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I need to display multiple images from a folder by using four image boxes.
The pictures should display according to change. I was put "FileSystemWatcher" to identify the file change and display images according to that. but when execution it does't go inside the "public void OnChanged" function.
but no image will display.
does anyone know how to solve this issue. or any other method for display latest four images from a folder..
Thank you.
This is my code
public partial class Form1 : Form<br />
{<br />
FileSystemWatcher watcher = new FileSystemWatcher();<br />
<br />
public Form1()<br />
{<br />
<br />
InitializeComponent();<br />
<br />
watcher.Path = @"f:\My FYP\FYP_Update 2.1\New_Traffic_Pics";<br />
watcher.Created += new FileSystemEventHandler(OnChanged);<br />
LoadLatestImage();<br />
<br />
}<br />
<br />
public void LoadLatestImage()<br />
{<br />
<br />
<br />
<br />
watcher.NotifyFilter = NotifyFilters.LastWrite;<br />
<br />
watcher.Filter = "*.jpg";<br />
<br />
<br />
}<br />
<br />
public void OnChanged(object source, FileSystemEventArgs e)<br />
{<br />
pictureBox1.ImageLocation = e.FullPath;<br />
}<br />
<br />
<br />
private void Form1_Load(object sender, EventArgs e)<br />
{<br />
<br />
}<br />
<br />
private void pictureBox1_Click(object sender, EventArgs e)<br />
{<br />
<br />
}<br />
<br />
private void timer1_Tick(object sender, EventArgs e)<br />
{<br />
LoadLatestImage();<br />
}<br />
<br />
<br />
}
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I agree.
Watch out for EnableRaisingEvents.
And please use PRE tags, not CODE tags, to preserve formatting when posting code snippets. It is in the guidelines.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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You might want to review this article series regarding FileSystemWatcher.
FileSystemWatcher - Pure Chaos (Part 1 of 2)[^]
FileSystemWatcher - Pure Chaos (Part 2 of 2)[^]
.45 ACP - because shooting twice is just silly
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"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001
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Hi everyone
I have a question about creating a click event for a class. Thing is I have created a UserControl which takes images and arranges them dynamically given certain circumstances. This control uses a list of 'Viewports' (basically rectangles which carry an image). I would like to create an event for this Class 'Viewport'. Currently i use the click event of UserControl and loop through the list, checking the regions of these viewports. I thought I could do better than this and give each port it's own event without having to loop. Is this possible? I was thinking in the direction of an API, but all ideas are welcome.
Thanks
Steven Solberg
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Steven Solberg wrote: This control uses a list of 'Viewports' (basically rectangles which carry an image).
Could each of them be a UserControl?
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Hmmm, I could give that a shot I guess. Certainly would fix the issue about the click event. I however don't know how that would affect the rest of my application. But i'll let you know. Thanks for the tip
Steven
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I added the inheritance from UserControl for the Viewport Class and added the click event. Ran a simple test with a messagebox and it works  Or at least sort of. This fix totally screwed up my threads, but i'll sort that out later. Thank you very much
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Why a UserControl? why not just a Panel? or, God forbid, a PictureBox?
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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:: shrugs :: Hadn't had any coffee at that point?
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if your view ports are not real Controls in the Windows sense, then they are contained in one, probably the UserControl itself. So you could use its Click event, and apply a filter, something like:
protected override void OnClick(object sender, MouseEventArgs e) {
Point pt=e.Location;
foreach(ViewPort vp in viewPorts) {
if (vp.Bounds.Contains(pt) && ViewPortClick!=null) ViewPortClick(vp, e);
}
}
That way, you don't modify your UserControl design, don't add Controls, don't spend memory, and don't slow down its rendering; it would dispatch your click somewhat slower if you were to have dozens or hundreds of ViewPorts, however that would be bad for rendering already.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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Perhaps it would be best if I widen my explanation 
The Viewports in the UserControl are somewhat controls themselves, but I don't need all the overhead of anchors and such. In other words, I made something like a listview with a dynamic hierarchical design. This enables me to zoom in on a picture, draw on it and pass these drawn points upward to the source viewport. The control also knows what kind of line is drawn (The purpose of this program is a facial analysis tool, lines between eyes and such). Then I need to rotate and translate them, to match certain patterns. All of this dynamic stuff works perfectly, only thing is that when the number of ports increases, the responses to mouseclicks 'degrade'. This is why I wanted to use a click event. That forloop monstrosity is what I am using now . If only i could post a picture, that would explain a whole lot...
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Steven Solberg wrote: the responses to mouseclicks 'degrade'
what does that mean?
response time increasing unacceptably? it shouldn't, I see no reason, you need a hit-search like the one I've shown, that should not take up much cycles!
image flickering? it shouldn't, no need to repaint anything.
so how does it degrade?
FWIW: you can store an image on any of a number of free sites, then post a link here.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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Yes you're right... It shouldn't. I can't find any reason for it though. Problem is that I have to keep the mousebutton down for a few milliseconds instead of just clicking it.
I have put the image on one of my repositories. You can log in as 'guest', password is also 'guest'. Hope you don't mind I upload it this way.
The control uses a number of different viewmodes. The one you're seeing in the image is the treeview for subsections. These subsections are linked to their sources by drawing a rectangle on the original picture. It then saves this image and the offset to it's source. So I can calculate the points on the source when lines are drawn on a subsections. Perhaps an important detail: I use a number of threads and an FSM to power the changing of these viewmodes. When this happens, every viewport gets a thread to make it change location and size, so it appears to be moving. This is limited at 30fps though.
http://solberg.sin.khk.be/repos/PublicRep/[^]
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so it is NOT a MouseClick issue, it is a "do many things while mouse is down" problem.
Not sure what the picture should tell me. All I see is a couple of images, some very similar or identical.
Some thoughts:
1.
While the mouse is down (I assume inside a MouseMove handler), maybe you are repeating a lot of calculations over and over, which only need to happen once, and could be moved to the actual MouseDown handler.
2.
Using multiple threads may cause delays; it all depends on how you organize things. If you have more threads than cores, and all of them are "ready" meaning they have some non-blocking job, they will be switched in and out based on the time slice which probably is 1 or 2 system ticks (that would be 10 to 30 milliseconds), a fairness principle.
3.
Watch your CPU load; if Task Manager never comes close to 100%, then more threads might help. If you are close to 100%, then many things are possible:
a. you are performing unnecessary operations (e.g. repainting an image that hasn't changed at all)
b. you have polling loops; that is the perfect way to waste CPU power
c. you have small jobs (less than 0.1 millisecond); thread switching becomes dominant cost
d. your implementation is OK, maybe the job is big, or your concept is flawed.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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The pictures in blue are the subsections I was talking about. These are extracts from the picture at the left of them. So by drawing a line on one of the blue pictures, a line is drawn in the same physical place on the yellow picture, just more precise. The other yellow pictures are just other independant pictures, which in turn can also have subsections. I already considered the MouseMove issue, but I programmed my control not to react when threads are still running. The threads I mentioned only move the viewports. Between mouseclicks. So that shouldn't be a problem. Calculations are only run when the mouse is released. I don't even use MouseMove and I watch the use of OnPaint very carefully My CPU isn't doing any overtime either. around 10% mostly, spikes of 50% (Both cores that is)
I really appreciate the effort you put in my problem though, so thanks
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You're welcome.
I have three points for you:
1.
While several people, myself included, offered answers to your original question, I feel you still have problems, though I don't know what your problem is. If you want help, provide a context description (that you have), a specific scenario (a simple one is best), and its symptoms, emphasizing where it deviates from what you expect.
2.
and please explain "degrades". is it quality? or what? try to be precise, it improves your chances for getting useful suggestions.
3.
One more thing: I strongly suggest you read this little article of mine[^] and tell me which of the rules mentioned there you are violating, if any.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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The problem is persistent, it does not appear at specific times or actions nor series of actions. When clicking (MouseUp) one of the viewports, I have to keep my mousebutton down for a small time. In other words; My mouseclicks are not always recognized, or so it seems. This bug does not happen when I hold down the mousebutton for a small time and then release it, instead of a short click. Other than that, all is working perfectly. But it is very annoying to have to click several times or wait, to get a response from the control. This covers point 1 and 2 of your inquiry i guess. I read the article and I can proudly say that my animation is made by the rules  Except the use of brushes, could that be it?
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OK. Now we are getting tangible information. I think one of your mouse handlers is taking too long for comfort. You should not have anything blocking in there, such as Thread.Sleep; Thread.Join; and many more.
This is what I recommend to improve observability:
- add logging to all mouse event handlers; say one log on entry, one log on exit.
- make a single log method to do the actual logging, it should take a single string parameter identifying which method is calling it
- make sure the log will include a timestamp, up to the millisecond (*);
- log to one or several outputs, including a file so you have a chronological log.
Here is an example that I use often; it is based on a free running stopwatch (DateTime.Now isn't accurate enough as I explained here[^]):
public static void log(string s) {
long msec=myStopWatch.ElapsedMilliseconds;
int TID=Thread.GetCurrentThread().ManagedThreadId;
s=msec.ToString("D8")+" ["+TID.ToString("X2")+"] "+s;
Console.WriteLine(s);
File.AppendText(logFilePath, s+Environment.NewLine);
}
public void MouseDown(...) {
log("MouseDown begin");
...
log("MouseDown end");
}
If you don't touch GUI Controls in the log method, you can call it also from any thread you like to track. If it needs GUI access, you need Invoke stuff as explained here[^], but I guess you know all that.
Now run and watch the log it generates. Look for handlers taking more than 20 milliseconds; and for strange sequences of events.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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I'll try that log first thing tomorrow. My Belgian clock says it's almost 10pm, so I'm calling it a day
About the threads in MouseEvents... I fixed that already. Putting a sleep or join there would indeed slow everything down. So I am using a firing Thread which in turn calls the actual worker, so the main thread can continue without having to wait. The worker thread does have a join, but main is not affected by it. The firing thread and workers can be killed by setting a single boolean when necessary, but this does not occur. Just safety with a timeout. But like I said, I will use the log tomorrow and let you know asap. Good night
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Not sure what I should expect with firing threads and worker threads and the like; sooner or later you have to synchronize, unless you applied a self-synchronizing data scheme, which is quite tricky and vulnerable to occasional mishaps. Even more reason to incorporate good logging...
See you.
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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Got it! I included an invalidate in the MouseMove event. This is necessary to draw a rectangle when dragging the mouse, but I put in the wrong conditions. This way it also fires when I am not drawing any rectangles, but just move the mouse. I hope this will solve my problem, but I am confident it will Thank you very much guys.
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Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read formatted code with indentation, so please use PRE tags for code snippets.
I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).
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Nope... That wasn't it, but I know were to look now...
I added a simple Console.WriteLine in my MouseUp event. Seems that this always fires when I click a viewport. But it looks AS IF it is not acknowledged. The viewport does not invalidate. So there has to be a certain timing-issue which prevents it from updating the control...  I'll let you know when I find it.
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Oooowwww... I made a deadly mistake and found the following.
I logged the use of my Morph-threads. These are assigned to a viewport to animate it's movement. So when I have four ports, four threads are launched, each controlling the movement of it's port. When I add pictures to my control by applying a Set (this is another class to interact with a database, but that's not important), every picture in this Set is added by a function AddViewport. This function also updates the control to adjust it's viewmode. Thus reorganising the pictures. But it does this every time a picture is added. So in my example 4 times. I noticed in the log that ten threads were running. And that makes sense! Because when the first picture is added, it will be the only one, so one thread is launched. Next time it will launch two. And so on. And since 1+2+3+4=10. This is perfectly logical. I should have noticed this before...  Since my viewports seemed to juggle around when adding them. This is explained by the multiple threads moving the same port. Chances are that this injects dead threads and causes my control to stop responding, since I monitor the number of threads and while this is not zero, the input is blocked. Thanks Luc Pattyn, I would never have found this without your idea about the log.
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hey
Dim picdata As PictureBox
For x = 0 To Panel1.Controls.Count - 1
picdata = Panel1.Controls.Item(x)
next
how can i do this in c#
t'hanks
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