C# Discussion Boards - CodeProject

Nnamdi Onyeyiri16-Jul-02 21:16

16-Jul-02 21:16

I am making a download class, kinda ambitious, considering I know little, but, at the moment, it supports paused/resume downloads, and saving the state of the downloads, so the program ccan be shut down, and the downloads will carry on when iots started up again. anyway, i am trying to add support for multiple downlioad locations, and i want to be able to generate a checksum, or something, for the remote file, and the local file, so that i can verify if the file was downloaded successfully, but i do not know how, any help, or pointers in the right direction?

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: File Verifying

leppie16-Jul-02 22:32

leppie

16-Jul-02 22:32

Nnamdi Onyeyiri wrote:
i want to be able to generate a checksum, or something, for the remote file,

Thats not really possible unless you own the internet Smile | :)

I assume you want somethin similar to eDonkey's file hashing to prevent corrupted downloads. Unless you can control the other side, you cant get a checksum.

I also presume you want somethin similar to GetRight's Segmented downloading. Most programs doing this, creates a blank file to the size (from the returned HTTP header) of the downloaded file, then writes to the file byte by byte.

You can easily run a "scan" thru the file to see what is still needed. Also by changing the header sent u can resume most files if the server supports partial content (see below).

Nnamdi Onyeyiri wrote:
i am trying to add support for multiple downlioad locations

In your your Download class change the "URL" property to URL[]. Or if you dont have somethin like that, you might want to create it to keep track of other variables like speed, pingtime and availability. Also note that you will need to make sure each download location has exactly the "same" file by comparing the sizes. Also , you need to make sure that the remote file's date hasnt changed (incase file size is the same) when resuming the download, although some servers might create the file on the fly to prevent leeching Frown | :(

Hope this all helps Smile | :)

Example of header sent for partial content:

!!!! ----Header Sent----
>>>> GET /Downloads/MagicInstall.msi HTTP/1.1
Host: www.dotnetmagic.com
Range: bytes=23232-
User-Agent: Mozilla/4.0 (compatible; MSIE 5.0; Windows 98)
Accept: */*
If-Range: Fri, 12 Jul 2002 18:28:00 GMT

Example of header recieved for partial content:

!!!! ----Header Recv----
HTTP/1.1 206 Partial Content
Date: Wed, 17 Jul 2002 08:19:38 GMT
Server: Apache
Last-Modified: Fri, 12 Jul 2002 18:28:00 GMT
ETag: "1441e9-8b600-3d2f1fb0"
Accept-Ranges: bytes
Content-Length: 547648
Content-Range: bytes 23232-570879/570880
Content-Type: text/plain

READ MSDN

Re: File Verifying

Nnamdi Onyeyiri17-Jul-02 0:10

Nnamdi Onyeyiri

17-Jul-02 0:10

i was actually gonna do it by doing all the checking and stuff like that.

but for the segmenting, i was gonna allocate each server a section of the file to download, then get them to download to seperate files, then combine the files to one at the end, i was not sure how to get them all to write to the same file at once. Big Grin | :-D

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: File Verifying

leppie17-Jul-02 0:45

leppie

17-Jul-02 0:45

Nnamdi Onyeyiri wrote:
i was not sure how to get them all to write to the same file at once.

Try referencing them all to the same filestream, you will be writing a byte buffer (say 4kb) at any one time, using a lock to prevent (or rather queue) the other threads from writing to the stream at the same time.

READ MSDN

Re: File Verifying

Nnamdi Onyeyiri17-Jul-02 0:53

Nnamdi Onyeyiri

17-Jul-02 0:53

gd idea, BUT, the bytes may not be written in order.

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: File Verifying

leppie17-Jul-02 1:06

leppie

17-Jul-02 1:06

the byte buffer will be written to the file sequencially , you will just need to keep track of the start offset where it should be written in the file for each thread Smile | :)

READ MSDN

Re: File Verifying

Nnamdi Onyeyiri17-Jul-02 2:01

Nnamdi Onyeyiri

17-Jul-02 2:01

ahh i see now.....thanks, ill have a crack at that. if i get it working [ fingers crossed ] ill make an article on it. Smile | :)

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: File Verifying

leppie17-Jul-02 2:32

leppie

17-Jul-02 2:32

If got problems, send me the source as I just created a need to have a class like that as well Smile | :)

Cheers

Good Luck

READ MSDN

Re: File Verifying

Nnamdi Onyeyiri17-Jul-02 2:34

Nnamdi Onyeyiri

17-Jul-02 2:34

leppie wrote:
If got problems, send me the source as I just created a need to have a class like that as well

a download class?

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: File Verifying

leppie17-Jul-02 3:19

leppie

17-Jul-02 3:19

Yes

, something that I want to integtrate into an IRC client i am writing.

READ MSDN

Re: File Verifying

Nnamdi Onyeyiri17-Jul-02 4:02

Nnamdi Onyeyiri

17-Jul-02 4:02

im not writing a program per say, more of im just writing misc classes, and putting them into a dll, for use in future projects.

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Re: File Verifying

leppie17-Jul-02 10:20

leppie

17-Jul-02 10:20

Thats what i meant Smile | :)

Then I wont have to write it Smile | :)

and I can maybe help you better it if neccesary Smile | :)

I am almost 80% complete with my IRC client and HTTP transfer is one of the funtionalities I would like to implement as a plugin to my client, as well as FTP and some file sharing protocols.

Give me a shout then when done please Smile | :)

Cheers

READ MSDN

Re: File Verifying

Nnamdi Onyeyiri17-Jul-02 0:11

Nnamdi Onyeyiri

17-Jul-02 0:11

oh, and one more thing - I planning on owning the internet Poke tongue | ;-P

, one site at a time. Suspicious | :suss:

Suspicious | :suss: Email: theeclypse@hotmail.com URL: http://www.onyeyiri.co.uk
"All programmers are playwrights and all computers are lousy actors."

Windows Service won't start....

Jason.NET16-Jul-02 11:20

Jason.NET

16-Jul-02 11:20

All...

I've written a windows service which works properly on my development machine and on a QA machine. When installing it on a production machine,the service tries to start however after waiting about 30 seconds, it stops and SCM gives an error that the service did not respond in a timely fashion.

I've gone back to my code and commented everything except for a static logging method that I'm using for debugging. The entry point code is listed below...when starting the service, it is failing between logging the 2nd /3rd lines. Keep in mind that all code is commented out in the "transportClass" at this point and it is still failing to start the service. Given that it works beautifully on multiple other machines, I think it must
be configuration of some sort -- any thoughts???

/*******************************
static void Main()

{

LogError("Starting Main");

System.ServiceProcess.ServiceBase[] ServicesToRun;

LogError("Second Line");

ServicesToRun = new System.ServiceProcess.ServiceBase[] { new
transportClass() };

LogError("Third Line");

System.ServiceProcess.ServiceBase.Run(ServicesToRun);

LogError("Exiting Main");

}

*******************************/

Thanks,
Jason Mark
jmark@comcenters.com

Painting a component *after* the form is displayed?

Zombies with Coffee, LLC16-Jul-02 11:21

Zombies with Coffee, LLC

16-Jul-02 11:21

I have added a custom component that draws a big ellipse on a form. (It's much more involved, but keeping it easy for an example)

Inside of the initialization, I add a delegate to the Form's Paint method.

m_Parent.Paint += new PaintEventHandler( this.Paint );

Unfortunately, the delegates are drawn first, and then all of the controls. So, all of the controls are drawn on top of my ellipse and I can't see it.

Since there isn't a method called Painted, how can I get my component to draw on TOP of the other controls instead of on the bottom?!

Re: Painting a component *after* the form is displayed?

Nathan Blomquist17-Jul-02 8:27

Nathan Blomquist

17-Jul-02 8:27

You could try using:

<br />
this.Invalidate();<br />

Call this after everything else has been drawn. The invalidate method causes the control to repaint itself. You may need to remove the handler that you gave in your post. I think this should work, but I can't be sure.

Later,
Nathan

---------------------------
Hmmm... what's a signature?

Windows API Call to change resolution

Brian Olej16-Jul-02 10:35

Brian Olej

16-Jul-02 10:35

Hello everyone,
I have been sifting through code project to find an answer to my question and I came up with with an article about how to make calls to the windows API with C# but it didn't quite answer my problem. How would I make a call to the Window API to change the screen resolution? What would be the call to play sound files (From what I've seen .NET doesnt have any functions to play sound files)?

Re: Windows API Call to change resolution

Eric Gunnerson (msft)17-Jul-02 13:40

Eric Gunnerson (msft)

17-Jul-02 13:40

You would use a call to ChangeDisplaySettings.

This might help:

class Win
{
internal const int ENUM_CURRENT_SETTINGS = -1;

internal const uint DM_BITSPERPEL = 0x00040000;
internal const uint DM_PELSWIDTH = 0x00080000;
internal const uint DM_PELSHEIGHT = 0x00100000;
internal const uint DM_DISPLAYFREQUENCY = 0x00400000;

internal const int CDS_UPDATEREGISTRY = 0x00000001;

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
internal class DEVMODE
{
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
internal string dmDeviceName;
internal ushort dmSpecVersion;
internal ushort dmDriverVersion;
internal ushort dmSize;
internal ushort dmDriverExtra;
internal uint dmFields;
internal short dmOrientation;
internal short dmPaperSize;
internal short dmPaperLength;
internal short dmPaperWidth;
internal short dmScale;
internal short dmCopies;
internal short dmDefaultSource;
internal short dmPrintQuality;
internal short dmColor;
internal short dmDuplex;
internal short dmYResolution;
internal short dmTTOption;
internal short dmCollate;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
internal string dmFormName;
internal ushort dmLogPixels;
internal uint dmBitsPerPel;
internal uint dmPelsWidth;
internal uint dmPelsHeight;
internal uint dmDisplayFlags;
internal uint dmDisplayFrequency;
internal uint dmICMMethod;
internal uint dmICMIntent;
internal uint dmMediaType;
internal uint dmDitherType;
internal uint dmReserved1;
internal uint dmReserved2;
internal uint dmPanningWidth;
internal uint dmPanningHeight;
}

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
internal static extern int EnumDisplaySettings(string lpszDeviceName, int iModeNum, [In, Out] DEVMODE lpDevMode);

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
internal static extern int ChangeDisplaySettings(DEVMODE lpDevMode, int dwFlags);
}

Re: Windows API Call to change resolution

Brian Olej17-Jul-02 14:44

Brian Olej

17-Jul-02 14:44

Thank you

Re: Windows API Call to change resolution

NormDroid20-Jul-02 23:52

NormDroid

20-Jul-02 23:52

Defeats the portability of the application?

Normski. - the next bit of code is self modifying ... jmp 0xCODE

Library File?

mtito16-Jul-02 5:19

mtito

16-Jul-02 5:19

I have 10 different assembilies, I want to put it in One Library file or one assembly, cause I don't want to add references upto 10 times everytime for my different screen. Is anybody know how to do that.

Thanks in advance

Re: Library File?

SHaroz16-Jul-02 8:29

SHaroz

16-Jul-02 8:29

Try putting them all in one project.

XmlTransformation output to string

tomiga16-Jul-02 4:23

tomiga

16-Jul-02 4:23

I have to use xml transformation.
The simplest way is

<br />
XslTransform xsltransform = new XslTransform();<br />
xsltransform.Load("favorite.xsl");<br />
xsltransform.Transform("MyDocument.xml", "TransformResult.xml");<br />

But it is necessery for me to put output of transformation not to file but to string... (all of overloaded members of Transform has file or stream)

Do you have any idea?

Re: XmlTransformation output to string

James T. Johnson16-Jul-02 11:42

James T. Johnson

16-Jul-02 11:42

tomiga wrote:
(all of overloaded members of Transform has file or stream)

You could create a memory stream to house the output of the transformation; then once the transformation is done convert the underlying byte array to a string.

System.Text.(Encoding).GetString(myByteArray) if the XML file uses ASCII then (Encoding) should be ASCIIEncoding; if it uses UTF8 then it should be UTF8Encoding; etc...

James
"Java is free - and worth every penny." - Christian Graus

Re: XmlTransformation output to string

tomiga16-Jul-02 20:37

tomiga

16-Jul-02 20:37

Thx. I have found stream witch writes output to string. StringWriter class. It helps me to solve problem.

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