BulkCopy.WriteToServerAsync() Not Working Importing Records

asynchronous c# sqlbulkcopy

Question

I wrote a routine to bulk import records. It is not working and I think the problem is that I don't have any kind of await in here but I don't know how or where to put it in. Due to the nature of my project, I don't want the method to be an async method. I am just using async to notify of updates.

    public int LoadTempFile(string fn, string tableName)
    {
        int retVal = 1;
        // loads a CSV file into a temporary file of the same structure
        StatusWindow sw = new StatusWindow("Loading Temp Files");
        sw.Show();

        try
        {
            string cs = GetConnectionString() + ";Asynchronous Processing=true;"; 
            SqlConnection cxs = new SqlConnection(cs);
            SqlCommand cmd = new SqlCommand("Truncate table " + tableName, cxs);
            cxs.Open();
            cmd.ExecuteNonQuery();
            cmd.CommandTimeout = 640;
            cxs.Close();

            using (SqlBulkCopy copy = new SqlBulkCopy(cs))
            {
                using (StreamReader file = new StreamReader(fn))
                {
                    CsvReader csv = new CsvReader(file, true);
                    copy.DestinationTableName = tableName;
                    copy.BulkCopyTimeout = 1640;
                    copy.NotifyAfter = 100;
                    copy.SqlRowsCopied += (sender, eventArgs) =>
                     {
                        sw.Update(eventArgs.RowsCopied.ToString() + " Records Copied");
                    };


                    try
                    {
                       copy.WriteToServerAsync(csv);
                    }
                    catch (SqlException ex)
                    {
                        MessageBox.Show("SQL Error Importing " + fn + Environment.NewLine + ex.Message);
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("Error Importing " + fn + Environment.NewLine + ex.Message);
                    }

                }
            }
        }
        catch (Exception e)
        {
            MessageBox.Show("Error In Temp Files " + fn + Environment.NewLine + e.ToString());
            retVal = 0;
        }
        finally
        { sw.Close(); }
        return (retVal);
    }

I would appreciate any help or input. Also, comments on my coding style or things like that are welcome, too.

1
2
8/22/2017 3:19:23 PM

Accepted Answer

You are correct, the reason this code does not work is that you never await the call to copy.WriteToServerAsync(csv); The method returns you a Task object

I don't want the method to be an async method. I am just using async to notify of updates.

Getting notifications is not conditioned upon using async version of the method. In fact, Microsoft's own example for SqlRowsCopied uses a synchronous version, i.e. copy.WriteToServer(...).

Using async wouldn't help getting UI notifications unless you go async all the way. See this Q&A for more information.

2
8/22/2017 3:22:12 PM


Related Questions





Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow
Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow