Programming Threads under Compact Framework

Probably every person who programs under the .NET Framework or Compact Framework, at least once in his life faced with threads (Thread). And often there was a problem of starting a function with a call to a static method, in particular this concerns those methods where a change in the form controls occurs. In this article I will tell you how to solve this problem.

Consider the following example. There is some function foo ():

int a=0;
void Foo()
{
for ( int i=0;i<100000;i++)
{
a++;
}
MessageBox.Show(a.ToString());
}

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The easiest way to perform this function in a stream:

using System.Threading;
…
Thread thr= new Thread(Foo);
thr.Start();
…

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Now we change our function like this:

int a=0;
void Foo()
{
for ( int i=0;i<100000;i++)
{
a++;
label1.Text=a.ToString();
}
}

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As a result, an error will occur:

SmartDeviceProject1.exe
NotSupportedException
Control.Invoke must be used for a separate thread.
...
at System.Windows.Forms.Control.get_Text ()
at System.Windows.Forms.Control.set_Text (String value)
at SmartDeviceProject.Form1.Foo ()

This means that the interaction with the control should be in a separate thread.
Another way is to use the thread pool and the delegate:

ThreadPool.QueueUserWorkItem( delegate { Foo(); });

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Under Windows, everything is fine, but under Windows Mobile the same error pops up.
To solve this problem, you need to use the Invoke method for each control.
Create a Label1 text change function:

void ChangeLabel1Text( string text)
{
label1.Text = text;
}

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Add a delegate for this function:

delegate void ChangeLabel1TextDelegate( string text);
ChangeLabel1TextDelegate cltd;
cltd = new ChangeLabel1TextDelegate (ChangeLabel1Text);

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In the function Foo () we change the string

label1. Text = a.ToString ();

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on:

label1.Invoke(cltd, a.ToString());

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We start the flow for execution:

ThreadPool .QueueUserWorkItem( delegate { Foo(); });

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Everything. Now when you start the program on a PDA or smartphone, you will see numbers from 1 to 100,000.

Original: forum.wce.by/viewtopic.php?f=15&t=14221&start=0