How to call multiple different methods simultaneously - asp.net

Question

I have some different methods that each import products from different sites.
If I execute these sequentially the entire process takes a lot of time, particularly when 1 method is running on a site that is less responsive.
I'd rather run them simultaneously.
This is what I have so far with 1 example method:
Public Class feedParameters
Private _productIdPrefix As String
Private _publishersite As String
Private _feedURL As String
Public Property productIdPrefix() As String
Get
Return _productIdPrefix
End Get
Set(value As String)
_productIdPrefix = value
End Set
End Property
Public Property publishersite() As String
Get
Return _publishersite
End Get
Set(value As String)
_publishersite = value
End Set
End Property
Public Property feedURL() As String
Get
Return _feedURL
End Get
Set(value As String)
_feedURL = value
End Set
End Property
End Class
Dim fpm As New feedParameters
fpm.publishersite = "mypublisher.nl"
fpm.feedURL = "http://www.domain.com/test.xml"
fpm.productIdPrefix = "10"
Protected Sub ImportProductsPublisherA(ByVal productIdPrefix As String, ByVal publishersite As String, ByVal feedURL As String)
End Sub
I tried this:
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsPublisherA()), fpm)
Then I get 3 errors that I have not specified arguments for the 3 parameters: productIdPrefix, publishersite and feedURL
I also tried:
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsPublisherA), fpm)
I get this error:
Method 'Protected Sub ImportProductsPublisherA(productIdPrefix As String, publishersite As String, feedURL As String)' does not have a signature compatible with delegate 'Delegate Sub WaitCallback(state As Object)'.
Any help is greatly appreciated!

Answer 1

using System.Threading.Tasks;
namespace Foo
{
public class Bar
{
public void ImportProductsSiteA() { }
public void ImportProductsSiteB() { }
public void ImportProductsSiteC() { }
public void ImportProductsSiteD() { }
public void Execute()
{
var a = Task.Factory.StartNew(ImportProductsSiteA);
var b = Task.Factory.StartNew(ImportProductsSiteB);
var c = Task.Factory.StartNew(ImportProductsSiteC);
var d = Task.Factory.StartNew(ImportProductsSiteD);
Task.WaitAll(a, b, c, d);
}
}
}

Answer 2

Is this WinForms or asp.net?
If winforms create a background worker for each function and start all of them, they will work independently in a separate thread.
If asp.net you want to look at using System.Threading.ThreadPool - http://msdn.microsoft.com/en-us/library/system.threading.threadpool.aspx
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsSiteA))
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsSiteB))
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsSiteC))
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsSiteD))
If you functions take any parameters you can pass them like this:
System.Threading.ThreadPool.QueueUserWorkItem(New System.Threading.WaitCallback(AddressOf ImportProductsSiteA), parameter-here)