gui.cs

This code is a cipher which takes in a plaintext or ciphertext string and encrypts / decrypts accord

			this.groupBox2.ResumeLayout(false);
			this.ResumeLayout(false);

		}
		#endregion

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

		private void Form1_Load(object sender, System.EventArgs e)
		{
			
			this.plaintext.Enabled = true;
			this.ciphertext.Enabled = false;
			this.plaintext.Focus();
			this.encryptbutton.Enabled = true;
			this.decryptbutton.Enabled = false;
		
		
		}


		private void plainButton_CheckedChanged(object sender, System.EventArgs e)
		{
			this.ciphertext.Enabled = false;	//disabled field
			this.encryptbutton.Enabled = true;  //enabled field
			this.decryptbutton.Enabled = false; //disabled field
			this.plaintext.Enabled = true;		//disabled field
			//changes text in accordance with encryption method selection
			this.label1.Text = "Please enter the value to encrypt by:";
			this.plaintext.Focus();				//set focus
			this.IncValue.Clear();				//clear the value
			
			
		}

		private void cipherButton_CheckedChanged(object sender, System.EventArgs e)
		{	
			this.plaintext.Enabled = false;		//disabled field
			this.ciphertext.Enabled = true;		//enabled field
			this.encryptbutton.Enabled = false;	//disabled field
			this.decryptbutton.Enabled = true;	//enabled field
			//changes text in accordance with decryption method selection
			this.label1.Text = "Please enter the value to decrypt by:";
			this.ciphertext.Focus();			//set the focus
			this.IncValue.Clear();				//clear the field
		}

		private void decryptbutton_Click(object sender, System.EventArgs e)
		{
			//the following code opens up the file ErrorLog.txt and writes the error
			//details to this file for further information			
			StreamWriter sr = File.AppendText(FILE_NAME);
			
			Decryption decrypt = new Decryption();// create new instance of class Decryption
			Unicode unicode = new Unicode();      // create new insatnce of class Unicode
			string temp = "";

			if(this.ciphertext.Text == "") //if no text entered give error message
			{
				MessageBox.Show("Cannot Decrypt - no cyphertext entered!");
				this.ciphertext.Focus();	//set key focus to ciphertext field
				
			}	
			else 
				try	//try block for the decryption fucntion
				{//pass in the text and increment value and return temp
					temp = decrypt.Decrypt(this.ciphertext.Text, this.IncValue.Text);
					this.plaintext.Text = temp; //display text in temp
					
				}
				//Catch Method 1: catch the Format and OverflowException in the one catch
				//and sort into types
				catch(Exception excep)//catch all exceptions
				{
					//get the type of exception and converts it to a string
					string type = excep.GetType().ToString();
					string desc = excep.ToString(); 
					//if the num entered is not a number or nothing is entered
					if(type == "System.FormatException")
					{
						MessageBox.Show("Please Enter in a value by which to Decrypt by", "Error");
						this.IncValue.Focus();//set focus to IncValue field
						this.IncValue.Clear();//clear the field
						

					}
					//if too many integers are entered into the field
					else if(type == "System.OverflowException")
					{
						MessageBox.Show("Number to large to encrypt, please enter in another number", "Error");
						this.IncValue.Focus();//set focus to IncValue field
						this.IncValue.Clear();//clear the field
						
					}
					else
					{
						
						MessageBox.Show("Unexpected Exception - See ErrorLog.txt for further information" ,"Error");
					
					}
					//write all the error details to  a log file called errorlog.txt,
					// user can read the file and view descriptions
					sr.WriteLine("The following is a detailed description of the error\n" + desc);
					
			}			
			sr.Close(); // close the file
		}

		private void encryptbutton_Click(object sender, System.EventArgs e)
		{
			//opens up the file ErrorLog.txt and writes the error
			//details to this file for further information		
			StreamWriter sr = File.AppendText(FILE_NAME);
			
			Encryption encrypt = new Encryption();	// create new instance of class Encryption
			Unicode unicode = new Unicode();		// create new instance of class Encryption
			string temp = "";						// initialise temp string to null 
			if(this.plaintext.Text == "")
			{
				MessageBox.Show("Cannot Encrypt - No Plaintext entered");
				this.plaintext.Focus();				//set cursor to plaintext 
			}	
				else 
				try//try block for the decryption fucntion
				{//pass in the text and increment value and return temp
					temp = encrypt.Encrypt(this.plaintext.Text, this.IncValue.Text);
					ciphertext.Text = temp;	//display text in ciphertext field
				}
			
				//Catch Method 2 catch the Format and OverflowException seperately
				catch(FormatException fexcept)
				{
					MessageBox.Show("Please enter in a numeric value by which to Encrypt by", "Error");
					string tempex = fexcept.ToString();		//sets tempex to string of fexecpt variable
					this.IncValue.Clear();					//clears the field
					this.IncValue.Focus();					//sets focus on the field
					//The following line writes out the error to the text file ErrorLog.txt
					sr.WriteLine("The following is a detailed description of the error\n" + tempex);
				}
		
				catch(OverflowException overex)
				{
					MessageBox.Show("Number to large to encrypt, please enter in another number", "Error");
					string tempex = overex.ToString();	//sets tempex to string of overex variable
					this.IncValue.Clear();				//clears field
					this.IncValue.Focus();				//sets focus
					//print out error file
					sr.WriteLine("The following is a detailed description of the error\n" + tempex);
				}
			
			sr.Close();//close the file
		}
	

	

		//The following function performs as a key listener and only permits numeric entry
		private void IncValue_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs ke)
		{
			bool flag;
			//call to function isHandled to determine whether the key pressed is valid or not
			flag = isHandled(this.IncValue.Text,ke);
			//gets return value and if true then handle the event
			//i.e do not let text be inputted into the text area
			//if false permit
			if(flag == true)
			{
				ke.Handled = true;
			}

			
		}
		private bool isHandled(object sender, System.Windows.Forms.KeyPressEventArgs ke)
		{
			int numkey = 0;
			numkey = (int)ke.KeyChar;//gets the character corresponding to the key pressed
			bool flag;
			//if the character is less than 48 or greater than 57 or not a backspace in ascii
			if((numkey < 48 || numkey > 57) && (numkey != 8))		
				//(48ascii = 0 in dec and 57ascii = 9 in dec)
			{	
				flag = true;	//return true digits 0 - 9, backspace
				return flag;			// return the flag
			}
				else 
				{
					flag = false;			// else set the flag to false
					return flag;			//return the flag
				}
		}

		private void Clear_Click(object sender, System.EventArgs e)
		{
				this.plaintext.Clear();			//clear the plaintext field
				this.ciphertext.Clear();		//clear the ciphertext field
				this.IncValue.Clear();			//clear the value field
			
		}
		private void Quit_Click(object sender, System.EventArgs e)
		{
			Application.Exit();//exit the application
		}
		//following code displays text after the mouse has been placed over the plaintext textfield
		private void plaintext_MouseHover(object sender, System.EventArgs e)
		{
			toolTip1.SetToolTip(this.plaintext, "Enter your plaintext \nto encrypt here");
		}

		//following code displays text after the mouse has been placed over the ciphertext textfield
		private void ciphertext_MouseHover(object sender, System.EventArgs e)
		{
			toolTip2.SetToolTip(this.ciphertext, "Enter your ciphertext \nto decrypt here");
		}
		//following code displays text after the mouse has been placed over the encrypt button
		private void encryptbutton_MouseHover(object sender, System.EventArgs e)
		{
			toolTip3.SetToolTip(this.encryptbutton, "Encrypts plaintext to cyphertext");
		}
		//following code displays text after the mouse has been placed over the decrypt button
		private void decryptbutton_MouseHover(object sender, System.EventArgs e)
		{
			toolTip4.SetToolTip(this.decryptbutton, "Decrypts from cyphertext to plaintext");
		}
		//following code displays text after the mouse has been placed over the clear button
		private void Clear_MouseHover(object sender, System.EventArgs e)
		{
			toolTip5.SetToolTip(this.Clear, "Clears all text fields");
		}
		//following code displays text after the mouse has been placed over the plaintext textfield
		private void Quit_MouseHover(object sender, System.EventArgs e)
		{
			toolTip6.SetToolTip(this.Quit, "Quits the application");
		}


		


		

		
		

		

		

		
		

		

	
	}
}