How to remember last closed form

Question

Hi ,

Working on a application , where i have two pages in my application : sale and purchase . I need to find out on which form i was working before closing the application , so that it can be the starting form of my application at run time . For example , if i was working on sale page and then i closed the application , then on next start of my application , sales should be opened first .

            if () // if last page closed  was sale 
            {
                this.BackColor = Color.FromArgb(227, 220, 192);
                this.VoucherType.Text = "Sales";
                this.label1.Text = "Reference no.:";
                label2.Hide();
                textBox2.Hide();

            }
            else if () // if last page closed was purchase 
            {
                this.BackColor = Color.FromArgb(250, 43, 198);
                this.VoucherType.Text = "Purchase";
                this.label1.Text = "Supplier Invoice no.:";
                label2.Show();
                textBox2.Show();

            }

Answer 1

1. Create a field to record the last closed form
2. Create class that inherits ApplicationContext to save the LastForm

class SaveLastFormContext : ApplicationContext
{
    public SaveLastFormContext(Form firstForm) : base(firstForm) { }

    protected override void OnMainFormClosed(object sender, EventArgs e) {
        foreach (Form form in Application.OpenForms) {
            if (form.TopLevel && !form.InvokeRequired) {
                MainForm = form;
                return;
            }
        }
        // Save LastForm TypeName
        var settings = MyApp.Properties.Settings.Default;
        settings.LastForm = MainForm.GetType().Name;
        settings.Save();
        base.OnMainFormClosed(sender, e);
    }
}

3. Main as follows

namespace MyApp
{
    internal static class Program
    {
        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            // choise FirstForm
            var settings = MyApp.Properties.Settings.Default;
            string lastForm = settings.LastForm;
            Form firstForm;
            switch (lastForm) {
                case "Sale":
                    firstForm = new Sale();
                    break;
                default:
                    firstForm = new Purchase();
                    break;
            }
            Application.Run(new SaveLastFormContext(firstForm));
        }
    }
}