C# WinForm - loading screen

Question

I would like to ask how to make a loading screen (just a picture or something) that appears while the program is being loaded, and disappears when the program has finished loading.

In fancier versions, I have seen the process bar (%) displayed. how can you have that, and how do you calculate the % to show on it?

I know there is a Form_Load() event, but I do not see a Form_Loaded() event, or the % as a property / attribute anywhere.

Answer 1

all you need to create one form as splash screen and show it before you main start showing the landing page and close this splash once the landing page loaded.

using System.Threading;
using System.Windows.Forms;

namespace MyTools
{
    public class SplashForm : Form
    {
        //Delegate for cross thread call to close
        private delegate void CloseDelegate();

        //The type of form to be displayed as the splash screen.
        private static SplashForm splashForm;

        static public void ShowSplashScreen()
        {
            // Make sure it is only launched once.    
            if (splashForm != null) return;
            splashForm = new SplashScreen();
            Thread thread = new Thread(new ThreadStart(SplashForm.ShowForm));
            thread.IsBackground = true;
            thread.SetApartmentState(ApartmentState.STA);
            thread.Start();
        }

        static private void ShowForm()
        {
            if (splashForm != null) Application.Run(splashForm);
        }

        static public void CloseForm()
        {
            splashForm?.Invoke(new CloseDelegate(SplashForm.CloseFormInternal));
        }

        static private void CloseFormInternal()
        {
            if (splashForm != null)
            {
               splashForm.Close();
               splashForm = null;
            };
        }
    }
}

and the main program function looks like this:

[STAThread]
static void Main(string[] args)
{
    SplashForm.ShowSplashScreen();
    MainForm mainForm = new MainForm(); //this takes ages
    SplashForm.CloseForm();
    Application.Run(mainForm);
}

Don't forget to add a form load event to your main form:

private void MainForm_Load(object sender, EventArgs e)
{
    this.WindowState = FormWindowState.Minimized; 
    this.WindowState = FormWindowState.Normal;
    this.Focus(); this.Show();
}

It will bring the main form to the foreground after hiding the splash screen.