C# Winforms Log-In Form using Binary File

Question

I am currently working on a school project that will have your classic log-in/register form. The project requires that we include a binary file to 'securely' store each User's information e.g username, password etc.

I am successfully writing new user's information to a binary file named "users" when they register, and then I am successfully reading it back to a rich text box. (This is simply so I know that everything is being read back).

I am also able to successfully recognise the last registered user when this user is inputted to the Log-In section of the form, but I cannot recognise any other user's information.

My code for the Register (e.g when the registry button is clicked)

private void btnRegister_Click(object sender, EventArgs e)
{
    //Try - Catch Statements
    //Try to set the forename

    try
    {
        newUser.Forename = txtForename.Text;
        errForename.Icon = Properties.Resources.CorrectIcon;
        errForename.SetError(txtForename, "OK");
    }

    // catch the exception error if one is raised and place the message
    //into the ErrorProvider

    catch (NewException exc)
    {
        errForename.SetError(txtForename, exc.MessageM);
    }

    //Try to set the surname
    try
    {
        newUser.Surname = txtSurname.Text;
        errSurname.Icon = Properties.Resources.CorrectIcon;
        errSurname.SetError(txtSurname, "OK");
    }

    // catch the exception error if one is raised and place the message
    //into the ErrorProvider

    catch (NewException exc)
    {
        errSurname.SetError(txtSurname, exc.MessageM);
    }

    //Try to set the password
    try
    {
        newUser.Password = txtPasswordR.Text;
        errPasswordR.Icon = Properties.Resources.CorrectIcon;
        errPasswordR.SetError(txtPasswordR, "OK");
    }

    // catch the exception error if one is raised and place the message
    //into the ErrorProvider

    catch (NewException exc)
    {
        errPasswordR.SetError(txtPasswordR, exc.MessageM);
    }    

    // These lines of code set the User class 

    if (newUser.Password != null )
    { 
        newUser.Forename = txtForename.Text;
        newUser.Surname = txtSurname.Text;
        newUser.Username = txtUsernameR.Text;
        newUser.Password = txtPasswordR.Text;   

        FileStream fileStream = new FileStream("../../Textfiles/users.bin", FileMode.Append);
        BinaryWriter binaryWriter = new BinaryWriter(fileStream);
        {
            binaryWriter.Write(newUser.Forename);
            binaryWriter.Write(newUser.Surname);
            binaryWriter.Write(newUser.Username);
            binaryWriter.Write(newUser.Password);

        }

        binaryWriter.Flush();
        binaryWriter.Close();
    }
}

My Code for Reading from the Bin file

public bool ReadFromBin(string a, string b)
{
    bool okFlag = false;

    FileStream fileStream = File.OpenRead("../../TextFiles/users.bin");
    BinaryReader binaryReader = new BinaryReader(fileStream);

    while (binaryReader.PeekChar() != -1)
    {
        newUser.Forename = binaryReader.ReadString();
        newUser.Surname = binaryReader.ReadString();
        newUser.Username = binaryReader.ReadString();
        newUser.Password = binaryReader.ReadString();


        if ((newUser.Username == a) && (newUser.Password == b))
            okFlag = true;
        else
            okFlag = false;
    }

    binaryReader.Close();
    return okFlag;
}

And finally the very simple code for the Log-in

private void btnLogIn_Click(object sender, EventArgs e)
{
    if(this.ReadFromBin(txtUsername.Text, txtPassword.Text) == false)
    {
        MessageBox.Show("Not registered!");
    }
    else
    {
        MessageBox.Show("Registered!");
        Game frm = new Game(newUser);
        frm.Show();
    }
}

My understanding is that the problem is most likely in the while loop contained within the ReadFromBin method, I am just unsure of how to fix it. Thanks!

Answer 1

I believe you're problem is in the condition.

You are always testing if the user is (a,b) and only if the last user is (a,b) your code will work.

You need to change the following:

public bool ReadFromBin(string a, string b)
    {
        bool okFlag = false;

        FileStream fileStream = File.OpenRead("../../TextFiles/users.bin");
        BinaryReader binaryReader = new BinaryReader(fileStream);

        while (binaryReader.PeekChar() != -1)
        {
            newUser.Forename = binaryReader.ReadString();
            newUser.Surname = binaryReader.ReadString();
            newUser.Username = binaryReader.ReadString();
            newUser.Password = binaryReader.ReadString();


            if ((newUser.Username == a) && (newUser.Password == b))
              {
                 okFlag = true;
                 break;
              }
        }

        binaryReader.Close();
        return okFlag;


    }