C#

public Boolean LoadData()
        {
            Boolean bComplete = false;
            Int32 nTotalData = 10000;
            this.tasks = new Task[nTotalData];
            DateTime dtStartTime = DateTime.Now;

            ProcessingBarsCS.StartTime();
            var parent = Task.Factory.StartNew(() =>
            {
                dtStartTime = DateTime.Now;

                for (Int32 nData = 0; nData < nTotalSymbols; nData++)
                {
                    bComplete = GetData_Task(nData, dtStartTime, nTotalData);
                }
            });
            parent.Wait();
            ProcessingBarsCS.StopTime();

            return bComplete;
        }

        Boolean GetData_Task(Int32 nData, DateTime  dtStartTime, Int32 nTotalData)
        {
            DataCS dataCS = new DataCS();
            tasks[nData] = Task.Factory.StartNew(() =>
            {
                nData = dataCS.Data();
            })
                .ContinueWith(antecendent => ProcessingData(nData));

            // *****
            tasks[nData].Wait();

            // Wait for all task to finish calculations
            try
            {
                Task.WaitAll(tasks);
                SetData_ElapsedTime(dtStartTime, nTotalData);
            }
            catch { }

            return true;
        }

Microsoft.Synchronization.MetadataStorage.MetadataStorageEngineException: Fehler bei einem Speichermodulvorgang. Fehlercode: 25039 (HRESULT = 0x80004005, Quellen-IID = {0C733A7A-2A1C-11CE-ADE5-00AA0044773D}, Parameter=(0, 0, 0, H:\filesync.metadata, , , )).
---> System.Runtime.InteropServices.COMException: Fehler bei einem Speichermodulvorgang. Fehlercode: 25039 (HRESULT = 0x80004005, Quellen-IID = {0C733A7A-2A1C-11CE-ADE5-00AA0044773D}, Parameter=(0, 0, 0, (sourceNetworkDirectory)\filesync.metadata, , , )).

public partial class Form1 : Form
  {
      public const int GW_HWNDNEXT = 2; // The next window is below the specified window
      public const int GW_HWNDPREV = 3; // The previous window is above

      [DllImport("user32.dll")]
      static extern IntPtr GetTopWindow(IntPtr hWnd);

      [DllImport("user32.dll")]
      [return: MarshalAs(UnmanagedType.Bool)]
      static extern bool IsWindowVisible(IntPtr hWnd);

      [DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint = "GetWindow", SetLastError = true)]
      public static extern IntPtr GetNextWindow(IntPtr hwnd, [MarshalAs(UnmanagedType.U4)] int wFlag);

      public Form1()
      {
          InitializeComponent();

          //how to get the return value from here???
      }

      public static Form GetTopMostWindow(IntPtr hWnd_mainFrm)
      {
          Form frm = null;

          IntPtr hwnd = GetTopWindow((IntPtr)null);
          if (hwnd != IntPtr.Zero)
          {
              while ((!IsWindowVisible(hwnd) || frm == null) && hwnd != hWnd_mainFrm)
              {
                  // Get next window under the current handler
                  hwnd = GetNextWindow(hwnd, GW_HWNDNEXT);

                  try
                  {
                      frm = (Form)Form.FromHandle(hwnd);
                  }
                  catch
                  {
                      // Weird behaviour: In some cases, trying to cast to a Form a handle of an object
                      // that isn't a form will just return null. In other cases, will throw an exception.
                  }
              }
          }

          return frm;
      }



  }