C#

abstract public class MyBaseClass1 : Form
{
    abstract public void MyMethod1();
}

abstract public class MyBaseClass2 : Form
{
    abstract public void MyMethod2();
}

public partial class Form1 : MyBaseClass1
{
    public Form1()
    {
        InitializeComponent();
    }

    public override void MyMethod1()
    {
        MessageBox.Show("mymethod1");
    }
}

          [System.Runtime.InteropServices.DllImport("user32.dll")]
            public static extern bool RegisterHotKey(
            IntPtr hWnd, // handle to window          
            int id, // hot key identifier          
            uint fsModifiers, // key-modifier options         
            Keys vk // virtual-key code            
            );
.....
RegisterHotKey(Handle, 150, 2|4, Keys.A);//Ctrl+Shift+A
.....

        private void ProcessHotkey(Message m)  
        {
            IntPtr id = m.WParam; //                    
            string sid = id.ToString();
            switch (sid)
            {
                case "150": SayHello(); break;// Press Ctrl+Shift+A,call function:SayHello(); 
                .....      
            }        
        }
.......


        private void SayHello()
        {
            MessageBox.Show("Hello!"); 
        }

private void fileSystemWatcher1_Created(object sender, System.IO.FileSystemEventArgs e)
       {
           listBox1.Items.Add(e.FullPath);
           listBox2.Items.Add(e.FullPath);
           listBox1.SelectedIndex = listBox1.Items.Count - 1;
           listBox1.SelectedIndex = -1;
           listBox2.SelectedIndex = listBox2.Items.Count - 1;
           listBox2.SelectedIndex = -1;
       }

       private void listBox1_Click(object sender, EventArgs e)
       {
           listBox2.SelectedIndex = listBox1.SelectedIndex;
       }

       private void listBox2_Click(object sender, EventArgs e)
       {
           int itemSelected = this.listBox2.SelectedIndex;
           string itemText = this.listBox2.Items[itemSelected].ToString();

           Rectangle r = this.listBox2.GetItemRectangle(itemSelected);
           this.textBox1.Location = new System.Drawing.Point(r.X + 217, r.Y + 520);
           this.textBox1.Size = new System.Drawing.Size(r.Width + 4, r.Height - 10);
           this.textBox1.Visible = true;
           this.textBox1.Text = itemText;
           this.textBox1.Focus();
           this.textBox1.SelectAll();
       }

       private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
       {
           if (e.KeyChar == 13)
           {
               this.listBox2.Items[this.listBox2.SelectedIndex] = this.textBox1.Text;

               this.textBox1.Visible = false;
           }
           if (e.KeyChar == 27)
               this.textBox1.Visible = false;
       }