Creating an Accounting Application With C# - Part Four

Finally, we save the properties.settings.

Properties.Settings.Default.Save(); 

The entire code under Activation Form Loading event is as follows.

private static TimeZoneInfo INDIAN_ZONE = TimeZoneInfo.FindSystemTimeZoneById("India Standard Time");
private void ActivationFour_Load(object sender, EventArgs e)
{
    // Firstly we check whether we already stored the Code or not
    if (Properties.Settings.Default.SystemCode == string.Empty)
    {
        DateTime indianTime = 
            TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, INDIAN_ZONE);
        int mnts = indianTime.Minute;
        int hour = indianTime.Hour;
        int day_in_month = indianTime.Day;
        int month = indianTime.Month;
        int day_in_year = indianTime.DayOfYear;
        int year = indianTime.Year;
        string rslt = "N" + mnts.ToString() + "u" + hour.ToString() + "Y" +
            day_in_month.ToString() + "t" + month.ToString() + "r" +
            day_in_year.ToString();
        Properties.Settings.Default.SystemCode = rslt;
        int otp = mnts * hour * day_in_month * month * year;
        Properties.Settings.Default.ActivationKey = otp;
        Properties.Settings.Default.Save();
    }
    txtSystemCode.Text = Properties.Settings.Default.SystemCode;
}

Then we write code under the submit button and click the event.

Login login;
private void btnSubmit_Click(object sender, EventArgs e)
{
    if (txtActivationKey.Text == Properties.Settings.Default.ActivationKey.ToString())
    {
        this.Hide();
        login = new Login();
        login.Show();
    }
    else
    {
        MessageBox.Show("The entered Activation Code is not correct. Please check and try again", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

If the entered activation key is correct, then the current activation form is hiding and the login form is showing. Otherwise, show an error report.

Login window

To get web model text boxes and buttons, we used user controls. We will discuss creating and applying user control in the upcoming sessions. Now let us discuss the code behind the login button.

In this form, we used Ado.net code to retrieve data from the database. In the upcoming sessions, we will use Stored Procedure, Ling, and Entity Framework.

Firstly we have to call the namespace in the section.

using System.Data.SqlClient; 

In the Login button click event we want to write the following code.

First, we have to call the connection string. Here we have stored the connection string in Properties.settings; to know more about this method please read my article from here.

string strConnection = Properties.Settings.Default.strConnectionString;

Here we implement using statements to connect to the database. There are many benefits to using a statement. The using statement automatically calls the Dispose() method while leaving the scope of the statement. Using a statement is a more elegant way of disposing of the object than manual disposal. So using statements is a good practice.

The query used here is to collect the count of the user with the given Username and password. If the count is one, then the username and password entered is correct.

string Query = "Select Count(*) From [User] where UserName = '" + txtUserName.Text.ToUpper() + "' and PassWord = '" + txtPWord.Text + "'";

If the count is one, then the username and password entered is correct.

Then the current form is hidden and the main form will open.

if (dt.Rows[0][0].ToString() == "1")
{
    main = new Main();
    this.Hide();
    main.Show();
}

To Call the Main form class we have to declare the form class first. We are declaring the main form before the button event.

Main main;  

We declare two strings for validation error messages.

string msg1 = "Please check your Username and Password";
string msg2 = "Please enter Username and Password";

If the result is not ‘one’ then show the first message and clear both textboxes.

else
{
    MessageBox.Show(msg1, "Error");
    txtUserName.Text = string.Empty;
    txtPWord.Text = string.Empty;
    txtUserName.Focus();
}

The entire code is as follows.

Main main;
private void btnLoggin_Click(object sender, EventArgs e)
{
    string strConnection = Properties.Settings.Default.strConnetionString;
    try
    {
        string Query = "Select Count(*) From [User] where UserName = '" + txtUserName.Text.ToUpper() + "' and PassWord = '" + txtPWord.Text + "'";
        using (SqlConnection con = new SqlConnection(strConnection))
        {
            using (SqlDataAdapter da = new SqlDataAdapter(Query, con))
            {
                DataTable dt = new DataTable();
                da.Fill(dt);
                string msg1 = "Please check your Username and Password";
                string msg2 = "Please enter Username and Password";
                if (txtUserName.Text != string.Empty & txtPWord.Text != string.Empty)
                {
                    if (dt.Rows[0][0].ToString() == "1")
                    {
                        main = new Main();
                        this.Hide();
                        main.Show();
                    }
                    else
                    {
                        MessageBox.Show(msg1, "Error");
                        txtUserName.Text = string.Empty;
                        txtPWord.Text = string.Empty;
                        txtUserName.Focus();
                    }
                }
                else
                {
                    MessageBox.Show(msg2, "Error");
                    txtUserName.Text = string.Empty;
                    txtPWord.Text = string.Empty;
                    txtUserName.Focus();
                }
            }
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

Summary

In this article, we learned about the splash screen, progress bar, finding current minutes, hours, month, day in the month, year, and day in the year from a datetime and we understand the method behind the activation window and code behind the Login button in detail.

References

• Creating Accounting Application with C# Tutorial - Part One
• Creating Accounting Application with C # Tutorial Part Two
• Creating Accounting Application with C # Tutorial Part Three
• A Simple Way To Change SQL Server Connection String Programmatically In C#

Conclusion

Thank you for reading my article. If you feel the article is useful please like and share the same with your friends and colleagues. And also please put comments about the article in the comment section. This will be very encouraging to me to write the subsequent chapters. If you want the entire source code you can contact me in my e-mail [email protected]

In the next session, we will discuss implementing a three-tier architecture.

Three-tier architecture provides many key benefits for the production and development of applications by modularizing the user interface, business logic, and data layers. Doing so gives greater flexibility to the development teams by allowing them to update a specific part of the application independently.

Most of the software companies are following this method. So I think the following sessions will be more helpful to students and beginners to get jobs. So please wait and see.

Thank you.