C#导出Excel

ExcelHelper：

    public class ExcelHelper
    {
        public static void Export(System.Data.DataTable dt, string filePath)
        {
            if (dt == null)
            {
                throw new Exception("数据表中无数据");
            }
            int eRowIndex = 1;
            int eColIndex = 1;
            int cols = dt.Columns.Count;
            int rows = dt.Rows.Count;
            Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.ApplicationClass();//.Application();//.ApplicationClass();
            Microsoft.Office.Interop.Excel.Workbook xlBook = xlApp.Workbooks.Add(true);
            try
            {
                //列名的处理
                for (int i = 0; i < cols; i++)
                {
                    xlApp.Cells[eRowIndex, eColIndex] = dt.Columns[i].ColumnName;
                    eColIndex++;
                }
                //列名加粗显示
                xlApp.get_Range(xlApp.Cells[eRowIndex, 1], xlApp.Cells[eRowIndex, cols]).Font.Bold = true;
                xlApp.get_Range(xlApp.Cells[eRowIndex, 1], xlApp.Cells[rows + 1, cols]).Font.Name = "Arial";
                xlApp.get_Range(xlApp.Cells[eRowIndex, 1], xlApp.Cells[rows + 1, cols]).Font.Size = "10";
                eRowIndex++;

                for (int i = 0; i < rows; i++)
                {
                    eColIndex = 1;
                    for (int j = 0; j < cols; j++)
                    {
                        xlApp.Cells[eRowIndex, eColIndex] = dt.Rows[i][j].ToString();
                        eColIndex++;
                    }
                    eRowIndex++;
                }
                //控制单元格中的内容。
                xlApp.Cells.EntireColumn.AutoFit();

                xlApp.DisplayAlerts = false;
                xlBook.SaveCopyAs(filePath);
                xlApp.Workbooks.Close();

            }
            catch
            {
                throw;
            }
            finally
            {
                xlApp.Quit();
                //杀掉Excel进程。
                GC.Collect();
            }
        }

        /// <summary>
        /// 将datatable导出到Excel
        /// </summary>
        /// <param name="dt"></param>
        public static void ExportToExcel(DataTable dt)
        {
            SaveFileDialog sfd = new SaveFileDialog();
            sfd.Filter = "xlsx files (*.xlsx)|*.xlsx|All Files(*.*)|*.*";
            sfd.ShowDialog();
            string filepath = sfd.FileName;
            if (filepath == "" || filepath.Substring(filepath.LastIndexOf('.') + 1).ToLower() != "xlsx")
            {
                return;
            }
            else
            {
                try
                {
                    ExcelHelper.Export(dt, filepath);
                    MessageBox.Show("导出成功！", "提示");
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }
    }

需要：

导入Microsoft.Office.Interop.Excel，并且其Embed Interop Types属性设置为false，否则可能引发“Interop type 'Microsoft.Office.Interop.Excel.ApplicationClass' cannot be embedded”错误。