WinForms 跨窗傳動事件範例

CrossFromsDemo.cs

using System;
using System.Windows.Forms;

namespace CrossFromsDemo
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            Application.SetHighDpiMode(HighDpiMode.SystemAware);
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new MainForm());
        }
    }

    public class MainForm : Form
    {
        Button Open2ndFormButton;

        public MainForm()
        {
            Text = GetType().Name;

            Open2ndFormButton = new Button { Text = "Open 2nd Form", Dock = DockStyle.Fill };
            Open2ndFormButton.Click += OnClick_OpenSecondFormButton;
            Controls.Add(Open2ndFormButton);
        }

        void OnClick_OpenSecondFormButton(object sender, EventArgs e)
        {
            Open2ndFormButton.Enabled = false;

            var secondForm = new SecondForm();
            // 註冊第二窗開放出來的按鈕事件
            secondForm.ActionButtonClick += OnClick_SecondFormAction;
            secondForm.Show(this);
        }

        void OnClick_SecondFormAction(object sender, EventArgs e)
        {
            // 第二窗的的按鈕事件發生就復原按鈕
            Open2ndFormButton.Enabled = true;
        }
    }
    
    public class SecondForm : Form
    {
        Button ActionButton;

        // 開事件出去給其他人
        public event EventHandler ActionButtonClick;

        public SecondForm()
        {
            Text = GetType().Name;

            ActionButton = new Button { Text = "Action", Dock = DockStyle.Fill };
            ActionButton.Click += OnClick_ActionButton;
            Controls.Add(ActionButton);
        }

        void OnClick_ActionButton(object sender, EventArgs e)
        {
            // 觸發開放出去的事件通知其他人
            ActionButtonClick?.Invoke(sender, e);
        }
    }
}