How to authenticate the password in an email application built on windows forms?

Question

Yesterday, i had a task assigned by my senior to build a windows forms application in .net which looked like the image i attached. I did all the stuff regarding the sending process of the email application, but i stuck at one place, i couldn't figure out how to authenticate the password in the email form. The password must be of the same email, which was provided in the "From :" fields. This image displays the form which i designed

Here is the code behind of my form,

 public partial class Form1 : Form
{
    MailMessage message;
    SmtpClient smtp;
    public Form1()
    {

        InitializeComponent();
        lbl_Error.Visible = false;
    }

    private void chk_Show_Password_CheckedChanged(object sender, EventArgs e)
    {

        if (chk_Show_Password.Checked == true)
            txt_Password.PasswordChar= '\0';
        else
            txt_Password.PasswordChar='*';



    }

    private void btn_Send_Click(object sender, EventArgs e)
    {
        btn_Send.Enabled = false;
        txt_Password.Text = "";


        try
        {
            message = new MailMessage();
            if(isValidEmail(txt_From.Text))
            {
                message.From = new MailAddress(txt_From.Text);
            }

            if (isValidEmail(txt_To.Text))
            {
                message.To.Add(txt_To.Text);
            }

            message.Body = txt_Details.Text;

            //attributes for smtp
            smtp = new SmtpClient("smtp.gmail.com");
            smtp.Port = 587;
            smtp.EnableSsl = true;
            smtp.UseDefaultCredentials = false;
            smtp.Credentials = new NetworkCredential("imad.majid90@gmail.com", "mypassword");
            smtp.Send(message);

        }

        catch(Exception ex)
        {
            btn_Send.Enabled = true;
            MessageBox.Show(ex.Message);

        }
    }

    public bool isValidEmail(string email)
    {
        bool flagFalse = false; ;
        if (!email.Contains('@'))
        {
            lbl_Error.Visible = true;
            lbl_Error.ForeColor = System.Drawing.Color.Red;
            lbl_Error.Text = "Email address must contain @";
            return flagFalse;
        }

        return true;
    }

}

I'm not sure I understand... you need to verify that the password is correct for the email it is sending from? Why not just try and send the email and catch an Exception if it fails? — jebar8, Mar 07 '13 at 05:05
and then i would add another label on the design, and in the code behind file, i would catch the error and display it in the label. Thats what you are advising me? -@jebar8 — codeLearner, Mar 07 '13 at 05:08
Thanks for your answer, and i realized the mistake, in the password credentials, i must take the value in the password textbox, rather than hard coding the password. thanks a lot jebar :-) — codeLearner, Mar 07 '13 at 05:31

jebar8 · Accepted Answer · 2013-03-07T05:20:07.983

Assuming you're using Gmail like the screenshot you posted shows, you can't check the password without trying to send the email.

My advice would be to attempt to send the email and catch an Exception if it fails. You can then show some indication that there has been an error, like a MessageBox or a Label on your form.

See the documentation for SmtpClient. The Send methods will throw an SmtpException if authentication fails.

EDIT:

Well, after seeing the additional code you posted, you are already handling any exceptions that are thrown, including an authentication failure. The user will see a MessageBox if the password is incorrect.

score 0 · Answer 2 · edited May 23 '17 at 10:27

0

Do a try catch for SmtpException and display the information to the user is unauthenticated.

http://msdn.microsoft.com/en-us/library/h1s04he7.aspx

It looks like your using Windows Authentication. It might be easier to fetch the user's email from Active Directory rather then prompting for credentials.

How to obtain email address with window authentication

edited May 23 '17 at 10:27

Community

1
1

answered Mar 07 '13 at 05:21

Kye

5,919
10
49
84

Thanks a lot Kye, i got the solution now, and realized my stupid mistake :-) – codeLearner Mar 07 '13 at 05:32

score 0 · Answer 3 · answered Mar 07 '13 at 05:43

0

 catch(Exception ex)
    {
        btn_Send.Enabled = true;
       // MessageBox.Show(ex.Message);
         lbl_Error.Text = "Invalid Username/Password";

    }

answered Mar 07 '13 at 05:43

Manoj Kumar Yellapragada

132
1
11

How to authenticate the password in an email application built on windows forms?

3 Answers3