First of all we have to design a table in database in order to store the user and password of the entire user who can log on to our application having at least two entities ‘username’ and ‘password’ , here my database name is ‘Employee’ and table name is ‘login’.

Our next step is to design login form.

 

Set the password text box ‘password char’ to ‘*’.

Now, once the login form and tables are designed our next step is to design the code for the login form.

Coding
        Boolean log = false;
 
//Assigning public variable log of type Boolean to set property of this from
//in order to access it from  other form.
 
        public Login()
        {
            InitializeComponent();
        }
       
        private void btnCancel_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
 
//Application will exit if cancel button is clicked.
 
        public void fnlogin()
        {
 
//Function for login
 
            try
            {
 
//Managing connection to the database
 
                string sqlString = "Server=abc\\SQLEXPRESs;Database=Employee;Trusted_Connection=True";
                SqlConnection con = new SqlConnection(sqlString);
                con.Open();
                SqlCommand cmd = new SqlCommand("select UserName, Password from login whereUserName='" + txtUserName.Text.Trim() + "' and Password='" + txtPassword.Text.Trim() + "'", con);
 
//Fetching only those records from the table which matches with the record
//in the text field in the login form.
                SqlDataReader rdr = cmd.ExecuteReader();
                if (rdr.HasRows)
                {
 
//checking whether datareader contains any rows or not. If the condition
//is true then the code below will be executed otherwise code in else
//block will be executed.
 
                    while (rdr.Read())
                    {  
//Reading all records fetched, one by one and matching with the user name
//and password entered by user, in order to overcome small and upper caps
//complexities in user name and password.
                        if (rdr[0].ToString().ToUpper() ==txtUserName.Text.Trim().ToUpper() && txtPassword.Text==rdr[1].ToString())
                        {
                            log= true;
                            this.Close();
                        }
                        else
                        {
//If username or password provider by the user are incorrect then
//following message will be displayed.
                            MessageBox.Show("User Name or Password incorrect!!!");
                            txtUserName.Text= "";
                            txtPassword.Text= "";
                            txtUserName.Focus();
                            log= false;
                        }
                    }
                                 
                }
                else
                {
                    MessageBox.Show("User Name or Password incorrect!!!");
                    txtUserName.Text = "";
                    txtPassword.Text = "";
                    txtUserName.Focus();
                    log = false;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void btnLogin_Click(object sender, EventArgs e)
        {
            fnlogin();           
        }
 
        private void txt_KeyPress(object sender, KeyPressEventArgs e)
        {
//Checking whether enter key is pressed in text boxes or not.
            if (e.KeyChar == (char)13)
                fnlogin();
        }
 
//Setting property of this form in order to use it in another form
//so as to get the information whether the login was successful or not.
        public Boolean pLog
        {
            get
            {
                return log;
            }
            set
            {
                log = value;
            }
        }


Screen Shot

 

Message displayed if username and password provider are incorrect.

 

  1. hi Haider M Rizvi ,

      this code is have problem.

    if (rdr[0].ToString().ToUpper() == txtUserName.Text.Trim().ToUpper() && txtPassword.Text==rdr[1].ToString())

    if database exist this username and password also will not right login.

  1. Hi Aken H,

    Here while writing code it is assumed that first field is UserName and secondField is password so that it predict correct answer as I execute this code.

    You can change rdr[0] to rdr["UserName"] and rdr[1] to rdr["Password"] where UserName and Password .

    you can add this line of code at end of catch block.

    if(log)

         MessageBox.Show("Login Successful");

    else

         MessageBox.Show("Login Failed.");

    Thanks.

  1. Hi Awadhendra Tiwari ,

      you can modify this code do

Leave Comment