i am doing a program to block ip address . First i import the list of ip address from 2 table of sql database. Then the third datagridview will show the ip address that difference in the 1st and second datagridview. Here is what I have so far...

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.Data.SqlClient;
using System.Configuration;
using System.IO;
using System.Runtime.InteropServices;
using Excel;


namespace testingpurpose
{

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void BindDataGrid()
        {
            SqlConnection myConn = new SqlConnection();
            myConn.ConnectionString = ConfigurationManager.ConnectionStrings["myConn"].ToString();

            myConn.Open();

            string strSQL = "SELECT * FROM FAT_Table WHERE Type IN ('NoteBook','Desktop')";
            SqlDataAdapter dataAdapter = new SqlDataAdapter(strSQL, myConn);
            SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
            //SqlCommand cmd = new SqlCommand("select user_id from profile where user_id = " + StaticData.ActiveUserId + "", myConn);

            DataTable table = new DataTable();
            dataAdapter.Fill(table);
            BindingSource.DataSource = table;
            dataGridView.ReadOnly = true;    
            dataGridView.DataSource = BindingSource;

            myConn.Close();
        }
   

        private void btnBrowse_Click_1(object sender, EventArgs e)
        {
            OpenFileDialog openFD = new OpenFileDialog();

            openFD.CheckFileExists = true;
            openFD.InitialDirectory = "Desktop";
            openFD.Title = "Select a File";
            openFD.FileName = "";
            openFD.Multiselect = false;
            openFD.Filter = "All Files (*.*)|*.*|Excel Files (*.xls)|*.xls|CSV Files (*.csv*)|*.csv";

            if (openFD.ShowDialog() == DialogResult.OK)
            {
                this.txtPath.Text = openFD.FileName;

            }
        }

        private void btnImport_Click(object sender, EventArgs e)
        {
            if (txtPath.Text == "")
            {
                MessageBox.Show("Please select a file");
            }
            else
            {
                SqlConnection myConn = new SqlConnection();
                myConn.ConnectionString = ConfigurationManager.ConnectionStrings["myConn"].ToString();

                String filename = txtPath.Text;
                Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();
                Microsoft.Office.Interop.Excel.Workbook workBook = (Microsoft.Office.Interop.Excel.Workbook)app.Workbooks.Open(filename,
                                                      0,
                                                      true,
                                                      5,
                                                      "",
                                                      "",
                                                      true,
                                                      Microsoft.Office.Interop.Excel.XlPlatform.xlWindows,
                                                      "\t",
                                                      false,
                                                      false,
                                                      0,
                                                      true,
                                                      1,
                                                      0);
                Microsoft.Office.Interop.Excel.Worksheet workSheet = (Microsoft.Office.Interop.Excel.Worksheet)workBook.ActiveSheet;


                int index = 0;

                object rowIndex = 1;
                object colIndex3 = 3;
                object colIndex9 = 9;
                object colIndex12 = 12;
                object colIndex1 = 1;



                try
                {
                    while (((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex3]).Value2 != null)
                    {
                        myConn.Open();
                        rowIndex = 1 + index;
                        string col3 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex3]).Value2.ToString();
                        string col9 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex9]).Value2.ToString();
                        string col12 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex12]).Value2.ToString();
                        string col1 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex1]).Value2.ToString();

                        string insert = "INSERT INTO FAT_Table(Type,IPAddress,ComputerName,Owner)VALUES('" + col3 + "','" + col9 + "','" + col12 + "','" + col1 + "')";

                        SqlCommand cmd = new SqlCommand(insert, myConn);
                        SqlDataReader reader = cmd.ExecuteReader();


                        index++;

                        myConn.Close();
                        BindDataGrid();

                    }

                }
                catch (Exception ex)
                {
                    app.Quit();
                    Console.WriteLine(ex.Message);
                }
            }
        }

        private void BindDataGrid2()
        {
            SqlConnection myConn = new SqlConnection();
            myConn.ConnectionString = ConfigurationManager.ConnectionStrings["myConn"].ToString();

            myConn.Open();

            string strSQL = "SELECT * FROM IPScanning_Table ";
            SqlDataAdapter dataAdapter = new SqlDataAdapter(strSQL, myConn);
            SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
  
            DataTable table = new DataTable();
            dataAdapter.Fill(table);
            BindingSource.DataSource = table;
            dataGridView2.ReadOnly = true;
            dataGridView2.DataSource = BindingSource;

            myConn.Close();
        }

        private void btnBrowse2_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFD = new OpenFileDialog();

            openFD.CheckFileExists = true;
            openFD.InitialDirectory = "Desktop";
            openFD.Title = "Select a File";
            openFD.FileName = "";
            openFD.Multiselect = false;
            openFD.Filter = "All Files (*.*)|*.*|Excel Files (*.xls)|*.xls|CSV Files (*.csv*)|*.csv";

            if (openFD.ShowDialog() == DialogResult.OK)
            {
                this.txtPath2.Text = openFD.FileName;

            }
        }

        private void btnImport2_Click(object sender, EventArgs e)
        {
            if (txtPath2.Text == "")
            {
                MessageBox.Show("Please select a file");
            }
            else
            {
                SqlConnection myConn = new SqlConnection();
                myConn.ConnectionString = ConfigurationManager.ConnectionStrings["myConn"].ToString();

                String filename2 = txtPath2.Text;
                Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();
                Microsoft.Office.Interop.Excel.Workbook workBook = (Microsoft.Office.Interop.Excel.Workbook)app.Workbooks.Open(filename2,
                                                      0,
                                                      true,
                                                      5,
                                                      "",
                                                      "",
                                                      true,
                                                      Microsoft.Office.Interop.Excel.XlPlatform.xlWindows,
                                                      "\t",
                                                      false,
                                                      false,
                                                      0,
                                                      true,
                                                      1,
                                                      0);
                Microsoft.Office.Interop.Excel.Worksheet workSheet = (Microsoft.Office.Interop.Excel.Worksheet)workBook.ActiveSheet;


                int index = 0;

                object rowIndex = 1;
                object colIndex2 = 2;
                object colIndex1 = 1;
                object colIndex5 = 5;
                object colIndex4 = 4;



                try
                {
                    while (((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex2]).Value2 != null)
                    {
                        myConn.Open();
                        rowIndex = 1 + index;
                        string col2 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex2]).Value2.ToString();
                        string col1 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex1]).Value2.ToString();
                        string col5 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex5]).Value2.ToString();
                        string col4 = ((Microsoft.Office.Interop.Excel.Range)workSheet.Cells[rowIndex, colIndex4]).Value2.ToString();

                        string insert = "INSERT INTO IPScanning_Table(Status,IPAddress,ComputerName,OperatingSystem)VALUES('" + col2 + "','" + col1 + "','" + col5 + "','" + col4 + "')";

                        SqlCommand cmd = new SqlCommand(insert, myConn);
                        SqlDataReader reader = cmd.ExecuteReader();


                        index++;

                        myConn.Close();
                        BindDataGrid2();

                    }

                }
                catch (Exception ex)
                {
                    app.Quit();
                    Console.WriteLine(ex.Message);
                }
            }
        }

        
        

       
     

       

        
      
    }
}

Please help me.
Thank you in advance.

Well, is there a question. Where is that you are facing difficulty and what help do you want.

the problem is i have no idea how to do the comparison between both table. any suggestion ?

Compare between the two tables by Database engine using Outer join then the result would be shown in the Grid.

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