C# code compile problem.

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 System.Runtime.InteropServices;

namespace LED_Display

{

    public partial class Form1 : Form

    {

        private Bitmap myBitmap;

        int i = 0;

        int j = 0;

        public byte[] SendData = new byte[1];

        public class Win32APICall

        {

            [DllImport("gdi32.dll", EntryPoint = "DeleteDC")]

            public static extern IntPtr DeleteDC(IntPtr hdc);

            [DllImport("gdi32.dll", EntryPoint = "DeleteObject")]

            public static extern IntPtr DeleteObject(IntPtr hObject);

            [DllImport("gdi32.dll", EntryPoint = "BitBlt")]

            public static extern bool BitBlt(IntPtr hdcDest, int nXDest,

                int nYDest, int nWidth, int nHeight, IntPtr hdcSrc,

                int nXSrc, int nYSrc, int dwRop);

            [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleBitmap")]

            public static extern IntPtr CreateCompatibleBitmap(IntPtr hdc,

                int nWidth, int nHeight);

            [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleDC")]

            public static extern IntPtr CreateCompatibleDC(IntPtr hdc);

            [DllImport("gdi32.dll", EntryPoint = "SelectObject")]

            public static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobjBmp);

            [DllImport("user32.dll", EntryPoint = "GetDesktopWindow")]

            public static extern IntPtr GetDesktopWindow();

            [DllImport("user32.dll", EntryPoint = "GetDC")]

            public static extern IntPtr GetDC(IntPtr hWnd);

            [DllImport("user32.dll", EntryPoint = "GetSystemMetrics")]

            public static extern int GetSystemMetrics(int nIndex);

            [DllImport("user32.dll", EntryPoint = "ReleaseDC")]

            public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);

            public static Bitmap GetDesktop()

            {

                IntPtr hBmp;

                IntPtr hdcScreen = GetDC(GetDesktopWindow());

                IntPtr hdcCompatible = CreateCompatibleDC(hdcScreen);

                int screenX;

                int screenY;

                screenX = GetSystemMetrics(0) ;

                screenY = GetSystemMetrics(1) ;

                hBmp = CreateCompatibleBitmap(hdcScreen, screenX, screenY);

                if (hBmp != IntPtr.Zero)

                {

                    IntPtr hOldBmp = (IntPtr)SelectObject(hdcCompatible, hBmp);

                    //BitBlt(hdcCompatible, 0, 0, screenX, screenY, hdcScreen, 0, 0, 13369376);

                    BitBlt(hdcCompatible, 0, 0, screenX, screenY, hdcScreen, 0, 0, 13369376);

                    SelectObject(hdcCompatible, hOldBmp);

                    DeleteDC(hdcCompatible);

                    ReleaseDC(GetDesktopWindow(), hdcScreen);

                    Bitmap bmp = System.Drawing.Image.FromHbitmap(hBmp);

                    DeleteObject(hBmp);

                    GC.Collect();

                    return bmp;

                }

                return null;

            }

        }

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            serialPort1.Open();

        }

        private void led_send()

        {

            myBitmap = Win32APICall.GetDesktop();

            //Graphicsオブジェクトの作成

            　Graphics g = groupBox1.CreateGraphics();

            for (int y = 0; y < 32; y++)

            {

                j = j + 7;

                for (int x = 0; x < 32; x++)

                {

                    i = i + 7;

                    try

                    {

                        Color myColor = myBitmap.GetPixel(MousePosition.X + (31 - x) * (int)(numericUpDown1.Value), MousePosition.Y + y * (int)(numericUpDown1.Value));

　　　　　　　　　　　　　　//Brushオブジェクトの作成

                        　　SolidBrush b = new SolidBrush(myColor);

                        //(10,20,100,80)の長方形を塗りつぶす

                        　　g.FillRectangle(b, 240 - i, 10 + j, 5, 5);

                        //Color myColor2 = myBitmap.GetPixel(MousePosition.X, MousePosition.Y);

                        //textBox1.Text = myColor2.R.ToString();

                        //textBox2.Text = myColor2.G.ToString();

                        //textBox3.Text = myColor2.B.ToString();

                        if (radioButton1.Checked)

                        {

                            SendData[0] = Convert.ToByte(myColor.R);

                        }

                        if (radioButton2.Checked)

                        {

                            SendData[0] = Convert.ToByte(myColor.G);

                        }

                        if (radioButton3.Checked)

                        {

                            SendData[0] = Convert.ToByte(myColor.B);

                        }

                        serialPort1.Write(SendData, 0, 1);//送信

                    }

                    catch

                    {

                    }

                }

                i = 0;

            }

            j = 0;

        }

        private void timer1_Tick(object sender, EventArgs e)

        {

            led_send();

        }

    }

}