取消多线程任务，包括运行 .dll

Question

我有 2 个同步启动的不同任务。其中之一是我调用 .dll 来创建 COM 对象（写入 Excel 文件）的方法。当我终止这两个任务时，Excel 文件仍在使用中，所以我无法删除它。这就是我调用这两个任务的方式：

private CancellationTokenSource cancel_1 = new CancellationTokenSource();
private CancellationTokenSource cancel_2 = new CancellationTokenSource();

    private void Form1_Load(object sender, System.EventArgs e)
    {
        cancel_1 = new CancellationTokenSource();
        var task_1 = Task.Factory.StartNew(() => DoWork1(), cancel_1.Token);

        //2nd task
        cancel_2 = new CancellationTokenSource();
        var task_2 = Task.Factory.StartNew(() => DoExcelWork(), cancel_2.Token);
    }

然后我尝试取消 form_closing 中的两个任务：

private void Form1_FormClosing(object sender, System.Windows.Forms.FormClosingEventArgs e)
{
   //Cancel all running processes
   cancel_1.Cancel();
   cancel_2.Cancel();

   // I've also set a variable for check if Task_2 is running and try to clear COM 
   // object with clearing GC(), but It's not working
   if (excel_running)
   {
       GC.Collect();
       GC.WaitForPendingFinalizers();
       GC.Collect();
       GC.WaitForPendingFinalizers();

       string filename = Environment.GetFolderPath(Environment.SpecialFolder.Desktop).ToString() + @"\" + "sample.xlsx";
       File.Delete(filename)

   }
}

但是，这并不是终止由 .dll 启动的写入 Excel 文件的进程。我注意到后台的运行进程是 "COM surrogate"，所以如您所见，我尝试在 2 个周期内清理 GC()，但文件仍在使用中。

我的线程方法代码是这样的：

public void DoExcelWork()
{
    try
    {
        using (var con = new OracleConnection(conn_string))
        {
            con.Open();

            using (OracleCommand cmd = new OracleCommand("myprocedure"))
            {
                cmd.Connection = con;
                cmd.CommandType = CommandType.StoredProcedure;

                cmd.Parameters.Add(new OracleParameter("par1", OracleDbType.NVarchar2) { Direction = ParameterDirection.Input, Value = SQL_string });

                cmd.Parameters.Add(new OracleParameter("result", OracleDbType.RefCursor)).Direction = ParameterDirection.Output;

                //Here is the call of .dll             
                Export export_xml = new Export();
                export_xml.Save_to_Excel(cmd);

                excel_running = false;

                if (cancel_2.IsCancellationRequested)
                {
                   cmd.Cancel();
                   return;
                }

    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message + "in " + ex.StackTrace);
    }
}

我的问题是 - 如何正确取消后台进程，这样它甚至会关闭运行 .dll？

Answer 1

已解决。我不得不 re-organize DoExcelWork() 方法来接受 CancellationToken 的附加参数，然后在方法中调用 "token.IsCancellationRequested" 关闭所有正在创建 Excel 文件的对象.

取消多线程任务，包括运行 .dll

Cancel multi-threading Tasks including running .dll

c#

com

excel

asynchronous

task

取消多线程任务，包括 运行 .dll

Cancel multi-threading Tasks including running .dll

c#

com

excel

asynchronous

task

取消多线程任务，包括运行 .dll