/// <summary>
/// Spawns a new thread for TCP communication.
/// </summary>
private void StartServer()
{
try
{
th = new Thread(new ThreadStart(StartListen));
th.Start();
}
catch (Exception ex)
{
MyMessageBox.ShowMessage("Failed to start the server: " + ex.ToString());
}
}
//The public key must be send to the client so they can
//encrypt their symmetric key and send it back without the key being compromised
private void SendPublicKey()
{
byte[] bt;
bt = Encoding.UTF8.GetBytes(GetPublicKeyString());
try
{
connectedClient.Client.Send(bt);
}
catch (Exception ex)
{
MyMessageBox.ShowMessage("Failed to send RSA public key: " + ex.ToString());
}
}
/// <summary>
/// Retrieves the relevant records from TblStaff in the
/// database and stores them in the staffMembers list.
/// </summary>
private void InitaliseList()
{
try
{
SqlConnector db = new SqlConnector();
staffMembers = db.GetStaff_All();
}
catch
{
MyMessageBox.ShowMessage("Access to the database failed.");
return;
}
UpdateStaffMemberList();
}
private void ButtonSearch_Click(object sender, EventArgs e)
{
try
{
SqlConnector db = new SqlConnector();
students = db.GetStudentList_BySearch(TextBoxSearchBar.Text);
}
catch
{
MyMessageBox.ShowMessage("Access to database failed.");
return;
}
UpdateStudentList();
}
private void ButtonAddNotes_Click(object sender, EventArgs e)
{
//If no student is selected, then display a message.
//Otherwise, open a new AddNoteForm.
if (ListBoxStudentList.SelectedItem == null)
{
MyMessageBox.ShowMessage("No student selected.");
}
else
{
AddNoteForm addNoteForm = new AddNoteForm(selectedStudent);
addNoteForm.ShowDialog();
}
}
//Staff name must be sent before the client and server begin chatting,
//so the users know who they're communicating with
private void SendStaffName()
{
string encryptedMessage = ClassLibrary.SymmetricEncryptDecrypt(staffMember.StaffFirstName, symmetricKey);
byte[] bt = Encoding.UTF8.GetBytes(encryptedMessage);
try
{
connectedClient.Client.Send(bt);
}
catch (Exception ex)
{
MyMessageBox.ShowMessage("Failed to send staff first name: " + ex.ToString());
}
}
/// <summary>
/// When a new item is selected in ListBoxNoteList,
/// that note is to be displayed in TextBoxNoteViewer.
/// </summary>
private void UpdateNoteViewer()
{
try
{
SqlConnector db = new SqlConnector();
notes = db.GetNote_ByNoteID(snl[ListBoxNoteList.SelectedIndex].NoteID);
}
catch
{
MyMessageBox.ShowMessage("Failed to load notes from the database.");
return;
}
TextBoxNoteViewer.Text = notes[0].NoteContents;
}
private void ButtonSearch_Click(object sender, EventArgs e)
{
try
{
//Updates the list of students according to what was input in the search box
SqlConnector db = new SqlConnector();
students = db.GetStudentList_BySearch(TextBoxSearchBar.Text);
}
catch
{
MyMessageBox.ShowMessage("Failed to load student list from the database.");
return;
}
UpdateStudentList();
}
/// <summary>
/// Retrieves the relevant records from TblMeeting in the database and
/// stores them in the meetings list.
/// The ListBoxUpcomingMeetings is then populated using the meetings list.
/// </summary>
public void InitaliseList()
{
try
{
SqlConnector db = new SqlConnector();
meetings = db.GetMeeting_ByStaffIDAndDate(staffMember.StaffID, DateTime.Now.Date);
}
catch
{
MyMessageBox.ShowMessage("Failed to load meetings from the database.");
return;
}
ListBoxUpcomingMeetings.DataSource = meetings;
ListBoxUpcomingMeetings.DisplayMember = "StaffPOVUpcomingAppointment";
}
/// <summary>
/// Retrieves the relevant records from TblStudent in the
/// database and stores them in the students list.
/// </summary>
private void InitaliseList()
{
try
{
SqlConnector db = new SqlConnector();
students = db.GetStudent_All();
}
catch
{
MyMessageBox.ShowMessage("Access to database failed.");
return;
}
UpdateStudentList();
}
/// <summary>
/// Retrieves the relevant records from TblMeeting in the database and
/// stores them in the meetings list.
/// The ListBoxUpcomingMeetings is then populated using the meetings list.
/// </summary>
private void InitaliseList()
{
//If access to the database fails, display a message to the user.
try
{
SqlConnector db = new SqlConnector();
meetings = db.GetMeeting_ByStudentIDAndDate(student.StudentID, DateTime.Now.Date);
}
catch
{
MyMessageBox.ShowMessage("Failed to load meetings from the database.");
return;
}
ListBoxUpcomingMeetings.DataSource = meetings;
ListBoxUpcomingMeetings.DisplayMember = "StudentPOVUpcomingAppointment";
}
/// <summary>
/// Function to stop the server.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void ButtonStopServer_Click(object sender, EventArgs e)
{
try
{
StopServer();
}
catch (Exception ex)
{
MyMessageBox.ShowMessage("Failed to stop the server: " + ex.ToString());
return;
}
//Set the controls to show the server is offline
TextBoxServerStatus.BackColor = Color.Red;
ButtonStartServer.Enabled = true;
ButtonStopServer.Enabled = false;
}
/// <summary>
/// When a new item is selected in ListBoxMessageList,
/// that message is to be displayed in TextBoxMessageViewer
/// </summary>
private void UpdateMessageViewer()
{
try
{
SqlConnector db = new SqlConnector();
messages = db.GetMessage_ByMessageID(sml[ListBoxMessageList.SelectedIndex].MessageID);
}
catch
{
MyMessageBox.ShowMessage("Failed to load message from the database.");
return;
}
TextBoxMessageViewer.Text = messages[0].MessageContents;
TextBoxDate.Text = messages[0].MessageDate.ToString().Substring(0, 10);
TextBoxTime.Text = messages[0].MessageTime.ToString().Substring(0, 5);
}
public void UpdateList()
{
try
{
SqlConnector db = new SqlConnector();
oldMeetings = db.GetOldMeeting_ByStaffIDAndDate(staffMember.StaffID, DateTime.Now.Date);
}
catch
{
MyMessageBox.ShowMessage("Failed to load meetings from the database.");
return;
}
ListBoxOldMeetings.DataSource = oldMeetings;
ListBoxOldMeetings.DisplayMember = "StaffPOVOldAppointment";
TextBoxCounter.Text = oldMeetings.Count.ToString();
}
private void ButtonStartServer_Click(object sender, EventArgs e)
{
try
{
StartServer();
}
catch (Exception ex)
{
MyMessageBox.ShowMessage(ex.ToString());
return;
}
//Set the controls to show the server is operational
TextBoxServerStatus.BackColor = Color.Green;
ButtonStartServer.Enabled = false;
ButtonStopServer.Enabled = true;
TreeViewClientList.Enabled = true;
}
private void ButtonUpdatePassword_Click(object sender, EventArgs e)
{
//If the input data is valid
if (ValidateForm())
{ //If the current password is correct
if (student.StudentPassword == TextBoxOldPassword.Text)
{
//If the 2 new passwords match each other
if (TextBoxNewPassword.Text == TextBoxReTypePassword.Text)
{
try
{
SqlConnector db = new SqlConnector();
db.UpdateStudentPassword(student.StudentID, TextBoxReTypePassword.Text);
}
catch
{
MyMessageBox.ShowMessage("Action aborted. Access to database failed.");
ClearAllFields();
return;
}
student.StudentPassword = TextBoxReTypePassword.Text;
MyMessageBox.ShowMessage("Password successfully changed.");
ClearAllFields();
}
else
{
MyMessageBox.ShowMessage("New passwords do not match. Check your spelling and try again.");
ClearAllFields();
}
}
else
{
MyMessageBox.ShowMessage("Incorrect password input.");
ClearAllFields();
}
}
else
{
MyMessageBox.ShowMessage("Not all components validated successfully.");
ClearAllFields();
}
}
private void ButtonDeleteMeeting_Click(object sender, EventArgs e)
{
if (meetings.Count() == 0 || ListBoxUpcomingMeetings.SelectedItem == null)
{
MyMessageBox.ShowMessage("No meetings to delete.");
}
else
{
MeetingModel meeting = meetings[ListBoxUpcomingMeetings.SelectedIndex];
string studentID = meeting.StudentID;
int staffID = meeting.StaffID;
List <StudentModel> studentToEmail;
try
{
SqlConnector db = new SqlConnector();
db.DeleteMeeting_ByMeetingID(meeting.MeetingID);
}
catch
{
MyMessageBox.ShowMessage("Action aborted. Access to database failed.");
return;
}
InitaliseList();
//Find participating student
try
{
SqlConnector db = new SqlConnector();
studentToEmail = db.GetStudent_ByStudentID(studentID);
}
catch
{
MyMessageBox.ShowMessage("Action aborted. Access to database failed.");
return;
}
//Email the participants
SendEmail_CancelMeeting(studentToEmail[0].StudentEmail, staffMember.StaffFirstName, staffMember.StaffLastName, meeting);
SendEmail_CancelMeeting(staffMember.StaffEmail, studentToEmail[0].StudentFirstName, studentToEmail[0].StudentLastName, meeting);
}
}
private void ButtonUpdatePassword_Click(object sender, EventArgs e)
{
//If the user input data validates correctly
if (ValidateForm())
{
if (staffMember.StaffPassword == TextBoxOldPassword.Text)
{
if (TextBoxNewPassword.Text == TextBoxReTypePassword.Text)
{
try
{
SqlConnector db = new SqlConnector();
db.UpdateStaffPassword(staffMember.StaffID, TextBoxReTypePassword.Text);
}
catch
{
MyMessageBox.ShowMessage("Action aborted. Access to database failed.");
return;
}
staffMember.StaffPassword = TextBoxReTypePassword.Text;
ClearAllFields();
MyMessageBox.ShowMessage("Password successfully changed.");
}
else
{
MyMessageBox.ShowMessage("New passwords do not match. Check your spelling and try again.");
ClearAllFields();
}
}
else
{
MyMessageBox.ShowMessage("The password you entered was incorrect.");
ClearAllFields();
}
}
else
{
MyMessageBox.ShowMessage("Not all components validated successfully.");
ClearAllFields();
}
}
private void ButtonAddNote_Click(object sender, EventArgs e)
{
//If the TextBoxAddNote contains valid data
if (ValidateForm_AddNote())
{
NoteModel n = new NoteModel(TextBoxNote.Text);
try
{
//Add the note to the database
GlobalConfig.Connection.CreateNote(n, student.StudentID);
}
catch
{
MyMessageBox.ShowMessage("Failed to add note.");
return;
}
MyMessageBox.ShowMessage($"Note successfully added to {student.StudentFirstName} {student.StudentLastName}.");
TextBoxNote.Text = "";
}
}
private void ButtonPinMessage_Click(object sender, EventArgs e)
{
if (ListBoxChat.SelectedItem != null)
{
MessageModel m = new MessageModel(ListBoxChat.SelectedItem.ToString(), DateTime.Now, DateTime.Now);
try
{
GlobalConfig.Connection.CreateMessage(m, connectedStudent.StudentID);
MyMessageBox.ShowMessage($"Message successfully pinned to {connectedStudent.StudentFirstName} {connectedStudent.StudentLastName}.");
}
catch
{
MyMessageBox.ShowMessage("Failed to pin message.");
}
}
else
{
MyMessageBox.ShowMessage("Error: no message selected. Please select a message and try again.");
}
}
// If there are no pinned messages left to delete,
//display a message saying so
private void ButtonDeleteMessage_Click(object sender, EventArgs e)
{
if (sml.Count() == 0 || ListBoxMessageList.SelectedItem == null)
{
MyMessageBox.ShowMessage("No messages to delete.");
}
else
{
try
{
SqlConnector db = new SqlConnector();
db.DeleteMessage_ByMessageID(sml[ListBoxMessageList.SelectedIndex].MessageID);
}
catch
{
MessageBox.Show("Action aborted. Access to database failed.");
return;
}
InitaliseList();
}
}
private void ButtonDeleteStudent_Click(object sender, EventArgs e)
{
if (ListBoxStudentList.SelectedItem == null)
{
MyMessageBox.ShowMessage("No students to delete.");
}
else
{
try
{
SqlConnector db = new SqlConnector();
db.DeleteStudent_ByStudentID(students[ListBoxStudentList.SelectedIndex].StudentID);
}
catch
{
MyMessageBox.ShowMessage("Action aborted: attempted to delete a student present in multiple tables.");
return;
}
InitaliseList();
}
}
private void ButtonClearOldMeetings_Click(object sender, EventArgs e)
{
if (oldMeetings.Count > 0)
{
try
{
SqlConnector db = new SqlConnector();
db.DeleteExpiredMeetings();
}
catch
{
MyMessageBox.ShowMessage("Action aborted. Access to database failed.");
return;
}
UpdateList();
MyMessageBox.ShowMessage("Expired meetings successfully cleared.");
}
else
{
MyMessageBox.ShowMessage("No meetings to delete.");
}
}
private void ButtonDeleteNote_Click(object sender, EventArgs e)
{
//If there are no notes to delete, display a message saying so
if (snl.Count() == 0 || ListBoxNoteList.SelectedItem == null)
{
MyMessageBox.ShowMessage("No notes to delete.");
}
else
{
try
{
SqlConnector db = new SqlConnector();
db.DeleteNote_ByNoteID(snl[ListBoxNoteList.SelectedIndex].NoteID);
}
catch
{
MessageBox.Show("Action aborted. Access to database failed.");
return;
}
InitaliseList();
}
}
private void ButtonAddStudent_Click(object sender, EventArgs e)
{
const string REPEATSTUDENTIDERROR = "Student ID is already present in the database";
if (ValidateForm())
{
StudentModel model = new StudentModel(
TextBoxStudentIDValue.Text,
TextBoxFirstNameValue.Text,
TextBoxLastNameValue.Text,
TextBoxStudentIDValue.Text);
try
{
GlobalConfig.Connection.CreateStudent(model);
}
catch (SqlException)
{
MyMessageBox.ShowMessage("Failed to add student to the database: the specified student ID is already present in the database.");
ErrorProvider.SetError(TextBoxStudentIDValue, REPEATSTUDENTIDERROR);
return;
}
catch
{
MyMessageBox.ShowMessage("Failed to access the database. ");
return;
}
MyMessageBox.ShowMessage("Successfully added new student to the database.");
TextBoxStudentIDValue.Clear();
TextBoxFirstNameValue.Clear();
TextBoxLastNameValue.Clear();
SendEmail_AddStudent(model);
}
else
{
MyMessageBox.ShowMessage("Not all components validated successfully. Please check the flagged entries and try again.");
}
}
/// <summary>
/// Callback function called when data is received on the socket
/// </summary>
/// <param name="ar"></param>
public void OnReceive(IAsyncResult ar)
{
string content = string.Empty;
int bytesRead;
// Retrieve the state object and the handler socket
//from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket clientSocket = state.workSocket;
if (clientSocket.Connected)
{
// Read data from the client socket.
try
{
bytesRead = clientSocket.EndReceive(ar);
if (bytesRead > 0)
{
if (!symmetricKeyReceived)
{
byte[] temp = state.buffer;
int i = temp.Length - 1;
while (temp[i] == 0)
{
--i;
}
// now data[i] is the last non-zero byte
byte[] receivedData = new byte[i + 1];
Array.Copy(temp, receivedData, i + 1);
//Get the symmetric key after decrypting it using RSA
byte[] decryptedKey = rsa.Decrypt(receivedData, false);
string decryptedKeyString = Convert.ToBase64String(decryptedKey);
symmetricKey = decryptedKeyString;
symmetricKeyReceived = true;
SendStaffName();
clientSocket.BeginReceive(state.buffer, 0, StateObject.BufferSize,
0, new AsyncCallback(OnReceive), state);
return;
}
// There might be more data, so store the data received so far.
state.sb.Remove(0, state.sb.Length);
state.sb.Append(Encoding.UTF8.GetString(state.buffer, 0, bytesRead));
if (!studentNameReceived)
{
string encryptedStudentID = state.sb.ToString();
string sID = ClassLibrary.SymmetricEncryptDecrypt(encryptedStudentID, symmetricKey);
try
{
SqlConnector db = new SqlConnector();
List <StudentModel> listStudents = db.GetStudent_ByStudentID(sID);
connectedStudent = listStudents[0];
}
catch
{
MyMessageBox.ShowMessage("Access to the database failed.");
return;
}
SetTextBoxStudentName();
studentNameReceived = true;
clientSocket.BeginReceive(state.buffer, 0, StateObject.BufferSize,
0, new AsyncCallback(OnReceive), state);
return;
}
// Display text in rich text box
string received = state.sb.ToString();
content = ClassLibrary.SymmetricEncryptDecrypt(received, symmetricKey);
SetText(content);
clientSocket.BeginReceive(state.buffer, 0, StateObject.BufferSize,
0, new AsyncCallback(OnReceive), state);
}
else
{
//Disconnect request has 0 bytes.
//So if 0 byte message detected: disable further communication.
SetSendButton(false);
SetTextBoxConnectionStatus(Color.Red);
clientStream.Dispose();
clientStream.Close();
connectedClient.Client.Dispose();
connectedClient.Client.Close();
}
}
catch (SocketException socketException)
{
//WSAECONNRESET, the other side closed impolitely
if (socketException.ErrorCode == 10054 || ((socketException.ErrorCode != 10004) && (socketException.ErrorCode != 10053)))
{
// Complete the disconnect request.
string remoteIP =
((IPEndPoint)clientSocket.RemoteEndPoint).Address.ToString();
string remotePort =
((IPEndPoint)clientSocket.RemoteEndPoint).Port.ToString();
this.ownerForm.DisconnectClient(remoteIP, remotePort);
clientSocket.Close();
clientSocket = null;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
}
}
}
private void ButtonSendEmail_Click(object sender, EventArgs e)
{
ClassLibrary.CheckEmailIsValid(TextBoxEmail, ErrorProvider);
//If the ErrorProvider has an error set, then display a message
if (ErrorProvider.GetError(TextBoxEmail) != "")
{
MyMessageBox.ShowMessage("Not all components validated successfully. Please check the flagged entries and try again.");
return;
}
else if (RadioButtonStudent.Checked == true)
{
List <StudentModel> students = new List <StudentModel>();
try
{
SqlConnector db = new SqlConnector();
students = db.GetStudent_All();
}
catch
{
MyMessageBox.ShowMessage("Access to database failed.");
return;
}
//Search each StudentModel in the student list.
//If the email the user input matches an email in the
//database, send the email.
for (int i = 0; i < students.Count; i++)
{
if (students[i].StudentEmail == TextBoxEmail.Text)
{
ErrorProvider.SetError(TextBoxEmail, null);
//Send email
SendEmail(students[i].StudentEmail, students[i].StudentFirstName, students[i].StudentID, students[i].StudentPassword);
MyMessageBox.ShowMessage("Email successfully sent.");
return;
}
}
}
else if (RadioButtonStaff.Checked)
{
List <StaffModel> staffMembers = new List <StaffModel>();
try
{
SqlConnector db = new SqlConnector();
staffMembers = db.GetStaff_All();
}
catch
{
MyMessageBox.ShowMessage("Access to database failed.");
return;
}
for (int i = 0; i < staffMembers.Count; i++)
{
if (staffMembers[i].StaffEmail == TextBoxEmail.Text)
{
ErrorProvider.SetError(TextBoxEmail, null);
//Send email
SendEmail(staffMembers[i].StaffEmail, staffMembers[i].StaffFirstName, staffMembers[i].StaffEmail, staffMembers[i].StaffPassword);
MyMessageBox.ShowMessage("Email successfully sent.");
return;
}
}
}
MyMessageBox.ShowMessage("This email doesn't exist in the database.");
}
private void ButtonCreateMeeting_Click(object sender, EventArgs e)
{
//If all the controls validated correctly
if (ValidateForm_CreateMeeting())
{
int meetingLength;
if (CheckBoxCustomLength.Checked)
{
meetingLength = int.Parse(TextBoxCustomLength.Text);
}
else
{
meetingLength = timeOptions[ListBoxMeetingLengths.SelectedIndex];
}
//Get the staff member selected in the listbox
StaffModel selectedStaffMember = staffMembers[ListBoxStaffList.SelectedIndex];
//Create a new meeting
MeetingModel meeting = new MeetingModel(
selectedStudent.StudentID,
DateTimePickerDate.Value,
DateTimePickerTime.Value,
meetingLength,
selectedStaffMember.StaffID);
try
{
GlobalConfig.Connection.CreateMeeting(meeting);
}
catch
{
MyMessageBox.ShowMessage("Failed to add meeting to the database.");
return;
}
MyMessageBox.ShowMessage("Successfully scheduled the meeting");
try
{
//Update the selected student's record in the database to show they have had a meeting before
SqlConnector db = new SqlConnector();
db.UpdateIsNewStudent(selectedStudent.StudentID);
}
catch
{
MyMessageBox.ShowMessage("Failed to update student's status.");
return;
}
TextBoxCustomLength.Clear();
//Email the participants
SendEmail_ScheduleMeeting(meeting, selectedStudent.StudentEmail, selectedStaffMember.StaffFirstName, selectedStaffMember.StaffLastName);
SendEmail_ScheduleMeeting(meeting, selectedStaffMember.StaffEmail, selectedStudent.StudentFirstName, selectedStudent.StudentLastName);
}
else
{
MyMessageBox.ShowMessage("Not all components validated successfully. Please check the flagged entries and try again.");
}
}
private void ButtonLogIn_Click(object sender, EventArgs e)
{
//True if all the components validate successfully
if (ValidateForm())
{
//Checks whether it is a student or staff member attempting to login
if (RadioButtonStudent.Checked == true)
{
List <StudentModel> studentLogInDetails = new List <StudentModel>();
try
{
//Attempt to retrieve the record from TblStudent in the database that exactly matches the data
//input to TextBoxUsername and TextBoxPassword.
SqlConnector db = new SqlConnector();
studentLogInDetails = db.GetStudent_ByLogInDetails(TextBoxUsername.Text, TextBoxPassword.Text);
}
catch
{
MyMessageBox.ShowMessage("Access to the database failed.");
return;
}
if (studentLogInDetails.Count() == 1)
{
this.Hide();
StudentMainForm studentMainForm = new StudentMainForm(studentLogInDetails[0]);
studentMainForm.ShowDialog();
this.Close();
}
else
{
MyMessageBox.ShowMessage("Check your username and password.");
}
}
else if (RadioButtonStaff.Checked == true)
{
List <StaffModel> staffLogInDetails = new List <StaffModel>();
try
{
SqlConnector db = new SqlConnector();
staffLogInDetails = db.GetStaff_ByLogInDetails(TextBoxUsername.Text, TextBoxPassword.Text);
}
catch
{
MyMessageBox.ShowMessage("Access to the database failed.");
return;
}
if (staffLogInDetails.Count() == 1)
{
this.Hide();
StaffMainForm staffMainForm = new StaffMainForm(staffLogInDetails[0]);
staffMainForm.ShowDialog();
this.Close();
}
else
{
MyMessageBox.ShowMessage("Check your username and password.");
}
}
}
else
{
MyMessageBox.ShowMessage("Not all components validated successfully. Please check the flagged entries and try again.");
}
}
/// <summary>
/// A callback function triggered when data is received on the socket.
/// </summary>
/// <param name="ar"></param>
public void OnReceive(IAsyncResult ar)
{
string content = string.Empty;
//Retrieve the state object and the handler socket from the asynchronous state object
state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
int bytesRead;
if (handler.Connected)
{
//Read data from the client socket
try
{
bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
//There might be more data, so store the data received so far
state.sb.Remove(0, state.sb.Length);
//Translate the bytes into a readable format
state.sb.Append(Encoding.UTF8.GetString(state.buffer, 0, bytesRead));
string s = state.sb.ToString();
//Before the server and client can begin chatting, the server must send its
//public key over, the client then sends a generated symmetric key back, encrypted
//using the public key. Then the server must send the staff member's name while
//the client must send the student ID.
if (!publicKeyReceived)
{
rsa = new RSACryptoServiceProvider(2048);
//Save the public key received to rsa
rsa.FromXmlString(state.sb.ToString());
SendSymmetricKey();
publicKeyReceived = true;
//Continue to asynchronously receive data from the server
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(OnReceive), state);
return;
}
if (!nameReceived)
{
SendStudentID();
string encryptedStaffName = state.sb.ToString();
staffName = ClassLibrary.SymmetricEncryptDecrypt(encryptedStaffName, symmetricKey);
nameReceived = true;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(OnReceive), state);
return;
}
//Display text in TextBox
string received = state.sb.ToString();
content = ClassLibrary.SymmetricEncryptDecrypt(received, symmetricKey);
//Function used to display text in the rich text box. A delegate function
//must be used as we're not on the main thread.
SetText(content);
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(OnReceive), state);
}
else
{
//If no data is received, then an error has occured as null messages cannot be sent.
MyMessageBox.ShowMessage("Error occured: no data was supplied.");
}
}
catch (SocketException socketEx)
{
//WSAECONNRESET: if the other side closes impolitely
//(they shut down the server or crash for some reason)
//Cut the connection and reset everything
if (socketEx.ErrorCode == 10054 || ((socketEx.ErrorCode != 10004) && (socketEx.ErrorCode != 10053)))
{
handler.Close();
SetTextBoxConnectionStatusBackgroundColour(Color.Red);
SetSendButton(false);
SetConnectButton(true);
SetDisconnectButton(false);
serverStream.Close();
server.Close();
nameReceived = false;
publicKeyReceived = false;
}
}
catch (Exception ex)
{
//Anyother unexpected error is displayed here
MyMessageBox.ShowMessage(ex.Message);
}
}
else
{
handler.Close();
}
}
