Threading for methods on button click - asp.net

Question

I am calling few methods on a button click.
functionA()
functionB()
functionC()
All three functions are independent from each other and they take long time to execute. I checked and found that by threading I can run all three together which will save the execution time.
As I am new to threading concept, could anyone please guide me the simplest way I can do threading in scenario or other way which will be useful in this scenario.
EDIT
One more problem in the same function:
I am binding 5 gridviews after the three functions execution. Like this
gv1.DataSource = GetData("Mill");
gv1.DataBind();
gv2.DataSource = GetData("Factory");
gv2.DataBind();
gv3.DataSource = GetData("Garage");
gv3.DataBind();
gv4.DataSource = GetData("Master");
gv4.DataBind();
They all are using the same method for getting the result and they are also taking time to load. Is there any way I can run them parallel too? I afraid, because they are using same method to get the data. Is it possible to do threading for them. How ?

Answer 1

I am not sure how Parallel.Invoke() decides what to execute in parallel, but if you want an assurance that they will execute in parallel, use threads:
var t1 = new Thread(MySlowFunction);
t1.IsBackground = true;
t1.Start();
var t2 = new Thread(MySlowFunction);
t2.IsBackground = true;
t2.Start();
# To resync after completion:
t1.Join();
t2.Join();
Or even better, use the ThreadPool:
ThreadPool.QueueUserWorkItem(MyWork);
Remember to handle your thread exceptions.

Answer 2

The simplest answer is to use MSDN: Parallel.Invoke().
You should also consider: Asynchronous Pages.

Answer 3

Try using System.Threading.Tasks namespace
Something like
var task1 = Task.Factory.StartNew(() => DoA());
var task2 = Task.Factory.StartNew(() => DoB());
var task3 = Task.Factory.StartNew(() => DoC());
Task.WaitAll(task1, task2, task3);
http://www.codethinked.com/net-40-and-systemthreadingtasks

Answer 4

Here's an example which will execute the 4 tasks in parallel:
public partial class _Default : System.Web.UI.Page
{
public class MyViewModel
{
public int Id { get; set; }
public string Name { get; set; }
}
protected void Page_Load(object sender, EventArgs e)
{
}
protected void BtnBindClick(object sender, EventArgs e)
{
// we define the input for the tasks: each element consists
// of the grid we are willing to bind the results at the end and
// some optional parameter we want to pass to the GetData function
var inputs = new[]
{
new { Grid = gv1, Input = "Mill" },
new { Grid = gv2, Input = "Factory" },
new { Grid = gv3, Input = "Garage" },
new { Grid = gv4, Input = "Master" },
};
// define the tasks we want to execute in parallel
var tasks = inputs
.Select(x => Task.Factory.StartNew(
() => new { Grid = x.Grid, Output = GetData(x.Input) })
)
.ToArray();
// define a task which will be executed once all tasks have finished
var finalTask = Task.Factory.ContinueWhenAll(tasks, x => x);
// wait for the final task
finalTask.Wait();
// consume the results
foreach (var item in finalTask.Result)
{
if (item.Exception == null)
{
// if no exception was thrown for this task we could bind the results
item.Result.Grid.DataSource = item.Result.Output;
item.Result.Grid.DataBind();
}
}
}
private MyViewModel[] GetData(string input)
{
// Simulate slowness
Thread.Sleep(1000);
return Enumerable.Range(1, 5).Select(x => new MyViewModel
{
Id = x,
Name = input
}).ToArray();
}
}