private void button3_Click(object sender, EventArgs e)
        {

            try
            {
                Microsoft.Office.Interop.Excel.Application excel = new Microsoft.Office.Interop.Excel.Application();
                excel.Visible = true;
                Microsoft.Office.Interop.Excel.Workbook workbook = excel.Workbooks.Add(System.Reflection.Missing.Value);
                Microsoft.Office.Interop.Excel.Worksheet sheet1 = (Microsoft.Office.Interop.Excel.Worksheet)workbook.Sheets[1];
                int StartCol = 1;
                int StartRow = 1;
                int j = 0, i = 0;

                //Write Headers
                for (j = 0; j < dataGridView.Columns.Count; j++)
                {
                    Microsoft.Office.Interop.Excel.Range myRange = (Microsoft.Office.Interop.Excel.Range)sheet1.Cells[StartRow, StartCol + j];
                    myRange.Value2 = dataGridView.Columns[j].HeaderText;
                }

                StartRow++;

                //Write datagridview content
                for (i = 0; i < dataGridView.Rows.Count; i++)
                {
                    for (j = 0; j < dataGridView.Columns.Count; j++)
                    {
                        try
                        {
                            Microsoft.Office.Interop.Excel.Range myRange = (Microsoft.Office.Interop.Excel.Range)sheet1.Cells[StartRow + i, StartCol + j];
                            myRange.Value2 = dataGridView[j, i].Value == null ? "" : dataGridView[j, i].Value;
                        }
                        catch
                        {
                            ;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }

        }

        private void button5_Click(object sender, EventArgs e)
        {



        }