CODEWITHSUNDEEP
c#winforms
user1779026
user1779026

Reputation: 93

passing username to form but username returns null c#

This code is to return the value of textbox in the Login form.

public partial class Login : Form
{
    public string returnUsername()
    {
        string username = textBox1.Text;
        return username;
    }
}

This code is to allow the ChangePass form to show.

public partial class Mainmenu_Employee : Form
{
    private void changePasswd_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
    {
        this.Hide();
        Login login = new Login();
        ChangePass passwd = new ChangePass(login);
        passwd.Show();
    }
}

This code is to take the username from Login form so that I can change the password of the username.

    public partial class ChangePass : Form
    {
       Login login = null; //parent form
       Mainmenu_Employee main = new Mainmenu_Employee();


       public ChangePass(Login login1)
       {
           InitializeComponent();
           login = login1;
       }

       private void buttonChangePass_Click(object sender, EventArgs e)
       {

           Model_DB_Employee emp = new Model_DB_Employee();
           //Login login = new Login();
           string username = login.returnUsername();


           if (textBoxNewPass.Text == string.Empty || textBoxConfirmPass.Text == string.Empty)
           {
               MessageBox.Show("Field cannot be empty!");
           }
           else
           {
               if (textBoxNewPass.Text == textBoxConfirmPass.Text)
               {

                   try
                   {

                       emp.changePasswd(username,textBoxConfirmPass.Text);
                       MessageBox.Show(username);
                       MessageBox.Show("Password updated!");
                       this.Hide();
                       main.Show();
                   }
                   catch(SystemException ex)
                   {
                       MessageBox.Show("Password not updated" + ex);
                   }

               }
               else
               {
                   MessageBox.Show("Passwords do not match!");
               }
           }
       }

Change password function:

    public void changePasswd(string username, string newpass) //change password
    {
        Model_Employee emp = new Model_Employee();

        //Hasher hash = new Hasher(); //call hasher class for hashing
        //string hashed;
        //string salt = emp.generateSalt(); //generate random salt
        //newpass = newpass + salt; //append salt to newpass
        //hashed = hash.encryption(newpass); //hash newpass


        for (int i = 0; i < rows.Count; ++i)
        {

            if ((string)empTab.Rows[i]["username"] == username)//check if ID matches
            {
                empTab.Rows[i]["passwd"] = newpass;  //set passwd to hash new password                

                //check if dataset has changes
                if (dataset.HasChanges())
                {
                    //update database
                    dbAdapter.Update(dataset, "employee");
                    MessageBox.Show("Employee Updated!");
                    refreshTable();

                }
                else
                {
                    refreshTable();
                }
            }
        }

    }

I am trying to change a user's password when he is logged in.

  1. When he logs in, I want to capture his username through a textbox.

  2. After he logs in, there will be a main menu displayed.

  3. The user needs to click on the change password link and a change password form will appear.

Therefore, I need to pass the username from the login form to the change password form in order to use a change password function. However, the issue I am facing now is that the username does not get passed from the login form to the change password form.

Upvotes: 1

Views: 1047

Answers (4)

Steve
Steve

Reputation: 216343

You never show the Login form, how do you suppose that someone sets the textBox1 with an actual username?

You need something like this

       string username = string.Empty;
       Model_DB_Employee emp = new Model_DB_Employee();
       using(Login login = new Login())
       {      
             if(DialogResult.OK == login.ShowDialog())
              username = login.returnUsername();
       } 
       if(username == string.Empty)
       {
            MessageBox.Show("Username required");
            return;
       }

Upvotes: 0

Jodrell
Jodrell

Reputation: 35736

When, between these two lines, does the username in the new login get set?

Login login = new Login();
string username = login.returnUsername();

Upvotes: 1

Glauco Vinicius
Glauco Vinicius

Reputation: 2647

The problem is that with Login login = new Login() you´re shadowing your class instance variable login. Try:

private void buttonChangePass_Click(object sender, EventArgs e)
{
   Model_DB_Employee emp = new Model_DB_Employee();
   string username = login.returnUsername();

   if (textBoxNewPass.Text == string.Empty || textBoxConfirmPass.Text == string.Empty)
   {
       MessageBox.Show("Field cannot be empty!");
   }
   else
   {
       if (textBoxNewPass.Text == textBoxConfirmPass.Text)
       {
           try
           {
               emp.changePasswd(username,textBoxConfirmPass.Text);
               MessageBox.Show(username);
               MessageBox.Show("Password updated!");
               this.Hide();
               main.Show();
           }
           catch(SystemException ex)
           {
               MessageBox.Show("Password not updated" + ex);
           }
       }
       else
       {
           MessageBox.Show("Passwords do not match!");
       }
   }
}

Upvotes: 1

Servy
Servy

Reputation: 203825

The problem is the line:

Login login = new Login();

This is shadowing the login instance field with a new instance of Login as a local variable, so rather than accessing the Login created earlier that the user has interacted with, you're accessing a blank one. You can just delete the above line of code.

Upvotes: 3

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