A question about making a C# class persistent during a file load
- by Adam
Apologies for the indescriptive title, however it's the best I could think of for the moment.
Basically, I've written a singleton class that loads files into a database. These files are typically large, and take hours to process. What I am looking for is to make a method where I can have this class running, and be able to call methods from within it, even if it's calling class is shut down.
The singleton class is simple. It starts a thread that loads the file into the database, while having methods to report on the current status. In a nutshell it's al little like this:
public sealed class BulkFileLoader {
static BulkFileLoader instance = null;
int currentCount = 0;
BulkFileLoader()
public static BulkFileLoader Instance
{
// Instanciate the instance class if necessary, and return it
}
public void Go() {
// kick of 'ProcessFile' thread
}
public void GetCurrentCount() {
return currentCount;
}
private void ProcessFile() {
while (more rows in the import file) {
// insert the row into the database
currentCount++;
}
}
}
The idea is that you can get an instance of BulkFileLoader to execute, which will process a file to load, while at any time you can get realtime updates on the number of rows its done so far using the GetCurrentCount() method.
This works fine, except the calling class needs to stay open the whole time for the processing to continue. As soon as I stop the calling class, the BulkFileLoader instance is removed, and it stops processing the file. What I am after is a solution where it will continue to run independently, regardless of what happens to the calling class.
I then tried another approach. I created a simple console application that kicks off the BulkFileLoader, and then wrapped it around as a process. This fixes one problem, since now when I kick off the process, the file will continue to load even if I close the class that called the process. However, now the problem I have is that cannot get updates on the current count, since if I try and get the instance of BulkFileLoader (which, as mentioned before is a singleton), it creates a new instance, rather than returning the instance that is currently in the executing process. It would appear that singletons don't extend into the scope of other processes running on the machine.
In the end, I want to be able to kick off the BulkFileLoader, and at any time be able to find out how many rows it's processed. However, that is even if I close the application I used to start it.
Can anyone see a solution to my problem?
