Threading in VB.Net Tips

S.Vinothkumar · #1 (**permalink**) 10-30-2007, 01:00 AM

Hi all,

Here is some tips and answers about threading concept in VB.Net.

Check it out...

S.Vinothkumar · #2 (**permalink**) 10-30-2007, 01:02 AM

What is Multi-tasking ?

It’s a feature of modern operating systems with which we can run multiple programs at same time example Word, Excel etc.

S.Vinothkumar · #3 (**permalink**) 10-30-2007, 01:04 AM

What is Multi-threading ?

Multi-threading forms subset of Multi-tasking. Instead of having to switch between programs this feature switches between different parts of the same program.

Example, you are writing in word and at the same time word is doing a spell check in background.

S.Vinothkumar · #4 (**permalink**) 10-30-2007, 01:08 AM

What is a Thread ?

A thread is the basic unit to which the operating system allocates processor time.

S.Vinothkumar · #5 (**permalink**) 10-30-2007, 01:11 AM

Did VB6 support multi-threading ?

While VB6 supports multiple single-threaded apartments, it does not support a freethreading model, which allows multiple threads to run against the same set of data.

S.Vinothkumar · #6 (**permalink**) 10-30-2007, 01:14 AM

Can we have multiple threads in one App domain ?

One or more threads run in an AppDomain. An AppDomain is a runtime representation of a logical process within a physical process. Each AppDomain is started with a single thread, but can create additional threads from any of its threads.

S.Vinothkumar · #7 (**permalink**) 10-30-2007, 07:23 AM

Which namespace has threading ?
Systems.Threading has all the classes related to implement threading. Any .NET application who wants to implement threading has to import this namespace.

S.Vinothkumar · #8 (**permalink**) 10-30-2007, 07:25 AM

How can we change priority and what the levels of priority are provided by .NET ?

Thread Priority can be changed by using Threadname.Priority = ThreadPriority.Highest.
In the sample provided look out for code where the second thread is ran with a high priority.

Following are different levels of Priority provided by .NET :-

√ ThreadPriority.Highest

√ ThreadPriority.AboveNormal

√ ThreadPriority.Normal

√ ThreadPriority.BelowNormal

√ ThreadPriority.Lowest

S.Vinothkumar · #9 (**permalink**) 10-30-2007, 07:25 AM

What does AddressOf operator do in background ?

The AddressOf operator creates a delegate object to the BackgroundProcess method. A delegate within VB.NET is a type-safe, object-oriented function pointer. After the thread has been instantiated, you begin the execution of the code by calling the Start() method of the thread

S.Vinothkumar · #10 (**permalink**) 10-30-2007, 07:30 AM

How can you reference current thread of the method ?

"Thread.CurrentThread" refers to the current thread running in the
method.

"CurrentThread" is a public static property.

S.Vinothkumar · #11 (**permalink**) 10-30-2007, 07:30 AM

What's Thread.Sleep() in threading ?

Thread's execution can be paused by calling the Thread.Sleep method. This method takes an integer value that determines how long the thread should sleep.

Example,

Code:

Thread.CurrentThread.Sleep(2000)

S.Vinothkumar · #12 (**permalink**) 10-30-2007, 07:31 AM

How can we make a thread sleep for infinite period ?

You can also place a thread into the sleep state for an indeterminate amount of time by calling Thread.Sleep (System.Threading.Timeout.Infinite). To interrupt this sleep you can call the Thread.Interrupt method.

S.Vinothkumar · #13 (**permalink**) 10-30-2007, 07:32 AM

What is Suspend and Resume in Threading ?

It is Similar to Sleep and Interrupt. Suspend allows you to block a thread until another thread calls Thread.Resume. The difference between Sleep and Suspend is that the latter does not immediately place a thread in the wait state. The thread does not suspend until the .NET runtime determines that it is in a safe place to suspend it. Sleep will immediately place a thread in a wait state.

mobilegeek · #14 (**permalink**) 10-30-2007, 07:33 AM

.NET program always has at least two threads running one is the main program
and second is the garbage collector.

S.Vinothkumar · #15 (**permalink**) 10-30-2007, 07:52 AM

What the way to stop a long running thread ?

Thread.Abort() stops the thread execution at that moment itself.

S.Vinothkumar · #16 (**permalink**) 10-30-2007, 07:53 AM

What is Thread.Join() in threading ?

There are two versions of Thread.Join :-

√ Thread.join().

√ Thread.join(Integer) this returns a Boolean value.

S.Vinothkumar · #17 (**permalink**) 10-30-2007, 07:55 AM

The Thread.Join method is useful for determining if a thread has completed before starting another task. The Join method waits a specified amount of time for a thread to end. If the thread ends before the time-out, Join returns true; otherwise it returns False. Once you call Join, the calling procedure stops and waits for the thread to signal that it is done.

Example you have "Thread1" and "Thread2" and while executing 'Thread1" you call "Thread2.Join()".So "Thread1" will wait until "Thread2" has completed its execution and the again invoke "Thread1".

Thread.Join(Integer) ensures that threads do not wait for a long time. If it exceeds a specific time which is provided in integer the waiting thread will start

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
ASP.net threading issue when populating a listbox	$enthil	ASP and ASP.NET Programming	6	11-04-2007 11:24 PM
How to implement threading in VB.Net?	amansundar	VB.NET Programming	2	10-30-2007 07:41 AM
Threading in C# .Net 2005 :	a.deeban	C# Programming	53	09-10-2007 07:27 AM
When working with shared data in threading how do you implement synchronization in a	oxygen	ASP and ASP.NET Programming	1	07-26-2007 04:07 AM
what is the threading model used for ASP.Net?	mobilegeek	ASP and ASP.NET Programming	1	07-21-2007 01:48 AM