|
How to calculate CRC of the forllowing message
Byte|Word|Word|Byte|CRC|CRC
SAS ![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
|
|
|
|
|
What kind of CRC? See [^].
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
|
|
|
|
|
I want to calculate CRC for modbus bytes
|
|
|
|
|
See the article (and post specific to modbus) here[^]
|
|
|
|
|
|
Hello,
Is it really not possible anyway to KILL a running background worker Instantly ? I know it is may be possible by using Thread object but now my application is completely developed using background worker and an user really cant stop a running worker thread as he/she has to depend on race condition and Cancellation Pending property.
Thanks again
Emran
|
|
|
|
|
Hi,
you should not kill/abort threads that may hold resources, open files, whatever. (as
almost all useful threads do).
It is much preferred to use one or more flags that get tested regularly by your thread's code.
Luc Pattyn
|
|
|
|
|
Hi Luc Pattyn,
Thanks a lot for your valuable reply.
Actually I thought there must be a way to abort a background worker safely. Because, when I want to stop a Music which is being played by a player, as a user I should not care how the resources are being used, I know by all means that I want to stop the music playing right a way. My application has some similar situation, but my user is forced to wait for the background worker\s dumb loop where the cancellation flag is checked. And if some reason the background process is stucked and never coming back to check the flag, the user can’t ever stop the process.
As you said I should use Flags. Yes, background worker object provides a flag named "cancellation pending" and I am already using that to check if it should be aborted. But is not there any better solution to stop like a Music player?
Regards
Emran
|
|
|
|
|
This is how I would construct a music player:
have one thread that manages all the music-related resources
have a second thread that does actual sound generation; it gets created when necessary, and
may get killed at all (or some) times, by the manager thread, provided the manager thread is
able to clean up everything. SO in more detail: the user tells the program to stop, the
UI thread tells the manager thread, which in turn, when it feels able to clean up, kills
the sound thread and then cleans up after it.
So in this scheme, two threads cooperate, only one gets killed, being the one NOT responsible
for the resources involved. Now you still must be carefull about synchronizing those threads,
one thing you can not use is locks, since the killable thread is not allowed to hold a lock
that would prevent the manager thread to ever become active again !
Hope this helps.
Luc Pattyn
|
|
|
|
|
Thanks Luc Pattyn,
I understood about killing for Thread opbjects. But there is no method available similar to Abort() or Kill() for BackgroundWorker Objects. I have developed my application using Background worker now I am looking for a way to Stop it instantly.
Is there any way to do that ?
Thanks
Emran
|
|
|
|
|
I havent used BackgroundWorker yet; I have been using some Threadpool threads, but most
often I create my own threads, so I have full control over them, can change their
priorities, and can carefully kill them !
It seems like BackgroundWorker does not provide an immediate kill; you could make one
by getting the working code start with a Thread.GetCurrentThread() but I dont like
that idea very much. For one you are not supposed to kill a Threadpool thread (it isnt yours to
begin with), and I expect the same applies to the BackgroundWorker stuff.
Luc Pattyn
|
|
|
|
|
I am using the following code to do a rotation. This rotates the object about the Point(0, 0). My question is how do I translate in order for the object to rotate about its center point??
Matrix m = new Matrix();
...
m.RotateAt(this.ObjectAngle, this.ObjectRectangle.Location);
g.Transform = m;
this.ObjectRegion.Transform(m);
...
Any help would be greatly appreciated!
Thanks
Theres light at the end of the tunnel, hope it ain't no train.
|
|
|
|
|
It takes one statement:
Image.RotateFlip(RotateFlipType.Rotate180FlipNone);
Luc Pattyn
|
|
|
|
|
The other advice you were offered is wrong ( and weird )
You set a translate transform to make the point of rotation the centre of the image ( so, half the width and half the height ). Then you do a rotate transform to rotate it, and set the translate back again, so it draws where you expect it to.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
|
|
|
|
|
Christian Graus wrote: The other advice you were offered is wrong ( and weird )
In may simple image processing app, I have one image (a field "private Bitmap image;"),
a paint event handler that contains
Graphics g=e.Graphics;
int w=image.Width;
int h=image.Height;
Rectangle r=new Rectangle(x, y, w*zoomT/zoomN, h*zoomT/zoomN);
g.DrawImage(image,r);
where x, y are globals indicating top left position, and zoomT,zoomN are zooming parameters.
and some controls that trigger image operations; some of them take the form:
image.RotateFlip(RotateFlipType.Rotate90FlipNone);
The above rotate statement gives me a new image that is a rotated copy of the
original. It works just fine, as simple as that. Nothing weird, and no surprises either.
Luc Pattyn
|
|
|
|
|
Luc Pattyn wrote: The above rotate statement gives me a new image that is a rotated copy of the
original. It works just fine, as simple as that. Nothing weird, and no surprises either.
Yes, if he wanted to rotate the actual bitmap, as opposed to drawing it rotated, and he only wanted to rotate 90, 180 or 270 degrees, this would work just fine. It just wasn't an answer to what the OP was asking about.
Christian Graus - C++ MVP
'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert
|
|
|
|
|
Thank you for your help Christian I am going to check it out. It does make sense to me now that the coffee has kicked in!
Theres light at the end of the tunnel, hope it ain't no train.
|
|
|
|
|
This would probably work fine but am writting a cad type app where I need to rotate in smaller increments than 90, 180, 270!
Thank you for you time though!
Theres light at the end of the tunnel, hope it ain't no train.
|
|
|
|
|
Hi.
Can you make the orientation of a Windows Forms ProgressBar to be vertically?
Thanks.
|
|
|
|
|
|
hi big guns. i got a problem how to compare the contents of two are more files. plz plz help me
tahir shah
|
|
|
|
|
please explain what you want. What kind of files, big/small, what kind of result.
is it bool AreIdentical(), or string[] GetDifferences(), or ... ?
Luc Pattyn
|
|
|
|
|
how do i override the behaviour performed when the column header of a datagrid is clicked to sort the rows according to that column? thanks!
I am a SysAdmin, I battle my own daemons.
|
|
|
|
|
I have tried to make a multi-tab browser using some of the information from this[^] post. I have a button that opens up a new tab with a browser in it. But when i go back to the other tab, the browser is gone from that tab! The code i used is...
tabControlBrowser.TabPages.Add("http://www.google.com");
int tabCount = tabControlBrowser.TabCount;
tabControlBrowser.TabPages[tabCount - 1].Controls.Add(webBrowser);
tabControlBrowser.SelectTab(tabCount - 1);
Your help is appreciated!!!
|
|
|
|
|
dsl/fahk wrote: tabControlBrowser.TabPages[tabCount - 1].Controls.Add(webBrowser);
You're moving your webbrowser control between pages, instead of creating a new one
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
