Why doesn't Process.WaitForInputIdle() work? - wpf

I am using Windows Automation to test my UI and am opening and closing processes. I want to have a valid WindowHandle, but Process.WaitForInputIdle() doesn't wait long enough. I have a work around, but don't understand why WaitForInputIdle() doesn't work.
Below is a small code snip:
Process = new Process
{
StartInfo =
{
WorkingDirectory = directory,
FileName = EXECUTABLE_FILE_NAME
}
};
Process.Start();
//Process.WaitForInputIdle() doesn't work,
//so will use a while loop until MainWindowHandle isn't IntPtr.Zero anymore,
//or until 10 seconds have elapsed
int count = 0;
while (Process.MainWindowHandle == IntPtr.Zero && count<100)
{
count++;
Thread.Sleep(100);
}
AppElement = AutomationElement.FromHandle(Process.MainWindowHandle);

As stated by Chaser324 in his comment, the answer to my question can be found here.
I basically need to add a call to Process.Refresh() inside of my 'while' loop.

Related

Make a while loop, loop for 1 second in Dart/Flutter

I am trying to make a while loop loop a statement exactly for one second after which it stops. I have tried this in DartPad, but it crashes the browser window.
void main(){
var count = 0.0;
bool flag = true;
Future.delayed(Duration(seconds: 1), (){
flag = false;
});
while (flag){
count++;
}
print(count);
}
Am I doing something wrong?
I like how you are trying to figure Futures out. I was exactly where you were before I understood this stuff. It's kind of like threads, but quite different in some ways.
The Dart code that you wrote is single threaded. By writing Future.delayed, you did not start a job. Its execution won't happen unless you let go of the thread by returning from this main function.
Main does not have to return if it is marked with async.
Two actions have to run "concurrently" to be able to interact with each other like you are trying to do. The way to do it is to call Future.wait to get a future that depends on the two futures. Edit: Both of these actions have to let go of execution at every step so that the other can get control of the single thread. So, if you have a loop, you have to have some kind of await call in it to yield execution to other actions.
Here's a modified version of your code that counts up to about 215 for me:
Future main() async {
var count = 0.0;
bool flag = true;
var futureThatStopsIt = Future.delayed(Duration(seconds: 1), (){
flag = false;
});
var futureWithTheLoop = () async {
while (flag){
count++;
print("going on: $count");
await Future.delayed(Duration(seconds: 0));
}
}();
await Future.wait([futureThatStopsIt, futureWithTheLoop]);
print(count);
}

How to add time delay to process more than 15 second in Actionscript?

So I have the following script to get all combination of an array :
'''
var value = new Array(40)
for (var i=0;i<value.length;i++){
value[i]=i;
}
var comb_list = getAllComb(value,24);
trace(comb_list)
function getAllComb(values:Array, r:int):Array{
var n = values.length;
var result = new Array();
var a = new Array(r);
// initialize first combination
for (var i = 0; i < r; i++) {
a[i] = i;
}
i = r - 1; // Index to keep track of maximum unsaturated element in array
// a[0] can only be n-r+1 exactly once - our termination condition!
var count = 0;
while (a[0] < n - r + 1) {
// If outer elements are saturated, keep decrementing i till you find unsaturated element
while (i > 0 && a[i] == n - r + i) {
i--;
}
result.push(a.slice())// pseudo-code to print array as space separated numbers
count++;
a[i]++;
// Reset each outer element to prev element + 1
while (i < r - 1) {
a[i + 1] = a[i] + 1;
i++;
}
}
return result;
}
'''
Running above script will get me:
Error: Error #1502: A script has executed for longer than the default timeout period of 15 seconds.
How to add time delay each 14 seconds passed so that I can run the script? So, after 14 seconds passed, the program will wait for 50ms then continue.
Any help appreciated.
So, there's a simple (well, pretty much so) and working example of how to separate the heavy calculations part from the main thread so the main thread (which also handles UI and external events like user input) would run smoothly, while being able to read the progress and the results of the heavy calculations going under the hood. It also is in a form of a single class, this could be a bit confusing (until you understand how it works) but still easy to handle and modify.
Although the background AVM goes along the same execution flow (code execution > graphics rendering > code execution > graphics rendering > and so on), there are no graphics to render hence there's no need to anyhow limit the code execution time. As a result Worker thread is not a subject to 15 seconds limit, which, somehow, solves the problem.
package
{
import flash.events.Event;
import flash.display.Sprite;
import flash.utils.ByteArray;
import flash.concurrent.Mutex;
import flash.system.Worker;
import flash.system.WorkerDomain;
public class MultiThreading extends Sprite
{
// These variables are needed by both the main and
// subservient threads and will actually point to
// the very same object instances, though from
// the different sides of this application.
private var B:ByteArray;
private var W:Worker;
private var M:Mutex;
// Constructor method.
public function MultiThreading()
{
super();
// This property is 'true' for the main thread
// and 'false' for any Worker instance created.
if (Worker.current.isPrimordial)
{
prepareProgress();
prepareThread();
startMain();
}
else
{
startWorker();
}
}
// *** THE MAIN THREAD *** //
private var P:Sprite;
private var F:Sprite;
// Prepares the progress bar graphics.
private function prepareProgress():void
{
F = new Sprite;
P = new Sprite;
P.graphics.beginFill(0x0000FF);
P.graphics.drawRect(0, 0, 100, 10);
P.graphics.endFill();
P.scaleX = 0;
F.graphics.lineStyle(0, 0x000000);
F.graphics.drawRect(0, 0, 100, 10);
F.x = 10;
F.y = 10;
P.x = 10;
P.y = 10;
addChild(P);
addChild(F);
}
// Prepares the subservient thread and shares
// the ByteArray (the way to pass messages)
// and the Mutex (the way to access the shared
// resources in a multi-thread environment
// without stepping on each others' toes).
private function prepareThread():void
{
M = new Mutex;
B = new ByteArray;
B.shareable = true;
B.writeObject(incomingMessage);
W = WorkerDomain.current.createWorker(loaderInfo.bytes);
W.setSharedProperty("message", B);
W.setSharedProperty("lock", M);
}
// Starts listening to what the background thread has to say
// and also starts the background thread itself.
private function startMain():void
{
addEventListener(Event.ENTER_FRAME, onFrame);
W.start();
}
private var incomingMessage:Object = {ready:0, total:100};
private function onFrame(e:Event):void
{
// This method runs only 20-25 times a second.
// We need to set a lock on the Mutex in order
// to read the shared data without any risks
// of colliding with the thread writing the
// same data at the same moment of time.
M.lock();
B.position = 0;
incomingMessage = B.readObject();
M.unlock();
// Display the current data.
P.scaleX = incomingMessage.ready / incomingMessage.total;
P.alpha = 1 - 0.5 * P.scaleX;
// Kill the thread if it signalled it is done calculating.
if (incomingMessage.terminate)
{
removeEventListener(Event.ENTER_FRAME, onFrame);
W.terminate();
B.clear();
B = null;
M = null;
W = null;
}
}
// *** THE BACKGROUND WORKER PART *** //
// I will use the same W, M and B variables to refer
// the same Worker, Mutex and ByteArray respectively,
// but you must keep in mind that this part of the code
// runs on a different virtual machine, so it is the
// different class instance thus its fields are not
// the same quite as well.
// Initialization.
private function startWorker():void
{
W = Worker.current;
M = W.getSharedProperty("lock");
B = W.getSharedProperty("message");
// Before starting the heavy calculations loop
// we need to release the main thread which is
// presently on W.start() instruction. I tried
// without it and it gives a huuuge lag before
// actually proceeding to intended work.
addEventListener(Event.ENTER_FRAME, onWorking);
}
private function onWorking(e:Event):void
{
removeEventListener(Event.ENTER_FRAME, onWorking);
var aMax:int = 10000000;
// Very very long loop which might run
// over the course of several seconds.
for (var i:int = 0; i < aMax; i++)
{
// This subservient thread does not actually need to
// write its status every single loop, so lets don't
// explicitly lock the shared resources for they
// might be in use by the main thread.
if (M.tryLock())
{
B.position = 0;
B.writeObject({ready:i, total:aMax});
M.unlock();
}
}
// Let's notify the main thread that
// the calculations are finally done.
M.lock();
B.position = 0;
B.writeObject({ready:i, total:aMax, terminate:true});
M.unlock();
// Release the used variables and prepare to be terminated.
M = null;
B = null;
W = null;
}
}
}
The error is not related to your script needing a time delay, the problem is your while loops are making your script unresponsive for more than 15 seconds, triggering the script timeout error. Action Script only allows 15 seconds for your script to execute.
Your first while loop looks problematic, and I'm unclear how the value of a[0] changes to end the loop. Add a break to the loop or make sure the condition changes to allow the loop to end, and you should solve your problem. You can also considering adding continue statements to your embedded while loops if they are only supposed to run one time after they find an unsaturated value.
Personally, since you are using ActionScript, I'd suggest using objects and listeners for value changes instead of iterating over arrays checking for changes.
You could also add a manual timeout for your while loop, but would need to include logic for it to pick up where it left off.
//Set timer to 14 seconds
timeout = getTimer() + 14000;
while(true && timeout > getTimer()){
trace("No Error");
}
If you were used Adobe Animate (Flash), you could change the "Script Time Limit" from Publish setting page.

Dart - getting 'Malformed message' in console when spawning multiple isolates

i'm new to dart and i'm trying to run multiple algorithms using isolates to more efficiently run them multiple times, however, when calling more than one function with Isolate.spawn i start getting 'Malformed message' in the console, it still works, but i would like to know why am i getting this message, also any help in improving the code is welcome since i'm still learning the intricacies of using isolates
stressTest()
{
ReceivePort rpDouble = new ReceivePort();
ReceivePort rpString = new ReceivePort();
ReceivePort rpInteger = new ReceivePort();
int counter = 0;
int tempoTotal = 0;
rpDouble.listen((data) {
counter++;
tempoTotal += data; //data is a stopwatch.toMilliseconds
setState(() { //updating the "progress" and the time it took to run the algorithm in the ui
test = counter.toString() + '%';
_counter = tempoTotal.toString();
});
});
rpInteger.listen((data){
counter++;
tempoTotal += data;
setState(() {
test = counter.toString() + '%';
_counter = tempoTotal.toString();
});
});
rpString.listen((data){
counter++;
tempoTotal += data;
setState(() {
test = counter.toString() + '%';
_counter = tempoTotal.toString();
});
});
for(int i = 0; i < 5; i++) {
Isolate.spawn(DoubleTest, rpDouble.sendPort);
Isolate.spawn(StringStress, rpString.sendPort);
Isolate.spawn(integerTest, rpInteger.sendPort);
}
}
}
the DoubleTest, StringStress and IntegerTest are functions that return a stopwatch.toMilliseconds integer to the sendPort.
Thanks in advance, any help is appreciated
This happens when you want to see the Performance App. However, during the Reload app, resyncing the data results in flutter performance not getting an address or interrupting the progress reader leading to that message. This does not affect the application or your application error. If you need to read "Memory usage" or "frame rendering times" then just restart the IDE and start again.
As your code is running fine, so you don't need to worry much about the error. However,try reformatting your code to avoid this error message.
I had a similar problem in my program. Just saving the file before 'hot restart' did the job.

NAudio trimming mp3 file

I'm trying to trim a mp3 file.
using this code:
private void TrimMp3(string open, string save)
{
using (var mp3FileReader = new Mp3FileReader(open))
using (var writer = File.Create(save))
{
var startPostion = TimeSpan.FromSeconds(60);
var endPostion = TimeSpan.FromSeconds(90);
mp3FileReader.CurrentTime = startPostion;
while (mp3FileReader.CurrentTime < endPostion)
{
var frame = mp3FileReader.ReadNextFrame();
if (frame == null) break;
writer.Write(frame.RawData, 0, frame.RawData.Length);
}
}
}
"open" is the file I'm trimming and "save" is the location I'm saving.
The trimming works but not fully. The new file does start from 60 seconds but it keeps going and not stopping at 90 seconds. For example if the file is 3 minutes it will start at 1 minute and end at 3. Its like the while is always true. What am I doing wrong here?
Thanks in advance!
I have no idea what your Mp3FileReader is doing there. But your while loop looks odd. Does mp3FileRead.ReadNextFrame() also change mp3FileReader.CurrentTime ? If not then there is your problem.
You should atleast do mp3FileReader.CurrentTime + 1Frame. Otherwise your currenttime is never changed and loop will always be true
In NAudio 1.8.0, Mp3FileReader.ReadNextFrame does not progress CurrentTime, although I checked in a fix for that recently.
So you can either get the latest NAudio code, or make use of the SampleCount property on each Mp3Frame to accurately keep track of how far through you are yourself.

Is it safe to abort this file-searching thread?

First, the code:
lblFileNbr.Text = "?/?";
lblFileNbr.ToolTipText = "Searching for files...";
lock(_fileLock)
{
_dirFiles = new string[0];
_fileIndex = 0;
}
if(_fileThread != null && _fileThread.IsAlive)
{
_fileThread.Abort();
}
_fileThread = new Thread(() =>
{
string dir = Path.GetDirectoryName(fileName) ?? ".";
lock (_fileLock)
{
_dirFiles = GetImageFileExtensions().SelectMany(f => Directory.GetFiles(dir, f, _searchOption)).OrderBy(f => f).ToArray();
_fileIndex = Array.IndexOf(_dirFiles, fileName);
}
int totalFileCount = Directory.GetFiles(dir, "*.*", _searchOption).Length;
Invoke((MethodInvoker)delegate
{
lblFileNbr.Text = string.Format("{0}/{1}", NumberFormat(_fileIndex + 1), NumberFormat(_dirFiles.Length));
lblFileNbr.ToolTipText = string.Format("{0} ({1} files ignored)", dir, NumberFormat(totalFileCount - _dirFiles.Length));
});
});
_fileThread.Start();
I'm building a little image-viewing program. When you open an image, it lists the number of files in the same directory. I noticed when I open an image in a directory with a lot of other files (say 150K), it takes several seconds to build the file list. Thus, I'm delegating this task to another thread.
If, however, you open another image before it finishes searching for the files, that old count is no longer relevant, so I'm aborting the thread.
I'm locking _dirFiles and _fileIndex because I want to add some Left and Right key functionality to switch between photos, so I'll have to access those somewhere else (but in the UI thread).
Is this safe? There seems to be dozens of methods of dealing with threads in C# now, I just wanted something simple.
fileName is a local variable (which means it will be "copied" into the anonymous function, right?), and _searchOption is readonly, so I imagine those 2 are safe to access.
> Is it safe to abort this file-searching thread?
The short answer is NO!
It is almost never safe to abort a thread, and this advice applies even more when you might be executing native code.
If you can't cooperatively exit fast enough ( because it is your call to Directory.GetFiles that takes time ), your best bet is to abandon the thread: let it finish cleanly but ignore its results.
As always, I recommend reading Joe Albahari's free ebook
It isn't safe to abort the thread using Thread.Abort(). But you could instead implement your own abort which could allow you to safely bring the thread to a close in a controlled fashion.
If you use EnumerateFiles instead of GetFiles, you can loop through each file as you increment a counter to get the total number of files while checking a flag to see if the thread needs to abort.
Calling something such as this in place of your current GetFiles().Length:
private bool AbortSearch = false;
private int NumberOfFiles(string dir, string searchPattern, SearchOption searchOption)
{
var files = Directory.EnumerateFiles(dir, searchPattern, searchOption);
int numberOfFiles = 0;
foreach (var file in files)
{
numberOfFiles++;
if (AbortSearch)
{
break;
}
}
return numberOfFiles;
}
You could then replace
_fileThread.Abort();
with
AbortSearch=true;
_fileThread.Join();
You'll achieve what you are with the current Thread.Abort(), but you will allow all threads to end cleanly when you want them to.

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