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Thanks for quick reply
The problem is it works for some time and then the error occurs...
i have displayed a messagebox. the messagebox is displayed 4-5 times and then the error occurs.
The main purpose of the application is i am capturing images from a camera and sending it over network.
So when i receive it back and try to convert it from a byte array to an image the error occurs.
Can u suggest any better way for this?
or what should be done if the byte array doesn't contains all the information?
Thanks & Regards,
Pramod
"Everyone is a genius at least once a year"
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If it's not all there, there's not much you can do. If it works sometimes, then I guess perhaps sometimes the info is lost, assuming it's being created correctly in the first place.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
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You aren't saying how you converted it to a byte array to begin with. If the byte array only contains the bitmap's pixel data, it's not going to work. You have to save the full bitmap data, including the header information. You can do this by using Bitmap.Save(), passing in a MemoryStream that points to the byte array.
If you want to create a bitmap from raw pixel data (without a header), you must give GDI+/System.Drawing the information it needs in order to interpret the pixel data. You can create an empty bitmap of the right size and format, and copy the data into it using Bitmap.LockBits() and Buffer.Copy(), or you can create a bitmap that directly uses the byte array as its pixel storage - see my EditableBitmap class[^] for an example.
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i have used the Save method of the image to save that to a memory stream and then used the ToArray method of the memory stream to convert the image to byte array
actually the image is captured from a cam and displayed in a picturebox,
so i cannot use the above mentioned method, coz that will lock the image, is wht i think.
is there any other way to do that?
Thanks & Regards,
Pramod
"Everyone is a genius at least once a year"
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Hi,
Ok now this is just weird. i used this line of code everyday and worked fine and suddenly this morning just threw an error in my face 
<br />
DateTime dt = Convert.ToDateTime(cpCreateDate.SelectedDate.ToString("dd/MM/yyyy"));<br />
ok the cpCreateDate control is a datetime picker and the value is for example
"09/01/2007 12:00:00 AM"
all i want to do is format it to only the date meaning removing the time to save this to a sql database.
the problem is that as soon as it converts the string back to a datetime value it keeps on adding the time back again and i get this error when trying to write the value to the database:
"The conversion of char data type to smalldatetime data type resulted in an out-of-range smalldatetime value.
The statement has been terminated."
the column in the sql database table is a smalldatetime data type and changing that to normal datetime doesnt resolve this.
please help
thanks
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Wouldn't this be easier ?
DateTime dt = new DateTime(cpCreateDate.SelectedDate.Year, cpCreateDate.SelectedDate.Month, cpCreateDate.SelectedDate.Day) ?
A lot less expensive than string to date conversions.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
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//you can use substring method like this:
cpCreateDate.SelectedDate.ToString("dd/MM/yyyy").Substring(0,10)
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I think you are trying to strip time because you think that small date time is only date field (lots of users think that, i don't know why, i guess there is something like that in Access), but that is not true. This data field just shortens range of valid values while keeping the time. Valid dates for a SMALLDATETIME column can range from January 1, 1900 to June 6, 2079.
If I'm wrong, and that is not what error is about than you can simply strip time with:
cpCreateDate.SelectedDate.Date;
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You can also poke your eyes out with a screwdriver, but it doesnt mean its a good idea.
hint: what happens to your code when my date format is long date ie/09 January 2007
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Hi all,
I'm coding a sql server job monitor usnig sql-dmo and c#.
I need help on how to use JobFilter interface.
Here is a sample of my code:
JobFilter _jf = null;
_jf.Category = "SAGAII";
QueryResults _qr = _srv.JobServer.EnumJobs(_jf);
The code results in an error.
Please help!
Thanks in advance
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Hi all,
I have a problem manipulating form contrls in user thread or our made threads.
In VS 2003 this code was running fine that is on a button click we make a new thread , pass it the function to call and start it but in VS 2005 it is making problem and giving a "CROSS THREAD OPERATION EXCEPTION". I dont knw why. Is there a way to call the threaded function and manipulate MULTIPLE form controls.
Thanks in adv
Reply soon ![Rose | [Rose]](https://codeproject.freetls.fastly.net/script/Forums/Images/rose.gif)
private void button1_Click(object sender, System.EventArgs e)
{
Thread newthrd = new Thread(new ThreadStart(Increment_ProgressBar));
newthrd.Start();
}
private void Increment_ProgressBar()
{
for(int count=0;count<101;count++)
{
progressBar1.Value = count;
Thread.Sleep(100);
}
}
Bye
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UI controls should only be accessed from the thread they were created on cause otherwise your application may show some strange behaviour e.g. freezes. Obviously you were lucky and never encountered such problems, but it doesn't mean they will never occur. To inform developers about this possible problem the CrossThreadOperationException is thrown in Framework 2.0.
Some information and ways to get around are presented in this good CP article: What's up with BeginInvoke?[^]
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning." - Rick Cook www.troschuetz.de
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I dont have one control to deal on... the number is about 50. so do i've to call begininvoke() for every control im using. isnt there a possible way out like in VS2003.
Bye
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Mr.Sam wrote: so do i've to call begininvoke() for every control im using.
As said you should always use Invoke or BeginInvoke when accessing an UI control from a thread other than the one it was created on. In case you access many controls from your worker thread you could maybe encapsulate all manipulations of the UI in one method and invoke it whenever you want to update the user interface.
Mr.Sam wrote: isnt there a possible way out like in VS2003.
Take a look at Christian's answer.
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning." - Rick Cook www.troschuetz.de
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hint: it won't work with the Thread, but if ever you should use the Timer class look into the SynchronizingObject property.
V.
I found a living worth working for, but haven't found work worth living for.
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You can turn that exception off, but it's better to write code that doesn't do this, the error is there for a reason.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
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Ok, looks like no one will give you the "dirty" answer.
Set Control.CheckForIllegalCrossThreadCalls to false when you start up your program and no changes will be necessary. You should be aware this is not proper coding, but for projects that ran ok under VS2003 it's always worked for me. Just be sure to avoid it for anything new you make.
In my opinion Ms could have avoided this issue easily, a mechanism to fix it can be quite easily made, I find doing it over and over again is extremely annoying...
Standards are great! Everybody should have one!
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thanx but where shud i write this line in my code
Bye
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Well, you shouldn't really. If you're gonna use it, put it before your System.Windows.Forms.Application.Run().
Standards are great! Everybody should have one!
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Thanx a lot man you really solved the problem
Bye
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Nope, didn't solve anything, just ignored it... 
Seriously, you should check your program for bugs, there's no guarantee nothing "bad" will happen. Good luck.
Standards are great! Everybody should have one!
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Hi,
if you are lucky you can still do everything on the UI thread by using a
System.Windows.Forms.Timer; your example sure could benefit from it, since
it basically sits sleeping all the time.
if your new thread is there because some real work needs to be done, you could
have that thread set an int progress value, and have a System.Windows.Forms.Timer
with an event handler that updates your progress bar (yes, this is a polling situation,
but hey, it may well be cheaper than the Invoke stuff anayway).
but when your worker thread needs to really interact with one or many controls,
then the InvokeRequired/Invoke/BeginInvoke stuff is necessary.
It then becomes a design decision on how to partition the work; I prefer to use
lightweight methods that do multiple control access at once on the UI thread, so I call
them (with Invoke) when I need them, rather than doing the Invoke stuff for every
individual control access. It goes together with structuring your code anyway...
Luc Pattyn
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Can you plz give me a sample code for manipulating multiple controls using invoke so the real application is responsive and the thread is working on controls.
Thx
Bye
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Hi,
assume a text editor with most operations running on main (= UI) thread, but with search capabilities running on a background thread. When search thread has found what it was
looking for, it calls UpdateSelection() methode to update several things in the user
interface.
Since UpdateSelection is not called from UI thread and needs to access some
controls, we make it such that it calls itself again, this time on UI thread:
public delegate void UpdateSelectionDelegate(int start, int length);
private TextBox textBox;
private MenuItem menuCopy;
private MenuItem menuCut;
public void UpdateSelection(int start, int length) {
if (InvokeRequired) {
Invoke(new UpdateSelectionDelegate(UpdateSelection),
new object[]{start, length});
} else {
textBox.Select(start, length);
menuCopy.Enabled=length!=0;
menuCut.Enabled=length!=0;
}
}
In the example three controls get updated by implementing and executing only one Invoke.
Luc Pattyn
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Cheers for you but can u plz paste the whole code here or refer to the article.
thanks in advance
Bye
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