
			this.btnMinus.TabIndex = 13;
			this.btnMinus.TabStop = false;
			this.btnMinus.Text = "-";
			this.btnMinus.Click += new System.EventHandler(this.btnMinus_Click);
			this.btnMinus.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnOne
			// 
			this.btnOne.BackColor = System.Drawing.Color.WhiteSmoke;
			this.btnOne.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnOne.Location = new System.Drawing.Point(10, 63);
			this.btnOne.Name = "btnOne";
			this.btnOne.Size = new System.Drawing.Size(20, 20);
			this.btnOne.TabIndex = 12;
			this.btnOne.TabStop = false;
			this.btnOne.Text = "1";
			this.btnOne.Click += new System.EventHandler(this.btnOne_Click);
			this.btnOne.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnBack
			// 
			this.btnBack.BackColor = System.Drawing.Color.OliveDrab;
			this.btnBack.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnBack.Font = new System.Drawing.Font("Microsoft Sans Serif", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
			this.btnBack.Location = new System.Drawing.Point(32, 107);
			this.btnBack.Name = "btnBack";
			this.btnBack.Size = new System.Drawing.Size(20, 20);
			this.btnBack.TabIndex = 22;
			this.btnBack.TabStop = false;
			this.btnBack.Text = "<";
			this.btnBack.Click += new System.EventHandler(this.btnBack_Click);
			this.btnBack.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnEqual
			// 
			this.btnEqual.BackColor = System.Drawing.Color.DarkGray;
			this.btnEqual.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnEqual.Location = new System.Drawing.Point(54, 107);
			this.btnEqual.Name = "btnEqual";
			this.btnEqual.Size = new System.Drawing.Size(42, 20);
			this.btnEqual.TabIndex = 21;
			this.btnEqual.TabStop = false;
			this.btnEqual.Text = "=";
			this.btnEqual.Click += new System.EventHandler(this.btnEqual_Click);
			this.btnEqual.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// btnClear
			// 
			this.btnClear.BackColor = System.Drawing.Color.OliveDrab;
			this.btnClear.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
			this.btnClear.Location = new System.Drawing.Point(10, 107);
			this.btnClear.Name = "btnClear";
			this.btnClear.Size = new System.Drawing.Size(20, 20);
			this.btnClear.TabIndex = 20;
			this.btnClear.TabStop = false;
			this.btnClear.Text = "C";
			this.btnClear.Click += new System.EventHandler(this.btnClear_Click);
			this.btnClear.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			// 
			// frmCalculator
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.BackColor = System.Drawing.SystemColors.Control;
			this.ClientSize = new System.Drawing.Size(104, 136);
			this.Controls.Add(this.btnBack);
			this.Controls.Add(this.btnEqual);
			this.Controls.Add(this.btnClear);
			this.Controls.Add(this.btnDot);
			this.Controls.Add(this.btnPlusMinus);
			this.Controls.Add(this.btnPlus);
			this.Controls.Add(this.btnZero);
			this.Controls.Add(this.btnTwo);
			this.Controls.Add(this.btnThree);
			this.Controls.Add(this.btnMinus);
			this.Controls.Add(this.btnOne);
			this.Controls.Add(this.btnFive);
			this.Controls.Add(this.btnSix);
			this.Controls.Add(this.btnMultiply);
			this.Controls.Add(this.btnFour);
			this.Controls.Add(this.btnEight);
			this.Controls.Add(this.btnNine);
			this.Controls.Add(this.btnDivide);
			this.Controls.Add(this.btnSeven);
			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
			this.Name = "frmCalculator";
			this.ShowInTaskbar = false;
			this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
			this.Text = "frmCalculator";
			this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.frmCalculator_KeyDown);
			this.Load += new System.EventHandler(this.frmCalculator_Load);
			this.Leave += new System.EventHandler(this.CheckToHide);
			this.Deactivate += new System.EventHandler(this.CheckToHide);
			this.ResumeLayout(false);

		}
		#endregion
		
		protected override void OnResize(EventArgs e)
		{
			if(this.Height!=136)
				this.Height=136;
			if(this.Width!=104)
				this.Width=104;
			base.OnResize (e);
		}
		private void CheckToHide(object sender, EventArgs e)
		{
			startedNew=false;
			firstValue=0;
			this.Hide();
		}

		private void frmCalculator_KeyDown(object sender, KeyEventArgs e)
		{
			if(e.KeyData==Keys.Escape)
			{
				startedNew=false;
				firstValue=0;
				Value=previousValue;
				this.Hide();
			}
			switch(e.KeyData)
			{
				case Keys.D0:
				case Keys.NumPad0:
					OnNumberKeyPressed('0');
					break;
				case Keys.D1:
				case Keys.NumPad1:
					OnNumberKeyPressed('1');
					break;
				case Keys.D2:
				case Keys.NumPad2:
					OnNumberKeyPressed('2');
					break;
				case Keys.D3:
				case Keys.NumPad3:
					OnNumberKeyPressed('3');
					break;
				case Keys.D4:
				case Keys.NumPad4:
					OnNumberKeyPressed('4');
					break;
				case Keys.D5:
				case Keys.NumPad5:
					OnNumberKeyPressed('5');
					break;
				case Keys.D6:
				case Keys.NumPad6:
					OnNumberKeyPressed('6');
					break;
				case Keys.D7:
				case Keys.NumPad7:
					OnNumberKeyPressed('7');
					break;
				case Keys.D8:
				case Keys.NumPad8:
					OnNumberKeyPressed('8');
					break;
				case Keys.D9:
				case Keys.NumPad9:
					OnNumberKeyPressed('9');
					break;
				case Keys.Decimal:
					OnNumberKeyPressed(Convert.ToChar(CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator));
					break;
				case Keys.Enter:
					btnEqual_Click(this,new EventArgs());
					break;
				case Keys.Back:
					OnNumberKeyPressed(Convert.ToChar(8));
					break;
				case Keys.Add:
					OperationKeyPressed("+");
					break;
				case Keys.Divide:
					OperationKeyPressed("/");
					break;
				case Keys.Multiply:
					OperationKeyPressed("*");
					break;
				case Keys.Subtract:
					OperationKeyPressed("-");
					break;
			}
		}

		private void btnSeven_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('7');
		}

		private void btnEight_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('8');
		}

		private void btnNine_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('9');
		}
		private bool startedNew=false;
		private void OnNumberKeyPressed(char key)
		{
			if(startedNew==true)
			{
				if(key==Convert.ToChar(CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator))
				{
					Value=0;
					NumberKeyPressed(this,new KeyPressEventArgs(key));
					startedNew=false;
				}
				else
				{
					Value=double.Parse(key.ToString());
					startedNew=false;
				}
			}
			else
				if(NumberKeyPressed!=null)
					NumberKeyPressed(this,new KeyPressEventArgs(key));
		}

		private void btnDivide_Click(object sender, System.EventArgs e)
		{
			OperationKeyPressed("/");
		}
		private void OperationKeyPressed(string key)
		{
			if(startedNew==true)
				clickedOperator=key;
			PerformOperation();
			clickedOperator=key;
		}
		private void PerformOperation()
		{
			if(clickedOperator!="")
			{
				switch(clickedOperator)
				{
					case "/":
						if(Value!=0)
							Value=firstValue/Value;
						else if(ErrorOccured!=null)
						{
							ErrorOccured(this,"Error");
						}
						break;
					case "*":
						Value=firstValue*Value;
						break;
					case "-":
						Value=firstValue-Value;
						break;
					case "+":
						Value=firstValue+Value;
						break;
				}
			}
			startedNew=true;
			firstValue=Value;
		}
		private void btnFour_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('4');
		}

		private void btnFive_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('5');
		}

		private void btnSix_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('6');
		}

		private void btnMultiply_Click(object sender, System.EventArgs e)
		{
			OperationKeyPressed("*");
		}

		private void btnOne_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('1');
		}

		private void btnTwo_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('2');
		}

		private void btnThree_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('3');
		}

		private void btnMinus_Click(object sender, System.EventArgs e)
		{
			OperationKeyPressed("-");
		}

		private void btnZero_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed('0');
		}

		private void btnDot_Click(object sender, System.EventArgs e)
		{
			OnNumberKeyPressed(Convert.ToChar(CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator));
		}

		private void btnPlusMinus_Click(object sender, System.EventArgs e)
		{
			Value=-Value;
		}

		private void btnPlus_Click(object sender, System.EventArgs e)
		{
			OperationKeyPressed("+");
		}

		private void btnClear_Click(object sender, System.EventArgs e)
		{
			clickedOperator="";
			Value=0;
			startedNew=true;
		}
		public void Show(string clickedOperator)
		{
			if(("+-*/").IndexOf(clickedOperator)>=0&&clickedOperator.Length==1)
			{
				startedNew=true;
				firstValue=Value;
				this.clickedOperator=clickedOperator;
			}
			this.Show();			
		}
		private void btnBack_Click(object sender, System.EventArgs e)
		{
			if(NumberKeyPressed!=null)
				NumberKeyPressed(this,new KeyPressEventArgs(Convert.ToChar(8)));
		}

		private void btnEqual_Click(object sender, System.EventArgs e)
		{
			PerformOperation();
			clickedOperator="";
			startedNew=false;
			firstValue=0;
			this.Hide();
		}
		private double calcValue=0;

		private void frmCalculator_Load(object sender, System.EventArgs e)
		{
			previousValue=Value;
		}
	
		public double Value
		{
			get
			{
				return calcValue;
			}
			set
			{
				if(calcValue!=value&&ValueChanged!=null)
					ValueChanged(this,value);
				calcValue=value;
			}
		}
		protected override void OnPaint(PaintEventArgs e)
		{
			base.OnPaint (e);
			System.Drawing.Pen pen=new System.Drawing.Pen(System.Drawing.Color.Gray,1);
			e.Graphics.DrawRectangle(pen,2,2,this.Width-4,this.Height-4);
			e.Graphics.DrawLine(pen,2,10,this.Width-3,10);
		}
	}
}