Re: Scroll + DrawImage Help - C# Discussion Boards

Christian Graus1-Feb-05 17:02

Christian Graus

1-Feb-05 17:02

Use DrawImage to draw only the bit you can see, instead of all of it. In theory it shouldn't matter ( I don't think ), but in practice it obviously does, as the size of an image is having an effect in your code.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

jk chan1-Feb-05 17:51

jk chan

1-Feb-05 17:51

Thanks for ur reply.

Can u explain it more . u means that there is no solution to this problem ? Frown | :(

but when i opening a large image with internet explorer or paint , i can scroll the image smoothly.

So i strongly belive that there is a solution to this.

Regards
Krishnan

If u can Dream... U can do it

Christian Graus2-Feb-05 9:05

Christian Graus

2-Feb-05 9:05

I am saying that instead of using a transform, you should just draw the bit you want to see. Most DrawImage functions take a rect that defines the part of the bitmap to draw. Use them.

Christian

I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer

Delimiters While Reading Text Files

Robert Rohde1-Feb-05 20:32

Robert Rohde

1-Feb-05 20:32

Have you tried using a PictureBox setting it SizeMode to AutoSize and just let the user control handle the scrolling with AutoScroll set to true?

If thats not working you should avoid using TranslateTransform as its a heavy function. If you pass negativ coordinates to your DrawImage function it should also work (as everything which cannot be drawn is simply clipped away). And dont use DrawImage, use DrawImageUnscaled instead (unless you need to scale).

Anonymous1-Feb-05 13:35

1-Feb-05 13:35

I have a program that currently reads a text file line by line and compares it against another string. However, my word list is all of a sudden separated by, not line breaks, but spaces. So, how would I instead check each string delimited by the spaces?

In case this helps, it's a word game that checks if a word is, in fact, a word.

Robert Rohde1-Feb-05 20:35

Robert Rohde

1-Feb-05 20:35

Depends on how long your list is Smile | :)

If its rather short just read the whole line and use Split(' ') to split it into seperated chunks. If its really large you will have to read it char by char, build up a string for each word until you find a space.

spif20011-Feb-05 20:42

spif2001

1-Feb-05 20:42

stringFromFile;
char[] delim = new char[1];
delim[0] = ' ';
string[] words = stringFromFile.Split(delim);
foreach(string s in words)
{
//check word
}

hope it helps - sounds strange, that it should replace line breaks with whitespaces

-spif2001

Anonymous2-Feb-05 4:21

2-Feb-05 4:21

Thanks. That may help.

This would be even easier: DO you know of any programs that can replace ' ' with line breaks? Word sure can't :/

Dave Kreskowiak2-Feb-05 4:35

Dave Kreskowiak

2-Feb-05 4:35

You'd have to write it. I don't know of any app that would convert spaces to CRLF's.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Sean Michael Murphy2-Feb-05 6:48

Sean Michael Murphy

2-Feb-05 6:48

System.IO.StreamReader sr = new System.IO.StreamReader(@"c:\test.txt");<br />
string   data = sr.ReadToEnd().Replace(" ", "\r\n");

Anonymous2-Feb-05 10:11

How do i use lock(List.SyncRoot) properly in a collection?

2-Feb-05 10:11

ALL PRAISES TO YOU, SEAN MICHAEL MURPHY! That worked _beatifully_. Thank you so much!

FocusedWolf1-Feb-05 13:17

FocusedWolf

1-Feb-05 13:17

Ok, situation as such...have a collection and it extends collectionbase.

this is how all of my functions go, in their most simple form...all code in (welcoming?) arms of a lock with the intention of making my control threadsafe.

public void Add(string text)
{
lock(List.SyncRoot)
{
List.Add(new SimpleListItem(text));
}
}

When i start adding items to the control with both a thread, and at same time syncheroussly...the control freezes up.

I think at that point its stuck in some kind of race condition because conflicting locks are preventing anything from getting into the collection for infinity and beyond :P

This leads me to my question:

Where do i put lock(List.SyncRoot)? When i comment out that line from my add function the control goes fine...

Re: How do i use lock(List.SyncRoot) properly in a collection?

Robert Rohde1-Feb-05 20:38

Robert Rohde

1-Feb-05 20:38

You should not alter a control from another thread than it was created in. Read in the MSDN about the Invoke method of the Control class. It delegates calls into the right thread. By doing so you even wont need to synchronize the calls anymore.

Re: How do i use lock(List.SyncRoot) properly in a collection?

Anonymous2-Feb-05 3:03

2-Feb-05 3:03

Thx for clearing that up for me.

Logon/Logout Methods?

spacebass50001-Feb-05 13:15

1-Feb-05 13:15

I have a program that is run via Task Scheduler as a given user. For sake of argument, we'll call this user "backup".

When my program runs via the Task Scheduler, I have it pop up an input box on a certain event (backup failure) and ask the user (apparently "backup", the user who the task is running as) if he/she would like to retry to the backup.

So lets say the user "bob" is logged on, hell, lets look at the case when bob is logged on as well as when nobody is logged on.

If my task runs and has a problem, the input box is lost due to "backup" not being logged in. Yet it still shows up in my process listing...

So I need a way to have my program (which is running with administrative privileges as they are needed for backup reasons) to log the current user off (or not if nobody is logged on) and log backup on prior to running its backup jobs.

Now I know that this sounds like a hokey thing to do with regards to security. I'm not fond of doing it this way but it is what has been asked of me. To be honest, I plan on implementing a toggle for this functionality.

Thanks...

Dave Kreskowiak2-Feb-05 1:55

Dave Kreskowiak

2-Feb-05 1:55

Logs the user off?! If an application did that to me unexpectedly, the first thing I'd do is uninstall it, burn the CD's it came on, then mail the molten pile of (*$^##& back to the company that wrote it explaining why.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

spacebass50002-Feb-05 2:20

2-Feb-05 2:20

haha... no doubt man

again, not my idea, just need to know how to implement it or work around it

any helpful suggestions?

spacebass50002-Feb-05 3:41

2-Feb-05 3:41

My thoughts are to simply make this a service and be done with it...

Dave Kreskowiak2-Feb-05 4:34

Dave Kreskowiak

2-Feb-05 4:34

Well, the normal way to do this would be to run the service under an account that has the appropriate rights to the resource you need and not supply any user interface what-so-ever. If the backup fails, you can't just pop up a dialog because you don't know if there is anyone logged in or not to see it. You can't just log off the current user, then log on some other user either. It would REALLY SUCK if you forced a user off without saving his changes (if he/she wanted them saved). You simply can't control how that is done. You will either have to FORCE the user off, losing any changes he might need saved or site there and wait for the user to save changes. Oh!! There's a problem there. The user can always click Cancel to saving any changes. This will also have the effect of canceling the logoff too!

A better method would be to have a second application running in the system tray that communicates with the service and supplies notifications and interactions through the tray icon (you can use .NET Remoting for communication part.) This application would then put up the interface to ask the user if they would like to retry the backup and tell the service to retry if it needs to.

I would also suggest going back to the people who are requesting this junk and telling them that what they want is not practical and modify the specifications to, God forbid, accomodate the needs of the USER, and works within the functional limits of Windows.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

spacebass50002-Feb-05 5:10