How to zoom image from webcam in C# use VS2008?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Dynamsoft.DotNet.TWAIN.Enums;
using Dynamsoft.DotNet.TWAIN.WebCamera;
using System.IO;
using System.IO.Ports;
using System.Xml;

namespace trial1
{
    public partial class Form1 : Form
    {
        SerialPort P = new SerialPort();
        string InputData = String.Empty;
        delegate void SetTextCallback(string text);
        public Form1()
        {
            InitializeComponent();
            string[] port = SerialPort.GetPortNames();
            cbCom.Items.AddRange(port);
            dynamicDotNetTwain1.IfShowUI = true;
            dynamicDotNetTwain1.SupportedDeviceType = EnumSupportedDeviceType.SDT_WEBCAM;
            dynamicDotNetTwain1.IfThrowException = true;
            P.ReadTimeout = 1000;
            P.DataReceived += new SerialDataReceivedEventHandler(DataReceive);
            dynamicDotNetTwain2.IfShowUI = true;
            dynamicDotNetTwain2.SupportedDeviceType = EnumSupportedDeviceType.SDT_WEBCAM;
            dynamicDotNetTwain2.IfThrowException = true;
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
        private void DataReceive(object obj, SerialDataReceivedEventArgs e)
        {
            InputData = P.ReadExisting();
            if (InputData != String.Empty)
            {
                SetText(InputData);
            }
        }
        private void SetText(string text)
        {
            if (this.txtNhan.InvokeRequired)
            {
                SetTextCallback d = new SetTextCallback(SetText);
                this.Invoke(d, new object[] { text });
            }
            else this.txtNhan.Text += text;
        }
        private void button2_Click(object sender, EventArgs e)
        {
            try
            {
                dynamicDotNetTwain1.SelectSource();
                dynamicDotNetTwain1.SetVideoContainer(pictureBox1);
                dynamicDotNetTwain1.OpenSource();
                txtSource.Text = dynamicDotNetTwain1.CurrentSourceName;
                int count = dynamicDotNetTwain1.ResolutionForCamList.Count;
                for (int j = 0; j < count; j++)
                {
                    string tempHeight = dynamicDotNetTwain1.ResolutionForCamList[j].Height.ToString();
                    string tempWidth = dynamicDotNetTwain1.ResolutionForCamList[j].Width.ToString();
                    string tempResolution = tempWidth + "X" + tempHeight;
                    comboBox1.Items.Insert(j, tempResolution);
                    comboBox1.SelectedIndex = 0;
                }
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            dynamicDotNetTwain1.ResolutionForCam = dynamicDotNetTwain1.ResolutionForCamList[comboBox1.SelectedIndex];
        }

        private void btnConnect_Click(object sender, EventArgs e)
        {
            if (btnConnect.Text == "Connect")
            {
                P.Open();
                MessageBox.Show("Connected!", "Congratulation!");
                btnConnect.Text = "Disconnect";
            }
            else if (btnConnect.Text == "Disconnect")
            {
                btnConnect.Text = "Connect";
                P.Close();
            }
        }

        private void txtNhan_TextChanged(object sender, EventArgs e)
        {
            if (txtNhan.Text == "115")
            {
                try
                {
                    dynamicDotNetTwain1.EnableSource();
                }
                catch (Exception exp)
                {
                    MessageBox.Show(exp.Message);
                }
                txtNhan.Text = "";
            }
            else if (txtNhan.Text == "116")
            {
                try
                {
                    dynamicDotNetTwain2.EnableSource();
                }
                catch (Exception exp)
                {
                    MessageBox.Show(exp.Message);
                }
                txtNhan.Text = "";
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                dynamicDotNetTwain2.SelectSource();
                dynamicDotNetTwain2.SetVideoContainer(pictureBox2);
                dynamicDotNetTwain2.OpenSource();
                txtSource.Text = dynamicDotNetTwain2.CurrentSourceName;
                int counter = dynamicDotNetTwain2.ResolutionForCamList.Count;
                for (int i = 0; i <counter;>                {
                    string tempHeight = dynamicDotNetTwain2.ResolutionForCamList[i].Height.ToString();
                    string tempWidth = dynamicDotNetTwain2.ResolutionForCamList[i].Width.ToString();
                    string tempResolution = tempWidth + "X" + tempHeight;
                    comboBox2.Items.Insert(i, tempResolution);
                    comboBox2.SelectedIndex = 0;
                }
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }

        private void cbCom_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (P.IsOpen)
            {
                P.Close();
            }
            P.PortName = cbCom.SelectedItem.ToString();
        }
    }
}