Excel导入和导出

  try
            {   
                MES.BLL.extend.TEST_PROJECT_EXTEND MaterialBLL = new MES.BLL.extend.TEST_PROJECT_EXTEND();
                result = MaterialBLL.QueryAllocationproduct(identificationproduct);
                string[] Cellnames = new string[] { "产品名称", "产品型号", "类型", "版本号", "生产资料名称", "上传时间" };
                AllocationList = MaterialBLL.DataExcelToList(result.Tables[0]);
                DataTable dt = ExcelHelper.ListToDataTable(AllocationList);
                ExcelHelper.ExportExcel(dt, Cellnames);
            }

 public static DataTable ListToDataTable<T>(List<T> entitys)
        {

            //检查实体集合不能为空
            if (entitys == null || entitys.Count < 1)
            {
                return new DataTable();
            }

            //取出第一个实体的所有Propertie
            Type entityType = entitys[0].GetType();
            PropertyInfo[] entityProperties = entityType.GetProperties();

            //生成DataTable的structure
            //生产代码中，应将生成的DataTable结构Cache起来，此处略
            DataTable dt = new DataTable("dt");
            for (int i = 0; i < entityProperties.Length; i++)
            {
                //dt.Columns.Add(entityProperties[i].Name, entityProperties[i].PropertyType);
                dt.Columns.Add(entityProperties[i].Name);
            }

            //将所有entity添加到DataTable中
            foreach (object entity in entitys)
            {
                //检查所有的的实体都为同一类型
                if (entity.GetType() != entityType)
                {
                    throw new Exception("要转换的集合元素类型不一致");
                }
                object[] entityValues = new object[entityProperties.Length];
                for (int i = 0; i < entityProperties.Length; i++)
                {
                    entityValues[i] = entityProperties[i].GetValue(entity, null);

                }
                dt.Rows.Add(entityValues);
            }
            return dt;
        }

 //导出
        public static void ExportExcel(DataTable dt, string[] Cellnames)
        {
            if (dt != null)
            {
                Microsoft.Office.Interop.Excel.Application excel = new Microsoft.Office.Interop.Excel.Application();

                if (excel == null)
                {
                    return;
                }

                //设置为不可见，操作在后台执行，为 true 的话会打开 Excel
                excel.Visible = false;

                //打开时设置为全屏显式
                //excel.DisplayFullScreen = true;

                //初始化工作簿
                Microsoft.Office.Interop.Excel.Workbooks workbooks = excel.Workbooks;

                //新增加一个工作簿，Add（）方法也可以直接传入参数 true
                Microsoft.Office.Interop.Excel.Workbook workbook = workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);
                //同样是新增一个工作簿，但是会弹出保存对话框
                //Microsoft.Office.Interop.Excel.Workbook workbook = excel.Application.Workbooks.Add(true);

                //新增加一个 Excel 表(sheet)
                Microsoft.Office.Interop.Excel.Worksheet worksheet = (Microsoft.Office.Interop.Excel.Worksheet)workbook.Worksheets[1];

                //设置表的名称
                worksheet.Name = dt.TableName;
                try
                {
                    //创建一个单元格
                    Microsoft.Office.Interop.Excel.Range range;

                    int rowIndex = 1;       //行的起始下标为 1
                    int colIndex = 1;       //列的起始下标为 1
                                            // worksheet.Cells[1, 1] = "列名1";
                                            // worksheet.Cells[1, 2] = "列名2";
                    for (int i = 0; i < Cellnames.Length; i++)
                    {
                        worksheet.Cells[rowIndex, colIndex + i] = Cellnames[i];
                    }

                    //设置列名
                    for (int i = 0; i < dt.Columns.Count; i++)
                    {
                        //设置第一行，即列名
                        //worksheet.Cells[rowIndex, colIndex + i] = dt.Columns[i].ColumnName;

                        //获取第一行的每个单元格
                        range = worksheet.Cells[rowIndex, colIndex + i];

                        //设置单元格的内部颜色
                        range.Interior.ColorIndex = 33;

                        //字体加粗
                        range.Font.Bold = true;

                        //设置为黑色
                        range.Font.Color = 0;

                        //设置为宋体
                        range.Font.Name = "Arial";

                        //设置字体大小
                        range.Font.Size = 12;

                        //水平居中
                        range.HorizontalAlignment = Microsoft.Office.Interop.Excel.XlHAlign.xlHAlignCenter;

                        //垂直居中
                        range.VerticalAlignment = Microsoft.Office.Interop.Excel.XlVAlign.xlVAlignCenter;
                    }

                    //跳过第一行，第一行写入了列名
                    rowIndex++;

                    //写入数据
                    for (int i = 0; i < dt.Rows.Count; i++)
                    {
                        for (int j = 0; j < dt.Columns.Count; j++)
                        {
                            worksheet.Cells[rowIndex + i, colIndex + j] = dt.Rows[i][j].ToString();
                        }
                    }

                    //设置所有列宽为自动列宽
                    //worksheet.Columns.AutoFit();

                    //设置所有单元格列宽为自动列宽
                    worksheet.Cells.Columns.AutoFit();
                    //worksheet.Cells.EntireColumn.AutoFit();

                    //是否提示，如果想删除某个sheet页，首先要将此项设为fasle。
                    excel.DisplayAlerts = false;

                    //保存写入的数据，这里还没有保存到磁盘
                    workbook.Saved = true;

                    //设置导出文件路径
                    //string path = HttpContext.Current.Server.MapPath("Export/");
                    string path = "D:\debugMES\API\WebAPIMes\Export\";
                     //设置新建文件路径及名称
                     string savePath = path + DateTime.Now.ToString("yyyy-MM-dd-HH-mm-ss") + ".xlsx";

                    //创建文件
                    FileStream file = new FileStream(savePath, FileMode.CreateNew);

                    //关闭释放流，不然没办法写入数据
                    file.Close();
                    file.Dispose();

                    //保存到指定的路径
                    workbook.SaveCopyAs(savePath);

                    //还可以加入以下方法输出到浏览器下载
                   FileInfo fileInfo = new FileInfo(savePath);
                    OutputClient(fileInfo);
                }
                catch (Exception ex)
                {

                }
                finally
                {
                    workbook.Close(false, Type.Missing, Type.Missing);
                    workbooks.Close();

                    //关闭退出
                    excel.Quit();

                    //释放 COM 对象
                    Marshal.ReleaseComObject(worksheet);
                    Marshal.ReleaseComObject(workbook);
                    Marshal.ReleaseComObject(workbooks);
                    Marshal.ReleaseComObject(excel);

                    worksheet = null;
                    workbook = null;
                    workbooks = null;
                    excel = null;

                    GC.Collect();
                }
            }
        }

 public static void OutputClient(FileInfo file)
        {
            HttpContext.Current.Response.Buffer = true;

            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.ClearHeaders();
            HttpContext.Current.Response.ClearContent();

            HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";

            //导出到 .xlsx 格式不能用时，可以试试这个
            //HttpContext.Current.Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";

            HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}.xlsx", DateTime.Now.ToString("yyyy-MM-dd-HH-mm")));

            HttpContext.Current.Response.Charset = "GB2312";
            HttpContext.Current.Response.ContentEncoding = Encoding.GetEncoding("GB2312");

            HttpContext.Current.Response.AddHeader("Content-Length", file.Length.ToString());

            HttpContext.Current.Response.WriteFile(file.FullName);
            HttpContext.Current.Response.Flush();

            HttpContext.Current.Response.Close();
        }

 System.Data.DataTable GetDataFromExcelByCom(string[] Cellnames, bool hasTitle = false )
        {
            OpenFileDialog openFile = new OpenFileDialog();
            openFile.Filter = "Excel(*.xlsx)|*.xlsx|Excel(*.xls)|*.xls";
            openFile.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            openFile.Multiselect = false;
            if (openFile.ShowDialog() == DialogResult.Cancel) return null;
            var excelFilePath = openFile.FileName;

            Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();
            Microsoft.Office.Interop.Excel.Sheets sheets;
            object oMissiong = System.Reflection.Missing.Value;
            Microsoft.Office.Interop.Excel.Workbook workbook = null;
            System.Data.DataTable dt = new System.Data.DataTable();

            try
            {
                if (app == null) return null;
                workbook = app.Workbooks.Open(excelFilePath, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong,
                  oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong);
                sheets = workbook.Worksheets;

                //将数据读入到DataTable中
                Microsoft.Office.Interop.Excel.Worksheet worksheet = (Microsoft.Office.Interop.Excel.Worksheet)sheets.get_Item(1);//读取第一张表 
                if (worksheet == null) return null;

                int iRowCount = worksheet.UsedRange.Rows.Count;
                int iColCount = worksheet.UsedRange.Columns.Count;
                //生成列头
                for (int i = 0; i < iColCount; i++)
                {
                    //var name = "column" + i;
                    var name = Cellnames[i];
                    if (hasTitle)
                    {
                        var txt = ((Microsoft.Office.Interop.Excel.Range)worksheet.Cells[1, i + 1]).Text.ToString();
                        if (!string.IsNullOrWhiteSpace(txt)) name = txt;
                    }
                    while (dt.Columns.Contains(name)) name = name + "_1";//重复行名称会报错。
                    dt.Columns.Add(new DataColumn(name, typeof(string)));
                }
                //生成行数据
                Microsoft.Office.Interop.Excel.Range range;
                int rowIdx = hasTitle ? 2 : 1;
                for (int iRow = rowIdx; iRow <= iRowCount; iRow++)
                {
                    DataRow dr = dt.NewRow();
                    for (int iCol = 1; iCol <= iColCount; iCol++)
                    {
                        range = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[iRow, iCol];
                        dr[iCol - 1] = (range.Value2 == null) ? "" : range.Text.ToString();
                    }
                    dt.Rows.Add(dr);
                }
                dt1 = dt;
                dataGridView1.DataSource = dt;
                return dt;
            }
            catch { return null; }
            finally
            {
                workbook.Close(false, oMissiong, oMissiong);
                System.Runtime.InteropServices.Marshal.ReleaseComObject(workbook);
                workbook = null;
                app.Workbooks.Close();
                app.Quit();
                System.Runtime.InteropServices.Marshal.ReleaseComObject(app);
                app = null;
            }
        }