Peter Ritchie's MVP Blog - All Comments

re: Thread.Sleep is a sign of a poorly designed program.

mnjrupp — Tue, 29 Dec 2009 05:07:02 GMT

I use Thread.Sleep with the .Net ThreadPool in a c++ CLI winform app. I don't have the luxury of the console so a textbox created from the main UI to simulate console I/O on separate threads is the only alternative I can see.

The threadpool does a great job of keeping tabs on the threads created. Of course I have to Invoke a delegate to communicate with the textbox as well. There is the nasty Exception of cross threading if I don't use seperate threads and a delegate.

Anyone have a better idea. I'm all ears.

Thanks

re: Using Toolbox for Code Snippets in Visual Studio 2005

Joe — Fri, 18 Dec 2009 22:11:06 GMT

This doesn't seem to work for .sql files. Any suggestions?

re: Windows Live Messenger Virus Scanner Settings

ICEMAN — Fri, 18 Dec 2009 19:07:24 GMT

dude you are the man

re: DataContractSerializer.ReadObject is easily confused.

Ostati — Wed, 16 Dec 2009 17:27:13 GMT

This is what I'm using and it works!

public static string SerializeDataContract<TModel>(TModel dataContract)

{

var serializer = new DataContractSerializer(typeof(TModel));

using (var stream = new MemoryStream())

{

serializer.WriteObject(stream, dataContract);

stream.Position = 0L;

return Encoding.UTF8.GetString(stream.ToArray());

}

re: DataContractSerializer.ReadObject is easily confused.

Jesse Houwing — Mon, 14 Dec 2009 12:35:02 GMT

Setting the position to 0 in the memorystream after writing the data and then using a StreamReader to read the data from the memorystream works great as well. I find it more readable... (and it defaults to unicode)

re: Using Toolbox for Code Snippets in Visual Studio 2005

Chi — Wed, 09 Dec 2009 22:10:03 GMT

"...every time I copy code snippets it automatically adds it into the toolbox..."

I have the same problem... anyone knows how to turn it off please?

re: Sudden "...you must have Terminal Server User Access permissions on this computer." Error.

Hans — Mon, 07 Dec 2009 17:04:29 GMT

Thanks! That was I need! :-)

re: Sudden "...you must have Terminal Server User Access permissions on this computer." Error.

gIRISH — Mon, 07 Dec 2009 12:55:37 GMT

gRATE DUDE IT REALLY WORKS THANKS A LOT.........

re: Windows Live Messenger Virus Scanner Settings

Mister — Tue, 01 Dec 2009 08:24:25 GMT

"C:\Program Files\Symantec AntiVirus\Rtvscan.exe" /selfcheck+ /list+ /scroll+ /quit+ /pattern+ /heur+ /scanfile+ /scanboot- /scanmbr- /scanmem- /arch+ /sfx+ /pack+ /mailbox- /adware /unsafe /ah /prompt /all

re: Fundamentals of Object-Oriented Design (OOD) Part 1

Raj — Thu, 26 Nov 2009 13:47:48 GMT

great buddy nice helpfull article need more on Design patterns

re: Thread.Sleep is a sign of a poorly designed program.

Fred — Mon, 23 Nov 2009 16:22:30 GMT

Thanks for the tip, I didn't know that.

In fact, the MSDN doc about the Sleep method is pretty unfair :

"The number of milliseconds for which the thread is blocked."

So from now I will use the System.Threading.Timer class instead...

re: Sudden "...you must have Terminal Server User Access permissions on this computer." Error.

Davide — Fri, 20 Nov 2009 13:08:04 GMT

Thx a lot: this is the only way I found to solve my problem!

re: Thread.Sleep is a sign of a poorly designed program.

PeterRitchie — Sat, 14 Nov 2009 13:56:21 GMT

@Richard. Right, using Thread.Sleep(1) will allow any other thread to take control of the CPU for at least a time-slice.

The question is a little misguided. The parameter to Sleep is the number of milliseconds to sleep. The fact that we're using 1 millisecond as a parameter means it's *really* difficult for any number of threads to be calling Thread.Sleep at the very same time. Then, there's the fact that only one thread at a time per processor is actually running...

Your question suggests to me that you want to dip into thread prioritization. You want to periodically do no work so other applications can do some. But, you don't know what those other applications do or whether stopping your work will benefit them at all. I wouldn't suggest writing your application to do this; there's no way to do it correctly without being the operating system. Using Thread.Sleep(1) in your threads is enough for the operating system to allow other threads to be responsive. It works remarkably well.

Are you using Thread.Sleep(1) and seeing that other applications are being starved of CPU?

re: Thread.Sleep is a sign of a poorly designed program.

Richard — Sat, 14 Nov 2009 08:51:32 GMT

We are looking for a way to relinquish CPU cycles to other applications in a milti-threaded application. If we use sleep.thread(1) in each thread then my assumption is that our other threads will take the CPU.

The question is...how can we use thread.sleep(1) on all of our threads simultaneously so that CPU cycles are open for other applications?

re: Upcoming C# 3 Guidance From Microsoft

PeterRitchie — Wed, 04 Nov 2009 15:38:46 GMT

@Lijo: I don't know of any books that specifically associating language features to SOLID principles. There's a couple of books that have information about SOLID principles (among other things) and C#. Some of the principles would inherently require specific language features (like DI and Generics):

Robert/Micha Martin's Agile Practices and Patterns in C#: www.amazon.ca/.../0131857258

Karl Seguin's free Foundations of Programming eBook: http://bit.ly/2BWCfd

re: Upcoming C# 3 Guidance From Microsoft

Lijo — Wed, 04 Nov 2009 13:47:37 GMT

Hi,

Could you please let me know whether there is any C# 3 book available that explains about how to implement SOLID principles (Open Closed Principle,DI,Likosov, etc) using language features like GENERICS, LINQ, Lambda Expression,etc.

--Sorry if it is a wrong place to ask this question as this is a deviation from the topic.

Thanks

Lijo Cheeran Joseph

re: "Object is currently in use elsewhere" error.

PeterRitchie — Tue, 20 Oct 2009 21:16:44 GMT

@AlanB: GDI+ (the underlying Windows library that Graphics uses) is not thread safe. Adding a Sleep() call like that, as you've noticed, simply slows down your code and reduces the likelihood of having another exception because it simply re-tries that code that failed and it's less likely that another conflicting GDI+ call is being made at the very same time on another thread.

This isn't a solution. Since GDI+ isn't thread-safe you need to synchronize calls to GDI+ on multiple threads. This simply means having a shared lock object and using the C# lock keyword where ever you perform GDI+ operations (i.e. around acquisition of a resource and disposal of the resource).

Since you code isn't the only code that can perform GDI+ operations you can't synchronize all GDI+ code like this. This leaves you to marshal the code back to the GUI thread--which is a drastic design change from what you've got now.

Long story short: you can't perform GDI+ operations reliably on any thread other than the main (GUI) thread.

"Object is currently in use elsewhere" a workaround

Alan8 — Tue, 20 Oct 2009 19:29:19 GMT

I've been getting this error since I moved some graphics code to a background thread.

Every Graphics.FromImage () had a matching Dispose () call, so that wasn't the problem.

It was happening in the Graphics.DrawImage () method. But only the first time.

So I put a try/catch block around the DrawImage () call, and a Thread.Sleep (5) in the catch block before trying the DrawImage () a second time. This worked. Sleep parameters <= 3 ms didn't work.

There's a noticeable pause when this happens, which suggests it's a Microsoft/.NET threading problem. Maybe it will go away in a later version of .NET.

re: Sudden "...you must have Terminal Server User Access permissions on this computer." Error.

Xaj007 — Mon, 19 Oct 2009 13:53:25 GMT

Big big Thanks!

re: Using Toolbox for Code Snippets in Visual Studio 2005

Serdar Osman Onur — Tue, 13 Oct 2009 00:15:28 GMT

nice feature, i was looking for this...