Sometimes you have a problem where two incompatable system, (such as a POS/ Cash Register) , needs to integrate with a new software systems (such as a new website) data. The issue is that the POS system is the Master of Inventroy (MOI) and needs to update the websites database peridocally to sync up the inventories.

There are three ways to accomplish this:

1) Create a outbound xml channel to your database that updates the inventory periodacally. Problem: expensize as you would need a Biztalk server or something of the sort and complex as you will have to define and map the outbound and inbound structure
2) Have the admin mannually update the products in stock.Problem: Inpracticall even if you created a upload page the  user would have to spend hours a day entering and verifing the data.
3) Create a multithreading kernel that polls a specifc location and imports the data based on a export file.

Most Inventory control systems have a export functionality, wither it is in XML or some propietary system. You simply need to create a kernal that will poll a particular location and pull in the data as soon as the Inventory control system spits it out.

Here the outline of what we want to accomplish:
1. A Multi-Threading
2.  Some Feebback and Logging
3. A Folder location where the export file will be continously polled.

Program
Start by opening Visual studio and create a Windows application in C#.

Lets start by adding the basic elements that will contrust our kernel:

1. Add a Start and Stop button and a browse button
2. Add a text box of the File Directory to be inserted
3. Add a Multiline TextBox that will display your messages
4. Drop a OpenFileDialog Control
5. Drop a Worker thread

Your form should look something like this:

Coding

Double click the browse button and use the OpenFiledialog control which I named fbd to show and grab a file location. This will be the location were we will poll for a export file.

Sample Code
{
fbd.ShowDialog();
txtFolderLocation.Text = fbd.SelectedPath;
}
 Next we will look at the start and stop buttonThinking about what we want to do: First the Start and Stop button we be associated with the ThreadWorker component that previously dropped on the form. Second we want to report all messages to the large Text box.
 

Lets look a the properties of the Thread are:

The only property that we are conserned with is the WorkerSupportsCancellation. We want to be able to stop the Thread gracefully, so this property needs to be set to true.Now lets look at the events of the Thread

The only two things we are concerned win are the DoWork and the RunWorkerCompleted Event. The DoWork is is the function that is going to be called when you start the thread and RunWorkedCompleted is the event called when you push the stop button. Double click on these event to create the Events.DoWork The function of this event is to poll the folder selected previously the code is simple:

Code:

private void thread1_DoWork(object sender, DoWorkEventArgs e)
{
while (!thread1.CancellationPending)
{
if (File.Exists(path))
{
//do something with the file
}
}

The only think to notice is that we are looping on the thread1.CancellationPending not being set to true. This allows us to Stop the thread by pressing the stop button.When the Stop button is pressed the
private void thread1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{}
is called. Use this function to do any clean up code and ideally write the log file.Next we will code the Start and Stop Buttons:Code:StartThe code for the start button is pretty simple. Basically we would like to disable the start button enable the stop button and call the thres to start
Code:

private void btnStart_Click(object sender, EventArgs e)
{
btnStart.Enabled = false;
btnStop.Enabled = true;
thread1.RunWorkerAsync();
}