c# - 用多线程写入excel文件

Question

我正在尝试将数据表写入具有大量记录的 excel。我正在尝试使用分而治之的策略来实现，其中每个线程都被分配写入各自的 excelworkbook 工作表。但我得到的文件是只读的，单击“确定”覆盖文件。

class Program
{
    int processorCount = 2;
    static volatile bool processing = true;
    DataTable employeeTable = new DataTable("Employee");
    ManualResetEvent mre = new ManualResetEvent(false);

    AutoResetEvent ar = new AutoResetEvent(true);
    int record_count;
    static void Main(string[] args)
    {
        Program p = new Program();

        //Create an Emplyee DataTable

        p.employeeTable.Columns.Add("Employee ID");
        p.employeeTable.Columns.Add("Employee Name");
        for (int i = 0; i <= 2; i++)
        {
            p.employeeTable.Rows.Add(i.ToString(), "ABC");
        }
        p.record_count = p.employeeTable.Rows.Count / p.processorCount;


        Excel.Application excelApp = new Excel.Application();

        //Create an Excel workbook instance and open it from the predefined location
         Excel.Workbook excelWorkBook1 = excelApp.Workbooks.Open(@"F:\Org.xlsx");

        Thread[] threads = new Thread[3];
        for (int i = 0; i < 3; i++)
        {

            //  p.ExportDataSetToExcel(i);
            ParameterizedThreadStart ps = new ParameterizedThreadStart(p.ExportDataSetToExcel);
            threads[i] = new Thread(ps);
            threads[i].Start(new Custom() { sheetNo = i, excelWorkBook = excelWorkBook1 });
        }

        for (int j = 0; j < 3; j++)
        {
            threads[j].Join();
        }

        Console.WriteLine("Succeess");

        Console.ReadKey();



    }

    private void ExportDataSetToExcel(object sheet1)
    {

        lock (this)
        {
            bool found = false;
            Excel.Worksheet excelWorkSheet;

            int sheetNo = ((Custom)sheet1).sheetNo;
            Excel.Workbook excelWorkBook = ((Custom)sheet1).excelWorkBook;
            excelWorkSheet = (excelWorkBook).Sheets["Sheet" + ((int)sheetNo + 1).ToString()];

            for (int i = 1; i < employeeTable.Columns.Count + 1; i++)
            {
                excelWorkSheet.Cells[1, i] = employeeTable.Columns[i - 1].ColumnName;
            }

            int baseIndex = (int)sheetNo * record_count;
            for (int j = baseIndex; j < baseIndex + record_count; j++)
            {
                for (int k = 0; k < employeeTable.Columns.Count; k++)
                {
                    excelWorkSheet.Cells[j + 2, k + 1] = employeeTable.Rows[j].ItemArray[k].ToString();
                }
            }

            Console.WriteLine(sheetNo.ToString());
            Console.WriteLine("\n");

            (excelWorkBook).Save();
            (excelWorkBook).Close();
        }
    }



}**strong text**
  public class  Custom
  {
      public int sheetNo;
      public Excel.Workbook excelWorkBook;
  } 

Answer 1

遗憾的是，Excel 并未设计为多线程。但我建议的是，您编写的内容会更有效。逐个单元地写入是减速的最大部分。

消除这两个因素(组织数据和写入数据)将减少实际写入时间，使其可能消除并发写入的需要。

我有一个旧的 VSTO 项目，我必须从数据库中写入数据集，然后将数据提取到二维数组中，然后将整个数组写入工作表上的一个区域，如下所示:

Microsoft.Office.Tools.Excel.Worksheet TheSheet;


private void PublishToSheet( int totalRows, int maxColumns, ref string[,] OutputArray )
{
    Excel.Range Range = TheSheet.Range["A1", TheSheet.Cells[totalRows, maxColumns]];
    Range.NumberFormat = "@";
    Range.Value2 = OutputArray;

    LastRow = totalRows;
    LastColumn = maxColumns;

}