Question

我在backgroundworker上执行了一个非常长的代码，但是有时候我们遇到网络问题而且它显示了webexception，为了处理它我想在异常块中再次调用该函数，我尝试在同一个后台工作器上再次调用函数取消它，但似乎我做得不对，

请检查我的代码，它真的很长，所以我只是在这里发布必要的细节，如果不够，请提前对不起（在这种情况下让我知道）

  public static DataSet ds_input;
    private void btn_process_Click(object sender, EventArgs e)
    {
        //some code here to fetch data and call backgroundworker
        backgroundWorker1.RunWorkerAsync(ds);
    }

    private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
    {               
        //ds_input is a dataset with data in it
                e.Result = check_number(ds_input);
    }

    private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
    {
            int i = e.ProgressPercentage;
            int j = showProgress(i, Total_Record);
            lbl_counter.Text = "Processing " + Convert.ToString(i + 1) + " / " + Convert.ToString(Total_Record) + "  ";
    }

    private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
    {

            DataTable dt = e.Result as DataTable;
            Grid_records.DataSource = e.Result;
    }

    public void check_number(DataSet ds)
    {
        try
        {
            // logic here to perform execution
            //sometime it break due to internet connectivity 
            // i want to resume it in catch block 
        }
        catch (System.Net.WebException ex)
        {

            //how to run backgroundWorker1 here again 
            // i did this 
            backgroundWorker1.CancelAsync();
            backgroundWorker1.Dispose();
            backgroundWorker1.RunWorkerAsync(ds_input);
            // but it says -This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.
            //how to resume the function on same  backgroundWorker1
        }
        finally
        {
        }
    }
}

Answer 1

我会以不需要重新运行后台工作程序的方式调整执行逻辑，而是在结果不符合预期的情况下重新运行操作。也许是这样的：

public static DataSet ds_input;
    private void btn_process_Click(object sender, EventArgs e)
    {
        //some code here to fetch data and call backgroundworker
        backgroundWorker1.RunWorkerAsync(ds);
    }

    private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
    {               
        bool success = false;

        do
        {
            try
            {
                e.Result = check_number(ds_input);
                success = true;
            }
            catch (System.Net.WebException ex)
            {
               success = false;
            }

        }while(!success);
    }

    private void backgroundWorker1_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
    {
            int i = e.ProgressPercentage;
            int j = showProgress(i, Total_Record);
            lbl_counter.Text = "Processing " + Convert.ToString(i + 1) + " / " + Convert.ToString(Total_Record) + "  ";
    }

    private void backgroundWorker1_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
    {

            DataTable dt = e.Result as DataTable;
            Grid_records.DataSource = e.Result;
    }

    public DataTable check_number(DataSet ds)
    {
        // Do whatever is needed
    }
}

如果出现错误，如何在backgroundworker上再次调用函数

1 个答案: