C#

[StructLayout(LayoutKind.Sequential)]
private struct RECT
{
   int left;
   int top;
   int right;
   int bottom;
 
   public static RECT FromLTRB( int l, int t, int r, int b )
   {
      RECT rc = new RECT();
 
      rc.left   = l;
      rc.top    = t;
      rc.right  = r;
      rc.bottom = b;
 
      return rc;
   }
 
   public static RECT FromRectangle( Rectangle r )
   {
      return FromLTRB( r.Left, r.Top, r.Right, r.Bottom );
   }
}
 
private const int IDANI_CAPTION = 3;
 
// Thanks to www.pinvoke.net
[DllImport("user32.dll")]
private static extern bool DrawAnimatedRects( HandleRef hwnd, int idAni,
   [In] ref RECT lprcFrom, [In] ref RECT lprcTo);
 
private void OnClosing(object sender, System.ComponentModel.CancelEventArgs e)
{
   if ( exiting )
      return;
 
   e.Cancel = true;
 
   // Do the animation
   // Aim for a 16x16 box in the corner - we can't easily work out exactly where we'll be
   Rectangle boundsRect = Screen.PrimaryScreen.Bounds;
   RECT rcFrom = RECT.FromRectangle( Bounds );
    
   RECT rcTo = 
      RECT.FromLTRB( 
         boundsRect.Right - 16,
         boundsRect.Bottom - 16,
         boundsRect.Right,
         boundsRect.Bottom );
 
   DrawAnimatedRects( new HandleRef( this, Handle ), IDANI_CAPTION, ref rcFrom, ref rcTo );
 
   // Hide the form
   Visible = false;
}

private void OnNotifyIconClick(object sender, System.EventArgs e)
{
   if ( Visible )
      return;
 
   // Animate back to our normal position
   // Aim for a 16x16 box in the corner - we can't easily work out exactly where we'll be
   Rectangle boundsRect = Screen.PrimaryScreen.Bounds;
   RECT rcTo = RECT.FromRectangle( Bounds );
   RECT rcFrom = 
      RECT.FromLTRB( 
         boundsRect.Right - 16,
         boundsRect.Bottom - 16,
         boundsRect.Right,
         boundsRect.Bottom );
 
   DrawAnimatedRects( new HandleRef( this, Handle ), IDANI_CAPTION, ref rcFrom, ref rcTo );
 
   // and show
   Visible = true;
}
 
private void exit_Click(object sender, System.EventArgs e)
{
   exiting = true;
   Close();
}
 
private bool exiting;

HttpWebRequest request = (HttpWebRequest)
  WebRequest.Create("http://www.umc.ua/misc/sendsms.php");
request.Method = "POST"
request.ContentType = "application/x-www-form-urlencoded";
string postData =
  "network1=UMC&Phone1=5918658&Message=HellofromCSharp&sender_name=sn";
byte[] buffer = Encoding.ASCII.GetBytes(postData);
request.ContentLength = buffer.Length;
Stream s = request.GetRequestStream();
s.Write(buffer, 0, buffer.Length);
s.Flush();
s.Close();
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// ...

using System;
using System.Drawing;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;

[assembly: AssemblyVersion("1.0.*")]
[assembly: AssemblyKeyFile(@"C:\Path\To\KeyFile.snk")] // sn.exe -k KeyFile.snk

namespace Test
{
  [Guid("0eea66bf-21bf-4c8c-8678-ad58106343a7")]
  [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
  public interface ITest
  {
    [DispId(0)]
    DialogResult ShowDialog();
  }

  [ClassInterface(ClassInterfaceType.None)]
  [Guid("861e1098-7705-4686-945e-236a0ef439ef")]
  [ProgId("Test.Test")]
  public class Test : Form, ITest
  {
    static void Main()
    {
      Application.Run(new Test());
    }

    public Test()
    {
      SuspendLayout();

      Text = "Out-of-Proc Server Test";

      Label lbl = new Label();
      Controls.Add(lbl);
      lbl.Location = new Point(8, 8);
      lbl.Text = "Hello, world!";

      ResumeLayout();
    }
  }
}

regasm.exe /tlb /codebase Test.exe

var test = new ActiveXObject("Test.Test");
test.ShowDialog();

csc /t:exe Test.cs