led blink every 2 seconds

Here's a simple example of how you can make an LED blink every 2 seconds using C# and the Windows Forms library.

```csharp
using System;
using System.Windows.Forms;

public class LedBlinker : Form
{
    private Timer timer;

    public LedBlinker()
    {
        // Initialize the form
        this.Text = "LED Blinker";
        this.Size = new System.Drawing.Size(300, 200);

        // Create a timer
        timer = new Timer();
        timer.Interval = 2000; // 2000 milliseconds = 2 seconds
        timer.Tick += new EventHandler(Timer_Tick);
        timer.Start();
    }

    private void Timer_Tick(object sender, EventArgs e)
    {
        // Toggle the LED's state
        this.BackColor = this.BackColor == System.Drawing.Color.Red ? System.Drawing.Color.White : System.Drawing.Color.Red;
    }

    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new LedBlinker());
    }
}
```

This code creates a simple Windows Form with a timer that toggles the form's background color every 2 seconds, simulating an LED blinking.

However, if you want to control an actual LED connected to a microcontroller or an Arduino board, you would need to use a different approach, such as using a serial communication library to send commands to the microcontroller.

Here's an example of how you can use the SerialPort class in C# to control an Arduino board:

```csharp
using System;
using System.IO.Ports;

public class LedBlinker
{
    private SerialPort serialPort;

    public LedBlinker()
    {
        // Initialize the serial port
        serialPort = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
        serialPort.Open();

        // Create a timer
        System.Timers.Timer timer = new System.Timers.Timer(2000);
        timer.Elapsed += new ElapsedEventHandler(Timer_Tick);
        timer.Start();
    }

    private void Timer_Tick(object sender, ElapsedEventArgs e)
    {
        // Toggle the LED's state
        serialPort.Write("1"); // Turn the LED on
        System.Threading.Thread.Sleep(1000);
        serialPort.Write("0"); // Turn the LED off
    }

    public static void Main()
    {
        LedBlinker ledBlinker = new LedBlinker();
    }
}
```

This code assumes that you have an Arduino board connected to your computer via a serial cable, and that you have written a sketch on the Arduino board that listens for serial commands to turn the LED on or off. The C# code sends these commands to the Arduino board every 2 seconds, simulating an LED blinking.