Question

I’m coding a random seat generator for an airplane and I’m using a FOR loop in it. The thing is, the occupied seats only show when everything is done. What I would like it to do was in each iteration, show the random seat selected. How would one do that?

Here’s the code I’m using. The plane has 118 seats and I have a picturebox named “img_Seat_X” for each one of them. I know there’s a better way to this, but that’s I could think in a quick hour. Thanks in advance!

private void btn_WeightBalance_Populate_Click(object sender, EventArgs e)
{
                int passengers = Convert.ToInt32(txt_WeightBalance_Passengers.Text);
                List<int> seats = new List<int> { }; numberofSeats = 119;

                if (rdb_WeightBalance_190.Checked == true)
                    numberofSeats = 107;

                for (int x = 0; x < Passengers; x++)
                {
                    int randomNumber = RandomNumber(1, numberofSeats);

                    if (seats.Contains(randomNumber))
                        x--;

                    else
                    {

                        seats.Add(randomNumber);

                        Control[] seat = this.panWeightBalance.Controls.Find("img_Seat_" + randomNumber, true);
                        seat[0].Visible = true;
                        seat[0].Refresh();
                    }
                }
}

Figured it out! A simple Refresh() in each iteration did the job! I also replaced the while loop with an if statement.

Answer 1

First, required reading: The Windows Message Loop

@rice pointed out my obvious error, sorry for leading you down the wrong path, thanks rice.

Anyway, you can perform the work in a separate thread and post updates to the UI trhead using the BackgroundWorker class. Here is a simple example which updates a label on a form 100 times in response to a button click:

public partial class Form1 : Form
{
    BackgroundWorker _worker;
    public Form1()
    {
        InitializeComponent();
        _worker = new BackgroundWorker();
        _worker.WorkerReportsProgress = true;
        _worker.DoWork += _worker_DoWork;
        _worker.ProgressChanged += _worker_ProgressChanged;
    }

    private void _worker_ProgressChanged( object sender, ProgressChangedEventArgs e )
    {
        label1.Text = e.UserState.ToString();
    }

    private void _worker_DoWork( object sender, DoWorkEventArgs e )
    {
        for( int i = 0; i < 100; ++i )
        {
            _worker.ReportProgress( i, i );
            // allow some time between each update,
            // for demonstration purposes only.
            System.Threading.Thread.Sleep( 15 );
        }
    }   

    private void button1_Click( object sender, EventArgs e )
    {
        _worker.RunWorkerAsync();
    }
}