Question

As title states, my piece of code which was from an example provided by my professor.

My output is:

MagazineID Title Publisher Price SubscriptionRate 
1 People Times Inc. 4.95 19.95 
2 Car and Driver Hachetter Inc. 3.95 19.99 

Code:

    private void btnShowMags_Click(object sender, EventArgs e)
    {
        // Creating new instance of the DisplayMags form.
        DisplayMags displayMags = new DisplayMags();

        // find the path where the executable resides
        string dbPath = Application.StartupPath;

        // Providing a path to the MS Access file.
        string connString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source="
            + dbPath + @"\..\..\..\..\Magazines.mdb; User Id=admin; Password=";

        // Creating a new connection and assigning it to a variable.
        OleDbConnection conn = new OleDbConnection();
        conn.ConnectionString = connString;

        // Creating a new instance for a command which we will use later.
        OleDbCommand cmd = new OleDbCommand();
        cmd.Connection = conn;

        // declare and instantiate the command
        OleDbCommand cmdMagazines = new OleDbCommand();
        cmdMagazines.CommandText = "select * from magazine";
        cmdMagazines.Connection = conn;

        OleDbDataReader drMagazines;

        try
        {
            // open the connection
            conn.Open();

            // retrieve data from the data source to the data reader
            drMagazines = cmdMagazines.ExecuteReader();

            if (drMagazines.HasRows)
            {
                // populate the column headings
                for (int i = 0; i < drMagazines.FieldCount; i++)
                    displayMags.txtDisplayMags.Text += drMagazines.GetName(i) + " ";
                displayMags.txtDisplayMags.Text += "\r\n";

                // populate the data by row
                while (drMagazines.Read())
                {
                    for (int i = 0; i < drMagazines.FieldCount; i++)
                        displayMags.txtDisplayMags.Text += drMagazines.GetValue(i) + " ";
                    displayMags.txtDisplayMags.Text += "\r\n";
                }
            }
        }
        catch (Exception ex)
        {
            // Displaying any errors that might have occured.
            MessageBox.Show("Error opening the connection: " + ex.Message + "\r\n");
        }
        finally
        {
            // Closing connection after task was completed.
            conn.Close();
        }

        // Displaying DisplayMags form, assuring that earlier form
        // will not be accessible. Show() let us access all forms.
        displayMags.ShowDialog();
    }

And, I am trying to make it look like this:

EDIT. This work, but does this represent correct programming practices?

            if (drMagazines.HasRows)
            {
                while (drMagazines.Read())
                {
                    displayMags.txtDisplayMags.Text += "=== Magazine " + 
                        drMagazines.GetValue(0) + " ===" + Environment.NewLine + 
                        drMagazines.GetValue(1) + Environment.NewLine +
                        drMagazines.GetValue(2) + Environment.NewLine +
                        drMagazines.GetValue(3) + Environment.NewLine +
                        drMagazines.GetValue(4) + Environment.NewLine + 
                        Environment.NewLine;
                }
            }

Answer 1

I’m not giving you the entire answer, because that would defeat the purpose of the assignment and you wouldn’t learn anything. However, I can give you ideas on where to start to solve the problem.

Your output starts in the block starting with if (drMagazines.HasRows). The code within that block is where you need to make your changes.

You need to change it so that instead of printing out the column headings and then the content of each row, you print a separator that includes the magazine number, a line ending (Environment.NewLine) and then separate rows that have titles and then content.

You have the necessary information in your code now – you have comments where you populate the column headings and then populate the data by row. Change that so that you populate a single heading and then populate the row content for that heading. A suggestion would be to change it from two loops to one – read a column heading, and then the row content that it contains. You can add any additional content or formatting during that loop for each item.