Re: Working with very large numbers. - C# Discussion Boards

Henry Minute8-Sep-09 10:57

8-Sep-09 10:57

If you Google for c# play avi or c# play mp4 you will get loads and loads of hits. Some have code, some only descriptions of how to do it.

Have a go yourself.

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Overwrite an image

vandel2128-Sep-09 5:55

vandel212

8-Sep-09 5:55

Hi, I'm currently using Visual c# 2008 express edition. I'm trying to save an image over a file with the same file name. When it attempts to do this is bombs out because it says either it's a generic GDI+ error or the process is already in use. This makes perfect sense why it would throw those errors, but how can I overwrite the file so that it doesn't give me this problem. I've tried Opening a file stream around it then closeing it. useing the bmpPicture.Dispose(), and GC.Collect(), none of those work.Is there something else I could try? or perhaps something I'm doing wrong?

here is a snippet of my code:

<br />
private void SaveFile()<br />
        {<br />
                // Set the bitmap object to the size of the screen<br />
                bmpPicture = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);<br />
                // Create a graphics object from the bitmap<br />
                gfxScreenShot = Graphics.FromImage(bmpPicture);<br />
                // Take the screenshot from the upper left corner to the right bottom corner<br />
                gfxScreenShot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y + 25, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);<br />
                // Save the screenshot to the specified path that the user has chosen                 <br />
                bmpPicture.Save(FilePath, ImageFormat.Bmp); //****THIS IS WHERE THE ERROR IS THROWN****<br />
        }<br />

Re: Overwrite an image [modified]

Luc Pattyn8-Sep-09 6:08

Luc Pattyn

8-Sep-09 6:08

Hi,

a likely cause for bmpPicture.Save(FilePath, ImageFormat.Bmp); to throw an exception is the file is locked "by another process", which typically means your own process (or maybe some other) has the file open. Typically you would have loaded it either with Image.FromFile() or PictureBox.Load()

Images loaded that way keep their file open for as long as they exist. There are three remedies:

1. quick and dirty
get the picture, make sure you don't need it anymore, call dispose:

Image img=PictureBox.Image;
PictureBox.Image=null;
img.Dispose();
img=null;
// now the original file is unlocked unless you are still using the image somewhere else...

2. quick and dirty
when you initially get the image, make a copy and throw away the original:

Bitmap bm2=null;
{
    Bitmap bm1=Image.FromFile("image.jpeg");
    bm2=new Bitmap(bm1);
    bm1.Dispose();
}
// now use bm2, the file is unlocked (bm1 is out of scope already!)

3. clean and easy
don't use Image.FromFile nor PictureBox.Load; instead use Image.FromStream

Bitmap bm=Image.FromStream(File.OpenRead("image.jpeg"));

[EDIT] Bug fixed in my other reply ]/EDIT]

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

modified on Tuesday, September 8, 2009 1:53 PM

Re: Overwrite an image

harold aptroot8-Sep-09 6:10

harold aptroot

8-Sep-09 6:10

vandel212 wrote:
GC.Collect()

Is that really necessary? It usually isn't..

Re: Overwrite an image

Luc Pattyn8-Sep-09 7:58

Luc Pattyn

8-Sep-09 7:58

Sorry, the third option ("clean and easy") wasn't entirely correct, as the stream does not get closed/disposed of. Here is a better way:

Bitmap bm=null;
using (FileStream stream=File.OpenRead("image.jpeg")) {
    bm=Image.FromStream(stream);
}

So in the end, there isn't a single-line solution.

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Taking a snapshot from a local webcam...

to_aru_shiroi_neko8-Sep-09 5:37

to_aru_shiroi_neko

8-Sep-09 5:37

My goal is to preform various image processing tasks on an image taken by a webcam...

After googling, and trying different examples... I failed to find a simple solution. Example code is either overly complicated or it only supports WIA webcams only.

I like how "Motion Detection Algorithms[^]" works (for stills) however the code is overly complicated for the task I want to preform with a mind blowing 48 .cs files...

I tried trimming down but ended up with 26 files of code I have no clue on...

All I want to do is take a still or two every five minutes... Any suggestions on this simple sounding yet strangely complicated task?

Working with very large numbers.

JTKRIST8-Sep-09 5:13

JTKRIST

8-Sep-09 5:13

My problem is simply that I am trying to make a simple command line RSA encryption program and was trying out the number 123^17 and don't seem to be able to store the value anywhere because of its size. How can I work with numbers that are bigger than 10^20?

Re: Working with very large numbers.

Luc Pattyn8-Sep-09 5:22

Luc Pattyn

8-Sep-09 5:22

integers or reals?

search CodeProject (or google) for either BigInt or BigNumber, and you will find several classes that take care of it, not all at the same quality level though.
This[^] one you may like, no guarantees.

C# 4.0 has a BigInt class built-in, I haven't had a look yet.

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Re: Working with very large numbers.

Richard MacCutchan8-Sep-09 5:26

Richard MacCutchan

8-Sep-09 5:26

Try the System.Decimal type which can hold values from ±1.0 × 10^−28 to ±7.9 × 10^28 with precision of up to 28-29 significant digits.

Re: Working with very large numbers.

harold aptroot8-Sep-09 5:39

harold aptroot

8-Sep-09 5:39

I've found that fixed-length number structs are usually better for relatively short numbers. Looks like 128bit should do in your case - and that's easy to make (just put 2 ulongs together in a struct, all operations except division and modulo are easy to extend)

Re: Working with very large numbers.

DaveyM698-Sep-09 5:40

DaveyM69

8-Sep-09 5:40

I did try this ages ago but can't remember much about it. J# has a big integer class - see here[^], you can use this from C#.

There is also IntX[^] which I've never used but seen recommended.

Dave

Generic BackgroundWorker - My latest article!
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

How to notify all instance of a class that a change is happened

Nitheesh George8-Sep-09 4:48

Nitheesh George

8-Sep-09 4:48

Hi,

I am using VS 2008 to develop an application. In this application
i have List<> of Contacts. This list may contain thousands of contact's.
I have
class Contact
{
......
.........
};

i want to give a signal to all instances of this class that a changed had happen. How can i do this.

thanks

Nitheesh

Jose Jo Martin

http://www.simpletools.co.in

Re: How to notify all instance of a class that a change is happened

monstale8-Sep-09 5:16

monstale

8-Sep-09 5:16

Hi,

you could create your own event:

http://msdn.microsoft.com/en-us/library/aa645739(VS.71).aspx[^]

bye

compile

sanforjackass8-Sep-09 4:27

sanforjackass

8-Sep-09 4:27

how can i compile file from DOS and make if an exe file?

Re: compile

stancrm8-Sep-09 4:30

stancrm

8-Sep-09 4:30

You can find the compiler in :

C:\WINNT\Microsoft.NET\Framework\v2.0.50727\csc.exe

This is just for example. Probably is your windows in C:\Windows

Then the command is :
http://msdn.microsoft.com/en-us/library/78f4aasd.aspx[^]

Re: compile

Manas Bhardwaj8-Sep-09 4:39

Manas Bhardwaj

8-Sep-09 4:39

You may want to have a look at these

Working with the C# 2.0 Command Line Compiler[^]

Building from the Command Line[^]

Manas Bhardwaj
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

is there any way to create a new Process from a Stream? [modified]

Demasoni8-Sep-09 3:51

Demasoni

8-Sep-09 3:51

alternative for this:

MemoryStream ms = new MemoryStream();
ms.Write("one exe file");
Process.Start(ms);

)
i have an encoded exe, i want to decode it on memorystream and then run it, so nobody can see original exe file! so i can not use a temp file on HDD!
other way?

modified on Tuesday, September 8, 2009 10:06 AM

Re: is there any way to create a new Process from a Stream?

harold aptroot8-Sep-09 3:55

harold aptroot

8-Sep-09 3:55

Write it to a temporary file?

Re: is there any way to create a new Process from a Stream?

OriginalGriff8-Sep-09 3:56

OriginalGriff

8-Sep-09 3:56

This may sound like a stupid question, but why would you want to do that? If you have the process name, path and parameters why put it to a stream fisrt? If the stream contains more than the name, path and parameters, then what do you expect to happen with the excess data?

No trees were harmed in the sending of this message; however, a significant number of electrons were slightly inconvenienced.

This message is made of fully recyclable Zeros and Ones

Re: is there any way to create a new Process from a Stream?

Dave Kreskowiak8-Sep-09 4:39

Dave Kreskowiak

8-Sep-09 4:39

There is no other way. You have to write it to a temporary file. Besides, if your app requires that kind of security, you're still not going to stop the right person from grabbing it straight out of memory.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: is there any way to create a new Process from a Stream? [modified]

Luc Pattyn8-Sep-09 5:24

Luc Pattyn

8-Sep-09 5:24

you might create a (temporary) memory-resident file system, create a file in there, and execute it. Google + some stamina required.

klik[^]

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

modified on Tuesday, September 8, 2009 1:04 PM

Re: is there any way to create a new Process from a Stream?

Dave Kreskowiak8-Sep-09 6:54

Dave Kreskowiak

8-Sep-09 6:54

Luc Pattyn wrote:
you might create a (temporary) memory-resident file system, create a file in there, and execute it. Google + some stamina required.

I was going to suggest writing his own Loader in place of Windows version, but I thought it would have been a bit too overboard. Wink | ;)

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: is there any way to create a new Process from a Stream?

Luc Pattyn8-Sep-09 6:59

Luc Pattyn

8-Sep-09 6:59

Dave Kreskowiak wrote:
a bit too overboard.

Nah. If and when we go too overboard, we get a "plz send me the code" reply to straighten us out. Laugh | :laugh:

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Error when trying to make a web service client

SorenBerggreen8-Sep-09 3:23

SorenBerggreen

8-Sep-09 3:23

Hi all

I've made a web service client, that I'm going to use to call a public web service.

But I keep getting this error:

Could not find endpoint element with name 'basicHttpEndpoint' and contract 'oes.dk.NavisionStatIntegrationService.INavisionStatIntegrationService' in the ServiceModel client configuration section. This might be because no configuration file was found for your application, or because no endpoint element matching this name could be found in the client element.

I'm rather new at this web service thing, so I'm not sure what to do here.
I've been browsing the net for answers but nothing good has come up.

This is the client part of the app.config:

<client><br />
      <endpoint address="https://test3.oes.dk/NavisionStatIntegrationServiceTest/NavisionStatIntegrationService.svc"<br />
          binding="basicHttpBinding" bindingConfiguration="basicHttpEndpointBinding"<br />
          contract="oes.dk.NavisionStatIntegrationService.INavisionStatIntegrationService"<br />
          name="basicHttpEndpoint" /><br />
</client>

The code I call:

proxy = new NavisionStatIntegrationServiceClient("basicHttpEndpoint");<br />
proxy.ClientCredentials.UserName.UserName = this.UserName;<br />
proxy.ClientCredentials.UserName.Password = this.Password;<br />
this.NSResponse = proxy.InvokeNavisionStatIntegration(this.companyIdentifier, this.immediateExecuting, this.NSRequest);<br />
return this.NSResponse;

This is the code for the NavisionStatIntegrationServiceClient:

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]<br />
[System.ServiceModel.ServiceContractAttribute(Namespace = "http://www.oes.dk/NavisionStatIntegrationService/2009/05/25", ConfigurationName = "oes.dk.NavisionStatIntegrationService.INavisionStatIntegrationService")]<br />
    public interface INavisionStatIntegrationService<br />
    {<br />
        [System.ServiceModel.OperationContractAttribute(Action = "http://www.oes.dk/NavisionStatIntegrationService/2009/05/25/INavisionStatIntegrat" +<br />
            "ionService/InvokeNavisionStatIntegration", ReplyAction = "http://www.oes.dk/NavisionStatIntegrationService/2009/05/25/INavisionStatIntegrat" +<br />
            "ionService/InvokeNavisionStatIntegrationResponse")]<br />
        string InvokeNavisionStatIntegration(string companyIdentifier, string immediateExecuting, string NSRequest);<br />
    }

Re: Error when trying to make a web service client

Keith Barrow8-Sep-09 3:53

Keith Barrow

8-Sep-09 3:53

You'll get a much better response if you post this in the WPF/ WCF / WF forum instead.

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