使用BackgroundWorker在WPF中使用datagrid中的多個導入按鈕導入Mutiple記錄

Question

要求：允許用戶導入多個記錄並允許單擊多個導入按鈕（在DATAGRID中）。

當用戶單擊單個導入按鈕時，我能夠處理導入按鈕功能，但是如果用戶單擊另一個導入按鈕，則無法導入。

下面是我的相同代碼。

 BackgroundWorker bgWorkerUpdate = new BackgroundWorker();

 // Constructor
 public ImportedKeywords()
 {
      bgWorkerUpdate.DoWork += new DoWorkEventHandler(bgWorkerUpdateDoWork);
      bgWorkerUpdate.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgWorkerUpdate_Completed);
 }

 private void Import_Click(object sender, RoutedEventArgs e)
 {
       if (!bgWorkerUpdate.IsBusy) bgWorkerUpdate.RunWorkerAsync(objSearchRequest);
       else
       {
           bgWorkerUpdate = new BackgroundWorker();
           bgWorkerUpdate.RunWorkerAsync(objSearchRequest);
       }
 }


     public void bgWorkerUpdateDoWork(object sender, DoWorkEventArgs e)
        {
            SearchRequest objSearchRequest = (SearchRequest)e.Argument;//txtUserName.Text;
            importCount = new AdvancedSearching().SearchContent(objSearchRequest, totalRecords, totalRecordsImported, recordsToImport, keywordID, selectedPriority);
        }


  void bgWorkerUpdate_Completed(object sender, RunWorkerCompletedEventArgs e)
        {
            imgLoading.Visibility = System.Windows.Visibility.Hidden;
            if (importCount == 0)
            {
                lblMessage.Content = "No record found to import.";
                lblMessage.Foreground = Brushes.DarkRed;
            }
            else
            {

                lblMessage.Content = importCount + " Record(s) imported successfully.";
                lblMessage.Foreground = Brushes.DarkGreen;
                BindList(Convert.ToInt32(tbStartPage.Text), txtSearch.Text, "test");
                MaintainSortingWithPaging(Convert.ToInt32(tbStartPage.Text));
            }
            HideLoading();
        }

Answer 1

創建BackgroundWorker的新實例時，必須再次訂閱DoWork和RunWorkerCompleted事件。 否則，它在運行時不會做任何事情。

if (!bgWorkerUpdate.IsBusy)
    bgWorkerUpdate.RunWorkerAsync(objSearchRequest);
else
{
    bgWorkerUpdate = new BackgroundWorker();
    bgWorkerUpdate.DoWork += bgWorkerUpdateDoWork;
    bgWorkerUpdate.RunWorkerCompleted+= bgWorkerUpdate_Completed;
    bgWorkerUpdate.RunWorkerAsync(objSearchRequest);
}

但是，如果您只想在舊線程仍在運行的情況下，在一個新線程中運行每個作業，那么您也許可以研究其他結構，例如Task.Run 。