Introduction to various export methods in C#

This article mainly introduces the relevant knowledge of various export methods in C#, which has a good reference value. Let’s take a look at it with the editor

The first one: to use Microsoft.Office.Interop.Excel.dll

First you need to Install office excel, then find the Microsoft.Office.Interop.Excel.dll component and add it to Reference.

public void ExportExcel(DataTable dt)
    {
      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

          //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/");

          //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 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();
    }

The performance of the first method is really unflattering, and it has too many limitations. First, you must install office (if it is not on your computer), and you need to specify the path to save the file when exporting. It can also be output to the browser for download, of course provided that the written data has been saved.

Second type: Use Aspose.Cells.dll

This Aspose.Cells is a tool for exporting Excel launched by Aspose Company Control does not depend on Office or commercial software, and is free of charge.

public void ExportExcel(DataTable dt)
    {
      try
      {
        //获取指定虚拟路径的物理路径
        string path = HttpContext.Current.Server.MapPath("DLL/") + "License.lic";

        //读取 License 文件
        Stream stream = (Stream)File.OpenRead(path);

        //注册 License
        Aspose.Cells.License li = new Aspose.Cells.License();
        li.SetLicense(stream);

        //创建一个工作簿
        Aspose.Cells.Workbook workbook = new Aspose.Cells.Workbook();

        //创建一个 sheet 表
        Aspose.Cells.Worksheet worksheet = workbook.Worksheets[0];

        //设置 sheet 表名称
        worksheet.Name = dt.TableName;

        Aspose.Cells.Cell cell;

        int rowIndex = 0;  //行的起始下标为 0
        int colIndex = 0;  //列的起始下标为 0

        //设置列名
        for (int i = 0; i < dt.Columns.Count; i++)
        {
          //获取第一行的每个单元格
          cell = worksheet.Cells[rowIndex, colIndex + i];

          //设置列名
          cell.PutValue(dt.Columns[i].ColumnName);

          //设置字体
          cell.Style.Font.Name = "Arial";

          //设置字体加粗
          cell.Style.Font.IsBold = true;

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

          //设置字体颜色
          cell.Style.Font.Color = System.Drawing.Color.Black;

          //设置背景色
          cell.Style.BackgroundColor = System.Drawing.Color.LightGreen;
        }

        //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++)
          {
            cell = worksheet.Cells[rowIndex + i, colIndex + j];

            cell.PutValue(dt.Rows[i][j]);
          }
        }

        //自动列宽
        worksheet.AutoFitColumns();

        //设置导出文件路径
        path = HttpContext.Current.Server.MapPath("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();

        //保存至指定路径
        workbook.Save(savePath);

        //或者使用下面的方法，输出到浏览器下载。
        //byte[] bytes = workbook.SaveToStream().ToArray();
        //OutputClient(bytes);

        worksheet = null;
        workbook = null;
      }
      catch(Exception ex)
      {
      }
    }
public void OutputClient(byte[] bytes)
    {
      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";
      HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}.xls", DateTime.Now.ToString("yyyy-MM-dd-HH-mm")));

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

      HttpContext.Current.Response.BinaryWrite(bytes);
      HttpContext.Current.Response.Flush();
      HttpContext.Current.Response.Close();
    }

The second method has good performance and is not complicated to operate. You can set the path to save the file when exporting, and you can also save it as a stream and output it to the browser for download.

Third option: Microsoft.Jet.OLEDB

This method of operating Excel is similar to operating a database. Let's first introduce the connectionString:

// Excel 2003 版本连接字符串
string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:/xxx.xls;Extended Properties='Excel 8.0;HDR=Yes;IMEX=2;'";
// Excel 2007 以上版本连接字符串
string strConn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:/xxx.xlsx;Extended Properties='Excel 12.0;HDR=Yes;IMEX=2;'";

Provider:DriverProgram name

Data Source:Specify the path to the Excel file

Extended Properties: Excel 8.0 is for Excel 2000 and above; Excel 12.0 is for Excel 2007 and above.

HDR: Yes means that the first row contains column names, and the first row is not included when calculating the number of rows. NO is the complete opposite.

IMEX: 0 writing mode; 1 reading mode; 2 reading and writing mode. If the error is "Cannot modify the design of table sheet1. It is in a read-only database", then remove this and the problem will be solved.

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