C#

;
Socket socket;
IPEndPoint hostEndPoint;
string packet;
 
public void run()
{
  TCPConnect();

  packet = SendReceive("/signin.aspx", "GET");
  if (GetReturnCode(packet) == "400")
    TCPReset();

  packet = SendReceive("/index.html", "GET");

  TCPClose();  
}
 
private void TCPConnect()
{
  // Make sure there is a connection
  if (socket == null)
  {
    socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    hostEndPoint = new IPEndPoint(ipaddr, port);
  }

  socket.Connect(hostEndPoint);
}
 
// My problem is getting this function working properly
private void TCPReset()
{
  socket.Disconnect(true); // Close the socket connection and allow reuse of the socket
  socket.Connect(hostEndPoint); // This is ignored according to Ethereal,
                                // nothing is sent even using socket.Send()
}
 
private void TCPClose()
{
  socket.Shutdown(SocketShutdown.Both);
  socket.Close();
}
 
private string SendReceive(string strURI, strMethod)
{
  string pcAppend = " HTTP/1.1\r\nConnection: Keep-Alive\r\n\Content-Length: 0\r\n" +
      "User-Agent: Mozilla/4.0 (Compatible; MSIE 7.0; Windows NT 5.2; .NET CLR " +
      "2.0.50727; .NET CLR 3.0.04506.30; InfoPath.1; .NET CLR 3.5.21022)\r\n" +
      "Content-Type: application/x-www-form-urlencoded\r\nHost: " + strIPAddress + "\r\n\r\n";
  byte[] pcSend = System.Text.ASCIIEncoding.ASCII.GetBytes(strMethod + strURI + pcAppend);
  byte[] bfBuffer = new byte[10240];

  socket.Send(pcSend, pcSend.Length, 0);
  socket.Receive(bfBuffer, bfBuffer.Length, SocketFlags.None);

  return System.Text.ASCIIEncoding.ASCII.GetString(bfBuffer);
}

public class PictureBoxEx : ScrollableControl
    {
        private Image _image;
        private Single _zoom;
        private InterpolationMode _interpolationMode;
        private Point lastPos;        

        #region Properties

        [Category("Appearance"), Description("The image to be displayed.")]
        public Image Image
        {
            get { return _image; }
            set 
            { 
                _image = value;
                this.UpdateScaleFactor();
                this.Invalidate();
            }
        }

        [Category("Appearance"), Description("The zoom factor. Less than 1 to reduce. More than 1 to magnify.")]
        public Single Zoom
        {
            get { return _zoom; }
            set
            {
                _zoom = value;
                this.UpdateScaleFactor();
                this.Invalidate();
            }
        }

        [Category("Appearance"), Description("The interpolation mode used to smooth the drawing.")]
        public InterpolationMode InterpolationMode
        {
            get { return _interpolationMode; }
            set { _interpolationMode = value; }
        }

        public Point LastPosition
        {
            get { return lastPos; }
            set { lastPos = value; }
        }

        #endregion

        public PictureBoxEx()
        {
            this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.ResizeRedraw | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer, true);
            this.AutoScroll = true;
            this.Zoom = 1f;
        }

        private void UpdateScaleFactor()
        {
            if (this.Image == null)
                this.AutoScrollMargin = this.Size;
            else
                this.AutoScrollMinSize = new Size(Convert.ToInt32(this.Image.Width * this.Zoom + .5f), Convert.ToInt32(this.Image.Height * this.Zoom + .5f));
        }

        protected override void OnPaintBackground(PaintEventArgs e)
        {
            // Do nothing
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            if (this.Image == null)
            {
                this.OnPaintBackground(e);
                return;
            }
            Matrix mx = new Matrix(this.Zoom, 0, 0, this.Zoom, 0, 0);
            mx.Translate(this.AutoScrollPosition.X / this.Zoom, this.AutoScrollPosition.Y / this.Zoom);
            e.Graphics.Transform = mx;
            e.Graphics.InterpolationMode = this.InterpolationMode;
            e.Graphics.DrawImage(this.Image, new Rectangle(0, 0, this.Image.Width, this.Image.Height), 0, 0, this.Image.Width, this.Image.Height, GraphicsUnit.Pixel);
            base.OnPaint(e);
        }        
    }

private void buttonSaveXML_Click(object sender, EventArgs e)
{
    // DB1: Read table1 in DataSet and write in XML-File: works OK
    OleDbConnection conn = new OleDbConnection
        ("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=TestDataTable.mdb;");
    conn.Open();
    DataSet ds = new DataSet("test-DS");
    OleDbDataAdapter da = new OleDbDataAdapter("select keycol, col1, col2 from table1", conn);
    da.Fill(ds, "table1");
    ds.WriteXml("test-DS.xml", XmlWriteMode.WriteSchema);
    conn.Close();
    // 2 rows of Data in columns   keycol, col1, col2   with values:
    // row1     col1row1    col2row1
    // row2     col1row2    col2row2
}

private void buttonReadXML_Click(object sender, EventArgs e)
{
    // !!!! To simulate the second DB: Database has changed: row1 is deleted. col1row2 has changed its value. !!!!
    // This should restore table1 to original values (insert row1, update row2)
    // Read DS from XML-File.
    OleDbConnection conn = new OleDbConnection
        ("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=TestDataTable.mdb;");
    conn.Open();
    DataSet ds = new DataSet("test-DS");
    ds.ReadXml("test-DS.xml", XmlReadMode.ReadSchema);
    // use DataAdapter to do the whole work
    OleDbDataAdapter da = new OleDbDataAdapter("select keycol, col1, col2 from table1", conn);
    da.ContinueUpdateOnError = true; // no break on error (e.g. row with same key-value)
    OleDbCommandBuilder cb = new OleDbCommandBuilder(da);
    cb.ConflictOption = ConflictOption.OverwriteChanges; // Update changes of non-key columns
    DataTable dt = ds.Tables["table1"];

    ////////////////////////
    // first Update(): because all datarows have RowState ADDED, this inserts row1
    // row2 leads to error, because key row2 exists (but still is OK!)
    string trace_command = cb.GetInsertCommand(true).CommandText;
    // INSERT INTO table1 (keycol, col1, col2) VALUES (?, ?, ?)
    int updcount = da.Update(dt);  // does one INSERT
    MessageBox.Show("first da.Update() does INSERT on " + updcount.ToString() + " rows.\n" +
        "InsertCommand is: " + trace_command);
    for (int index = dt.Rows.Count - 1; index >= 0; index--)
        if (!dt.Rows[index].HasErrors)
            dt.Rows.Remove(dt.Rows[index]); // if no error in row: it was inserted, so remove it

    ////////////////////////
    // second Update(): intension is to update col1 in row2
    dt.AcceptChanges();     // datarows: RowState was ADDED, now UNCHANGED
                            // SetModified causes exception, if RowState is ADDED
    foreach (DataRow dr in dt.Rows)
        dr.SetModified();   // now: dr.RowState is MODIFIED. ==> should invoke UPDATE
    trace_command = cb.GetUpdateCommand(true).CommandText;
    // UPDATE table1 SET keycol = ?, col1 = ?, col2 = ? WHERE ((keycol = ?))
    updcount = da.Update(dt);
    MessageBox.Show("second da.Update() on " + updcount.ToString() + " rows.\n" +
        "UpdateCommand is: " + trace_command);
    // This does 1 Update, but the col1row2 value is NOT updated!!!
    // This is the problem: it seems that the UPDATE-Command only updates "changed" values!
    // But how to tell the DataRow.Item, that it has changed????

    ////////////////////////
    // What i did, to mark the item as changed: save, change and restore the value!
    // But I think, there are better ways to do this???
    dt.AcceptChanges();
    foreach (DataRow dr in dt.Rows)
    {
        string save = dr["col1"].ToString();
        dr["col1"] = "new changed value";
        dr.AcceptChanges();
        dr["col1"] = save;
    }
    updcount = da.Update(dt);

    conn.Close();
}