Change exp rate forge rate

   private void button_Click(object sender, EventArgs e)
        {

           
            openFileDialog1.ShowDialog();
            string _str = openFileDialog1.FileName ;
            if (_str != "")
            {
                using (FileStream fs = new FileStream(_str, FileMode.Open, FileAccess.Read))
                {
                    using (DataTable dt = new DataTable())
                    {
                        dt.Columns.Add("No", typeof(int));
                        dt.Columns.Add("Pos", typeof(long));
                        dt.Columns.Add("value", typeof(string));
                        using (BinaryReader br = new BinaryReader(fs))
                        {
                            int _no = 1;
                            int bspos = 0;
                            br.BaseStream.Position = bspos;
                            while (br.BaseStream.Position < br.BaseStream.Length - bspos)
                            {
                               
                                    long _pos = br.BaseStream.Position;
                                    int _val1 = br.ReadInt32();
                                    dt.Rows.Add(_no, _pos,Convert.ToString( _val1));
                                    _no += 1;
                                

                            }
                        }
                       
                        dataGridView1.DataSource = dt;

                    }
                }
            }
           
        }