private void btnCriarArquivoExcel_Click(object sender, EventArgs e)
        {
            try
            {
                Excel.Application xlApp;
                Excel.Workbook xlWorkBook;
                Excel.Worksheet xlWorkSheet;
                object misValue = System.Reflection.Missing.Value;

                xlApp = new Excel.Application();
                xlWorkBook = xlApp.Workbooks.Add(misValue);

                xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
                xlWorkSheet.Cells[1, 1] = "http://www.macoratti.net";

                xlWorkBook.SaveAs(txtArquivoExcel.Text, Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue,
 Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
                xlWorkBook.Close(true, misValue, misValue);
                xlApp.Quit();

                liberarObjetos(xlWorkSheet);
                liberarObjetos(xlWorkBook);
                liberarObjetos(xlApp);

                MessageBox.Show("O arquivo Excel foi criado com sucesso. Você pode encontrá-lo em : " + txtArquivoExcel.Text);
            }
            catch (Exception ex)
            {
                MessageBox.Show("Erro : " + ex.Message);
            }
        }

       private void liberarObjetos(object obj)
        {
            try
            {
                System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
                obj = null;
            }
            catch (Exception ex)
            {
                obj = null;
                MessageBox.Show("Ocorreu um erro durante a liberação do objeto " + ex.ToString());
            }
            finally
            {
                GC.Collect();
            }
        }

private void lerExcel()
{

            string connectionString = String.Format(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0}; 
Extended Properties=""Excel 8.0;HDR=NO;IMEX=1;""", txtArquivoExcel.Text);

            string query = String.Format("select * from [{0}$]", "Plan1");
            OleDbDataAdapter dataAdapter = new OleDbDataAdapter(query, connectionString);
            DataSet dataSet = new DataSet();
            dataAdapter.Fill(dataSet);
            gdvExcel.DataSource = dataSet.Tables[0];
}