Help needed.....Writing a Swap function using pointer variables... - C# Discussion Boards

AFAIK you can only use the Find* method on PKs. You can however try using the DataView and using a RowFilter

I'm creating a custom program that's going to be used to run a "presentation station". The presentation station should enable the user to supply photos from any camera.

I need to replace the windows camera wizard with my own wizard. I'm going to provide some of the functionality of the original one, and a more elegant UI.

How would I approach this? Would Windows Image Acquistion Automation Layer do the job?

A few details. I need to be able to do the following...
- Most importantly - automatically start my wizard when camera is detected. (i would like the scanner to be ignored if possible)
- Transfer images to computer
- Delete image on camera
- Get thumbnails is optional - can be accomplished by getting full images and creating thumbnails manually

hi everybody,

i have some provlems ti find a good way to make difference between 2 datetime.

for example i want the difference between the DateTime.Now and 2004-05-03 12:56:32.
And i would like to have the result like 0year 4m ?h ?m ?s .

DO you have any idea plz.

thx in advance !

DateTime a;
DateTime b;

TimeSpan ts = a - b;

Smile | :)

well i have already test this , but the results are strange :/

DateTime dt = new DateTime(2004,05,17,04,45,20);<br />
			DateTime dt2 = DateTime.Now;<br />
			TimeSpan ts = dt2-dt;<br />
			DateTime result2 = new DateTime(ts.Ticks);<br />
			Console.WriteLine(dt2.ToString());<br />
			Console.WriteLine(dt.ToString());<br />
			Console.WriteLine(result2.ToString());<br />
			Console.WriteLine(result2.ToString("y'y' M'M' dd'd' H'h' mm'm' ss's'"));

Here are the results :

26/09/2004 00:46:50
17/05/2004 04:45:20

12/05/0001 20:01:30
1y 5M 12d 20h 01m 30s

isn't it strange ?

Apusnaias Wrote:
Here are the results :

26/09/2004 00:46:50
17/05/2004 04:45:20

12/05/0001 20:01:30
1y 5M 12d 20h 01m 30s

isn't it strange ?

I think you mean especially strange that you get 1 year. This happens from the Creation of the DateTime object result2. As the MinValue of DateTime is 0001/01/01 00:00:00, you get this date plus the difference between the to dates.

With the TimeSpan object ts you get the difference in seconds, minutes, hour and days; but not for months and years, as this is depending on the Month and year (a Month can have between 28 and 31 days).

For more Info I recommend the MSDN Documentation about TimeSpan and DateTime.

Greets
Roland

Wenn Du diesen Satz irgendwo liest, ignoriere ihn.

hi everybody,
im working on animation project, i need to know how to save a sequence of gif images in a single file in order to create an animated gif, i searched the msdn files but couldnt find anything useful. can anybody help me out??

huda

Hi all,

I am writing a function in C#, which is a method in a class to swap two integers which are the data members of the class. I think pointers must be used only in an unsafe context.
can anyone tell me how to define unsafe context in my problem...here is the function.

using System;
using System.Drawing;
using System.Drawing.Imaging;

namespace SpineAnalyzer
{
public class ConvMatrix
{ --- members initialisation----

public void Swap(int *x, int *y)
{
int temp;
temp=*x;
*x=*y;
*y=temp;
}

public void Flip_Hor()
{
Swap(&TopLeft11,&BottomLeft31);
Swap(&TopLeft12,&BottomLeft32);
Swap(&TopLeft13,&BottomLeft33);
Swap(&TopLeft21,&BottomLeft21);
Swap(&TopLeft22,&BottomLeft22);
Swap(&TopLeft23,&BottomLeft23);
Swap(&TopLeft31,&BottomLeft11);
Swap(&TopLeft32,&BottomLeft12);
Swap(&TopLeft33,&BottomLeft13);
Swap(&TopMid1,&BottomMid3);
Swap(&TopMid2,&BottomMid2);
Swap(&TopMid3,&BottomMid1);
Swap(&TopRight11,&BottomRight31);
Swap(&TopRight12,&BottomRight32);
Swap(&TopRight13,&BottomRight33);
Swap(&TopRight21,&BottomRight21);
Swap(&TopRight22,&BottomRight22);
Swap(&TopRight23,&BottomRight23);
Swap(&TopRight31,&BottomRight11);
Swap(&TopRight32,&BottomRight12);
Swap(&TopRight33,&BottomRight13);
}

public void Flip_Ver()
{
Swap(&TopLeft11,&TopRight13);
Swap(&TopLeft12,&TopRight12);
Swap(&TopLeft13,&TopRight11);
Swap(&TopLeft21,&TopRight23);
Swap(&TopLeft22,&TopRight22);
Swap(&TopLeft23,&TopRight21);
Swap(&TopLeft31,&TopRight33);
Swap(&TopLeft32,&TopRight32);
Swap(&TopLeft33,&TopRight31);
Swap(&MidLeft1,&MidRight3);
Swap(&MidLeft2,&MidRight2);
Swap(&MidLeft3,&MidRight1);
Swap(&BottomLeft11,&BottomRight13);
Swap(&BottomLeft12,&BottomRight12);
Swap(&BottomLeft13,&BottomRight11);
Swap(&BottomLeft21,&BottomRight23);
Swap(&BottomLeft22,&BottomRight22);
Swap(&BottomLeft23,&BottomRight21);
Swap(&BottomLeft31,&BottomRight33);
Swap(&BottomLeft32,&BottomRight32);
Swap(&BottomLeft33,&BottomRight31);
}

public void Flip_Hor_Ver()
{
Flip_hor();
Flip_ver();
}

}

here is the error i'm getting

:-Pointers may only be used in an unsafe context

can anybody help in how to implement pointer for my function and how to call from other methods of the same class.

thanks in advance,
Pavan.

Suman

MSDN is your friend: unsafe[^]

Do you want to know more?

Not getting the response you want from a question asked in an online forum: How to Ask Questions the Smart Way!

Hi,

it helped tough and I am able to fix the function definition... but the only other repeated error was

----: You can only take the address of unfixed expression inside of a fixed statement initializer.. wht is a fixed statement initializer and unfixed expression... i did went through MSDN, but not able to understand their definition and the way they r defining...

here is how i defined my methods

unsafe static void Swap(int *x, int *y)
{
int temp;
temp=*x;
*x=*y;
*y=temp;
}

unsafe public void Flip_Hor()
{
Swap(&TopLeft11,&BottomLeft31);
Swap(&TopLeft12,&BottomLeft32);
Swap(&TopLeft13,&BottomLeft33);
Swap(&TopLeft21,&BottomLeft21);
Swap(&TopLeft22,&BottomLeft22);
Swap(&TopLeft23,&BottomLeft23);.....
.
.
.
}

Are my method definitons are wrong?
or should i have to add anything more...

anotehr error is...

Method System.Windows.Forms.Form.CenterToParent not found.

I have implemented a form to take a value as a parameter to my program.... but in its defintion it is giving the above error. The same form is workin well in another project, but givin the above eroor in another project..any idea why it is like tht...

can anyone help me....

thanks in advance,

Suman

with a little reference into the Professional C#... i have resolved my problems....

thanks

Suman

I have this byte[] variable with an UNICODE encoded string. The string is not null terminated, but I know its size. What is the fastest way to convert the byte[] to a string?

Regards,
João Paulo Figueira
Embedded MVP

byte[] bytes;

string s = System.Text.UnicodeEncoding.Unicode.GetString(bytes);

you can optionally specify the size.

I'm curious now, i've looked at serialization and other encoding / decoding methods, but is there any simple way to type cast a simple object like an image or struct, into a set of bytes and back?

Or does it have to be done using serialisation?

Chrs

Cata

Actually I believe the .NET serialization is probably the easiest and quickest way of getting the task done.

If you want to do it by yourself you have to take care of quite a mess. For example to get the image from a byte array

MemoryStream ms = new MemoryStream(byte[]);
Image i = Image.FromStream(ms);

You can go the other way by doing i.Save(stream, encoding.... etc.)

I might be missing some quick and dirty way of doing this through use of unmanaged memory reading but you have to be careful with that.

I thought as much, but i was just thinking, as everything is represented as a collection of bytes, why can't you just declare a collection of bytes as an object (obviously error handle it for invalid format), or declare an object as a collection of bytes.

Are there any physical restraints on this?

Cata

Thank you! Smile | :)

Regards,
João Paulo Figueira
Embedded MVP

I've got a LOGFONT structure for a windows caption, and i'd like to pull the details from it relating to font family and size.

Font family I can get, that's not a problem, but there is no mention of the font size anywhere.

As the font size is related to the caption size only in terms of the captions minimum size, i know it's only tied in with the actualy font, but the height and width don't seem to have any bearing on the EM or Pixel size.

Is there some equation, or other route therof to obtain this information?

Cheers

Cata

[Edit: Height in the LOGFONT says it is EM-Height. The Hight in .NET font is line height. Am I right in assuming that the Logfont height would be used as .NET font size?]

hiii every body is there anyone who can help me in my problem
i have an application that is consist of a main screen with a main menu from that menu i open another forms, i found that the memory space my application reserve increase every time i open a form and close it

i mean that in the first time i open the program the memory space it take on the winows task manager 13,... k
after i open any form from the menu the size become 22,000 k closing the form and return to the main form the size of memory become 20,000 k but it doesn't return to its initial state

note : i found that when i minimize the application and maximize it again the memory return to its first state

---- my application contain too more graphics-----
can any body help me please

Im not sure what exactly is happening in your application. But...

Memory in a c# application is managed by .NET. Appearently you have a form that uses up a lot of memory. When "garbage collection" occurs the memory is freed. You can look into this if u are concerned about memory usage.

The garbage collector is at work. Its operation is non-deterministic (therefore you cannot workout when it will run). It will run when memory is low and generally when the application is idle. I wouldn't worry too much about it.

Do you want to know more?

Not getting the response you want from a question asked in an online forum: How to Ask Questions the Smart Way!

I got everything working fine in my .net remoting proggy. My question is, i want to make a single instance of my obj that my server can put data in and then hand it out to the clients. I dont know how to create a instance of the object from within my server, after it is already registered as a wellknowntype. i tryed using the code from my client to init a instance of the object but it just tells me that "the http something is already in use" i.e this code wont work on the server who registered the object.

ChannelServices.RegisterChannel( new HttpChannel() );<br />
				IRemoteObj obj = (IRemoteObj) Activator.GetObject(<br />
					typeof(IRemoteObj),<br />
					"http://localhost:8085/ObjURI"<br />
					);<br />

Thanks for your time.
Jesse

The Code Project Is Your Friend...

If you want to publish a specific instance of an object you should use RemotingServices.Marshal() instead of RegisterWellKnownServiceType().

Thanks alot. I figured it out from what you said. Very helpfull thanks.

Jesse

The Code Project Is Your Friend...

hi all,

i have a problem here and i hope to have a solution:

i am working on an online handwriting recognition project.
its idea that a user should have a pen-tablet and write on
it his text, my program should recognize what the user
writes. the problem that i have is that i don't know how
to catch the events of the tablet and how to retreive the
information from it.

on the mouse for example we have an event (onMouseDown)
and in this event we can retreive the X and Y position of
the mouse pointer and other information. i want for the
tablet to catch the event of putting the pen on the tablet
and i want to get all the information that are available
with this event such as the pressure of the pen and the
X,Y position of the pen pointer. does any body know how to
do this with C#????

help me please Frown | :(

thanks,