I'm trying to let a program post a bunch of text. The user enters text, the amount of messages and how fast these must be delivered. While the program is busy, the button text needs to be "Stop" instead of "Start". When you press the button to force it to stop after you've initially launched it, the text changes back to "Start", but this doesn't happen when the program stops after the given amount of messages are delivered, even though the code is in place and doesn't generate an error.
I have a feeling that this is because of the text not updating for some reason. I've tried to flush it with Invalidate() and Update(), but this isn't working. How to fix this?
Here is the code:
private void button1_Click(object sender, EventArgs e)
{
if (button1.Text == "Start")
{
isEvil = true;
button1.Text = "Stop";
Thread t = new Thread(StartTyping);
t.Start(textBox1.Text);
}
else
{
isEvil = false;
button1.Text = "Start";
}
}
private void StartTyping(object obj)
{
string message = obj.ToString();
int amount = (int)numericUpDown2.Value;
Thread.Sleep(3000);
for (int i = 0; i < amount; i++)
{
if (isEvil == false)
{
//////This does NOT work
//button1.Text = "Start";
//button1.Invalidate();
//button1.Update();
//button1.Refresh();
//Application.DoEvents();
break;
}
SendKeys.SendWait(message + "{ENTER}");
int j = (int)numericUpDown1.Value * 10;
Thread.Sleep(j);
}
}
You have four answers telling you to update UI stuff from the UI thread, but none of them address the logic flow problem with your code.
The reason why it doesn't happen is because it only happens in the for-loop when isEvil is false. When does isEvil get set to false? Only when you click "Stop", and nowhere else.
If you want the button to go back to "Start" after the thread finishes, without clicking "Stop", then you need to add code after the loop to do that, independent of the value of isEvil: (piggybacking off of VoidMain's answer)
private void StartTyping(object obj)
{
string message = obj.ToString();
int amount = (int)numericUpDown2.Value;
Thread.Sleep(3000);
for (int i = 0; i < amount; i++)
{
if (isEvil == false)
{
if (button1.InvokeRequired)
{
button1.BeginInvoke( new Action(() => { button1.Text = "Start"; }) );
}
else
{
button1.Text = "Start";
}
break;
}
SendKeys.SendWait(message + "{ENTER}");
int j = (int)numericUpDown1.Value * 10;
Thread.Sleep(j);
}
if (button1.InvokeRequired)
{
button1.BeginInvoke( new Action(() => { button1.Text = "Start"; }) );
}
else
{
button1.Text = "Start";
}
}
Now you have duplicated code, so you might want to split it off into a separate method.
You need to be on the UI thread to update the UI.
Try something called the SynchronizationContext. There are plenty of examples when you google it.
If you're in WPF or Silverlight, you could use the Dispatcher. Again, lots of examples if you search those keywords in google or StackOverflow.
You must update your controls from the UI thread. This is how you would do it for winforms.
for (int i = 0; i < amount; i++)
{
if (isEvil == false)
{
button1.Invoke(new Action(() => button1.Text = "Start"));
break;
}
SendKeys.SendWait(message + "{ENTER}");
int j = (int)numericUpDown1.Value * 10;
Thread.Sleep(j);
}
This will block till button1 get's its text updated. If you don't want it to block, replace Invoke with BeginInvoke
Your best bet is to use a BackgroundWorker. It's a bit too wieldy to add a concise example here but there's a decent tutorial from O'Reilly
Something like this (not tested) should work:
private void StartTyping(object obj)
{
string message = obj.ToString();
int amount = (int)numericUpDown2.Value;
Thread.Sleep(3000);
for (int i = 0; i < amount; i++)
{
if (isEvil == false)
{
if(button1.InvokeRequired)
{
button1.BeginInvoke( new Action(() => { button1.Text = "Start"; }) );
}
else
{
button1.Text = "Start";
}
break;
}
SendKeys.SendWait(message + "{ENTER}");
int j = (int)numericUpDown1.Value * 10;
Thread.Sleep(j);
}
}
Related
I have a class to load some data from a file and a progress bar form to show the process. My class uses a for loop to load data with a selected buffer size and sets the progress bar value in each loop.
I want to add a cancel and pause button to my form, but when my class starts loading data, the form buttons dont work.
I tried using different threads but they can't have access to same element.
How can I make it so that buttons work when data is loading?
Note: user can select the read type so there are different methods for each type(double,int,byte)
here is my load function:
for (int count = 0; count < (FileSize / LoadBufferSize); count++)
{
if (_check_click == 2)
{
return convertedData;
}
else if(_check_click==1)
{
return new Int16[1];
}
else
{
int j = 0;
for (int i = 0; i < fileContent.Length; i++)
{
try
{
fileContent[i] = br.ReadInt16();
}
catch (EndOfStreamException)
{
loadflag = 1;
contentSize = i;
break;
}
}
for (int k = 0; k < contentSize; k += ReSampleRate)
{
try
{
convertedData[(count * fileContent.Length / ReSampleRate) + j] = fileContent[k];
j++;
}
catch (IndexOutOfRangeException)
{
MessageBox.Show("could not load the file completely");
goto lable;
}
catch
{
MessageBox.Show("something went wrong");
}
}
progress = ((count + 1) * fileContent.Length ) / (FileSize / 100);
barForm.SetBar((int)progress);
}
}
lable:
{
return convertedData;
}
This might be helpful.
public class Form1 : Form
{
private Queue<string> _items = new Queue<string>(new [] { "A", "B", "C" });
private Button _startButton = new Button() { Text = "Start", Top = 8, Left = 4, Height = 24, Width = 100 };
private Button _pauseButton = new Button() { Text = "Pause", Top = 32, Left = 4, Height = 24, Width = 100 };
private bool _paused = false;
public Form1()
{
_startButton.Click += (s, e) => this.Process();
_pauseButton.Click += (s, e) => _paused = true;
this.Controls.Add(_startButton);
this.Controls.Add(_pauseButton);
}
private void Process()
{
if (!_paused && _items.TryDequeue(out string text))
{
Console.WriteLine(text);
this.Invoke(() => this.Process());
}
}
}
The key thing here is that the private void Process() method has a recursive call to itself through the .Invoke method. This keeps running Process so long as there are items in the queue, but it also lets other events occur in the meanwhile, so if someone clicks the Pause button then the Process method will stop running.
There is no for loop. Just a repeating Process method that responds to any changes in state.
I have been trying to work out why my background worker is 'finishing' its work when there is still a lot for it to do. I am actually in the process of refactoring the code for this app, so it did work in the past, but now I am unable to figure out what has gone wrong.
Specifically, the app should open Outlook and then perform a few checks. However, the background worker exits straight after Outlook is opened for no apparent reason (as you will se below there is still plenty of processing to be done).
This appears to be happening early on in the Start() method, directly after calling Process.Start() on Outlook.exe.
The code runs in this order:
calling the background worker - this was the user's choice from a radio set
....
else if (radioButton5.Checked == true)
{
textBox1.Text = "Please wait while your session restarts";
pageControl1.SelectedIndex = 10;
backgroundReset.RunWorkerAsync();
}
The do-work method
public void backgroundReset_DoWork(object sender, DoWorkEventArgs e)
{
backgroundReset.WorkerSupportsCancellation = true;
Session.Reset();
}
the reset session method starts by killing the current session ...
public static void Reset()
{
KillSession();
System.Threading.Thread.Sleep(5000);
Start();
// THE BACKGROUNDWORKER EXITS BEFORE HERE!
if (IsLoggedIn() == false)
{
return;
}
else
{
// Make sure Lync is open before finishing the process ...
var j = 0;
GetSession(Init.servers);
j = 0;
var checker = false;
checker = ProcessHandler.CheckRunning("lync.exe");
while (checker == false)
{
if (j == 100)
{
break;
}
Thread.Sleep(500);
checker = ProcessHandler.CheckRunning("lync.exe");
j++;
}
}
}
As you can see from the comment, the backgroundworder is calling RunWorkerCompleted way before the Reset() method has finished executing.
Below are the other methods called (kill, logoff, start):
KillSession logs the session of and then makes sure it is logged off
private static void KillSession()
{
if (sessionId != null)
{
LogOff();
for (int i = 0; i < 150; i++)
{
if (IsLoggedIn() == true)
{
Thread.Sleep(500);
}
else
{
break;
}
}
}
}
LogOff sends a Cmd command to log off the current session
public static void LogOff()
{
string strCmdIn = "/C LOGOFF " + sessionId + " /SERVER:" + serverName;
Cmd.Exec(strCmdIn);
}
Start() Simply opens Outlook, causing a Citrix session to also start. The app is definitely launching Outlook, but after that it doesn't reach either of the for statements - the BackgroundWorker just exits.
public static void Start()
{
Process.Start(appDataCitrix + "Outlook.exe");
for (int i = 0; i < 15; i++)
{
if (IsLoggedIn2() == false)
{
Thread.Sleep(1000);
}
else
{
break;
}
}
if (IsLoggedIn2() == false)
{
Process.Start(appDataCitrix + "Outlook.exe");
for (int i = 0; i < 10; i++)
{
if (IsLoggedIn2() == false)
{
Thread.Sleep(1000);
}
else
{
break;
}
}
}
}
Does anyone have any idea what is going on here? It is driving me crazy!
Many thanks
Update
The RunWorkerCompleted Method:
As far as my understanding goes, this has no baring on when the process will finish.
public void backgroundReset_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (Session.IsLoggedIn())
{
btnFailFinish.Visible = true;
label10.Text = Session.serverName;
pageControl1.SelectedIndex = 3;
}
else
{
pageControl1.SelectedIndex = 10;
pictureBox2.Visible = false;
textBox1.Text = "Double-click Outlook on your desktop to launch a new session.";
textBox15.Text = "Once you have done this please click Finish.";
pictureBox9.Visible = true;
}
}
This is probably because of an exception being thrown from within the start method.
You may either add a try / catch block all around this method and handle the error from within the catch, or check in the RunWorkerCompleted method if an exception occurred :
private void RunWorkerCompleted (object sender, RunWorkerCompletedEventArgs e)
{
if (e.Error != null)
{
// handle your exception here
}
}
I'm writing a program, that should replace or remove some entries from a logfile.txt.
The code is working fine ( at least for small LogFiles). If i use a big file (like 27 MB) its getting very slow and the UI freeze. I cant click anything.
On Button click i execute this method:
private string delete_Lines(string[] lines, string searchString)
{
for (int i = 0; i < lines.Length; i++)
{
if (lines[i].Contains(searchString))
{
rtbLog.Text += "Deleting(row " + (i + 1) + "):\n" + lines[i] + "\n";
progressBar1.Value += 1;
if (cbDB == true)
{
while (is_next_line_block(lines, i) == true)
{
i++;
rtbLog.Text += lines[i] + "\n";
progressBar1.Value += 1;
}
}
}
else
{
res += lines[i]+"\n";
progressBar1.Value += 1;
}
}
tssLbl.Text = "Done!";
rtbLog.Text += "...Deleting finished\n";
return res;
}
Lines is the array of the logfile i am trying to clean up. every entry is a single row . tssLbl is a notification label and rtbLog is a richTextBox, where i'am tracking which row i am deleting.
is_next_line_block is just another method, which is checking of the next lines are part of the block i want to delete. The params of this method are the whole lines array and the line position.
private bool is_next_line_block(string[] lines, int curIndex)
{
if (curIndex < lines.Length-1)
{
if (lines[curIndex + 1].StartsWith(" "))
{
return true;
}
else
{
return false;
}
}
else
{
return false;
}
}
Have anybody any idea, what is causing that freezes and is slowing down the program? I know, that i could speed my code up by parallelizing it, but i cant imagine, that it takes so long to check up a 27 MB txt file without parallelism.
You have several issues here:
You are reading the whole file in buffer (array of string), I am guessing you are calling File.ReadAllLines(). Reading big files in buffer will slow you down, as well as in extreme case run you out of memory.
You are using += operation for your rich textbox Text property. That is time consuming operation as UI has to render the whole rich text box every time you update the text property that way. Better option is to use string builder to load these text, and update rich text box periodically.
To fix this you need to read the file as stream. Progress can be monitored based on bytes read instead of line position. You can run the read operation async and monitor progression on a timer, as shown in example below.
private void RunFileOperation(string inputFile, string search)
{
Timer t = new Timer();
int progress = 0;
StringBuilder sb = new StringBuilder();
// Filesize serves as max value to check progress
progressBar1.Maximum = (int)(new FileInfo(inputFile).Length);
t.Tick += (s, e) =>
{
rtbLog.Text = sb.ToString();
progressBar1.Value = progress;
if (progress == progressBar1.Maximum)
{
t.Enabled = false;
tssLbl.Text = "done";
}
};
//update every 0.5 second
t.Interval = 500;
t.Enabled = true;
// Start async file read operation
System.Threading.Tasks.Task.Factory.StartNew(() => delete_Lines(inputFile, search, ref progress, ref sb));
}
private void delete_Lines(string fileName, string searchString, ref int progress, ref StringBuilder sb)
{
using (var file = File.OpenText(fileName))
{
int i = 0;
while (!file.EndOfStream)
{
var line = file.ReadLine();
progress = (int)file.BaseStream.Position;
if (line.Contains(searchString))
{
sb.AppendFormat("Deleting(row {0}):\n{1}", (i + 1), line);
// Change this algorithm for nextline check
// Do this when it is next line, i.e. in this line.
// "If" check above can check if (line.startswith(" "))...
// instead of having to do it nextline next here.
/*if (cbDB == true)
{
while (is_next_line_block(lines, i) == true)
{
i++;
rtbLog.Text += lines[i] + "\n";
progressBar1.Value += 1;
}
}*/
}
}
}
sb.AppendLine("...Deleting finished\n");
}
As a follow up to your question on Task.Factory.Start() usage, it's done this way (generally):
// you might need to wrap this in a Dispatcher.BeginInvoke (see below)
// if you are not calling from the main UI thread
CallSomeMethodToSetVisualCuesIfYouHaveOne();
Task.Factory.StartNew(() =>
{
// code in this block will run in a background thread...
}
.ContinueWith(task =>
{
// if you called the task from the UI thread, you're probably
// ok if you decide not to wrap the optional method call below
// in a dispatcher begininvoke...
Application.Current.Dispatcher.BeginInvoke(new Action(()=>
{
CallSomeMethodToUnsetYourVisualCuesIfYouHaveAnyLOL();
}));
}
Hope this helps!
Thanks to everybody for the help, especially loopedcode, That's the working version (Took loopedcode's code and made some edit):
private void RunFileOperation(string inputFile, string search)
{
Timer t = new Timer();
StringBuilder sb = new StringBuilder();
{
rtbLog.Text = "Start Deleting...\n";
}
// Filesize serves as max value to check progress
progressBar1.Maximum = (int)(new FileInfo(inputFile).Length);
t.Tick += (s, e) =>
{
rtbLog.Text += sb.ToString();
progressBar1.Value = progress;
if (progress == progressBar1.Maximum)
{
t.Enabled = false;
tssLbl.Text = "done";
}
};
//update every 0.5 second
t.Interval = 500;
t.Enabled = true;
// Start async file read operation
if (rbtnDelete.Checked)
{
if (cbDelete.Checked)
{
System.Threading.Tasks.Task.Factory.StartNew(() => delete_Lines(inputFile, search, ref progress, ref sb, ref res1));
}
}
else
{
//..do something
}
private void delete_Lines(string fileName, string searchString, ref int progress, ref StringBuilder sb, ref StringBuilder res1)
{
bool checkNextLine=false;
using (var file = File.OpenText(fileName))
{
int i = 0;
while (!file.EndOfStream)
{
i++;
var line = file.ReadLine();
progress = (int)file.BaseStream.Position;
if (line.Contains(searchString))
{
sb.AppendFormat("Deleting(row {0}):\n{1}\n", (i), line);
checkNextLine = true;
}
else
{
if (cbDB && checkNextLine && line.StartsWith(" "))
{
sb.AppendFormat("{0}\n", line);
}
else
{
checkNextLine = false;
res1.AppendLine(line);
}
}
}
}
sb.AppendLine("\n...Deleting finished!);
}
Is there any way i can display a String character by character? like in old RPGs
I've tried this:
string text1 ="this is a text";
for (int i = 0; i < text1.Length; i++)
{
textBox1.Text = "" + text1[i];
}
but it only replaces the last character on the text box.
Try This:
public partial class Form1 : Form
{
int count = 0;
string text1 = "this is a scrolling text";
System.Windows.Forms.Timer timer1 = new System.Windows.Forms.Timer();
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
button1.Enabled = false;
textBox1.ReadOnly = true;
SetTimer(500);
}
private void SetTimer(int milliseconds)
{
timer1.Tick+=new EventHandler(timer1_Tick);
timer1.Interval = milliseconds;
timer1.Start();
}
private void timer1_Tick(Object o, EventArgs e)
{
if (count < text1.Length)
{
textBox1.Text += text1[count];
count++;
}
else
{
timer1.Stop();
button1.Enabled = true;
textBox1.ReadOnly = false;
}
}
}
Output:
The following code should do it:
public Form1()
{
InitializeComponent();
TypeText("this is a text");
}
private void TypeText(string text)
{
textBox1.Clear(); // Make sure the textbox is empty
Thread thread = new Thread(delegate() // Create a new thread which fills the textbox periodically
{
button1.BeginInvoke((MethodInvoker)delegate { button1.Enabled = false; }); // Disables the button
for (int i = 0; i < text.Length; i++)
{
int temp = i; // Cache variable because without this, an 'ArgumentOutOfRange' Exception will be thrown
textBox1.BeginInvoke((MethodInvoker)delegate // Invoke to main thread
{
textBox1.Text += text[temp]; // Fill with next char
});
if (text[temp] != ' ') // This makes sure the user doesn't have to wait the double of the time when there is an empty space for the new character
Thread.Sleep(500); // This will stop the seperate thread for 500ms. Won't block the main thread
}
button1.BeginInvoke((MethodInvoker)delegate { button1.Enabled = true; }); // Reenables the button
});
thread.Start(); // Start the new thread and continue the main thread
}
I'm not sure exactly how that helps you. You might want to add why you are doing this. The issue you are having with your code is that your are not appending to the string. Try this line instead:
textBox1.Text += text1[i];
You need to clear textBox1.Text before you start (set it to "").
A better approach might be to print out the hex values so that non printing characters are easily seen. You can do something like this:
string text1 ="this is a text";
var sb = new StringBuilder();
for (int i = 0; i < text1.Length; i++) {
sb.AppendFormat("{0:X} ", text1[i]);
}
textBox1.Text = sb.ToString();
Reading Jeroen Vannevel makes me thing that you are trying to create a "typewriter" affect. In that case try something like:
string text1 ="this is a text";
textBox1.Text = "";
for (int i = 0; i < text1.Length; i++) {
textBox1.Text += text1[i];
Thread.Sleep(250); // 1/4 sec delay
}
This code was written modeled on the code given. There is an implied expectation that this is run from the main UI thread. This means that when you are sitting in a loop with a Sleep delay your UI will be unresponsive (since you are tying up the main thread). You can overcome this by using the Invoke method on the Dispatcher object (of your App) and running the code on a different thread. You should only Invoke the parts that are owned by the main UI (textBox1) in this case.
textBox1.Text = textBox1.Text + text1[i]
To me it seems that you want to break a string into its characters, there are several ways to do that:
1 - String.GetChar() Method:
http://msdn.microsoft.com/en-us/library/microsoft.visualbasic.strings.getchar%28v=vs.110%29.aspx
2 - String.Chars property:
http://msdn.microsoft.com/en-us/library/system.string.chars%28v=vs.110%29.aspx
TextBox1.Text += MyString.Chars[i];
Then if you want to show them one by one with a delay or something like that, you can use timers as others have suggested.
Here I am working on creating a simple practice windows phone app that simulates a guessing game. I have a while loop that runs the game until the user guesses the correct answer; what I want to do is at the beginning of each loop, wait for the user to trigger an event from pressing enter in the textbox. I'm new to this idea and have no experience in multi-threading.
I am getting an unauthorizedaccessexception, and I'm not sure what is causing it.
public partial class MainPage : PhoneApplicationPage
{
Random r;
int guess;
static AutoResetEvent autoEvent;
// Constructor
public MainPage()
{
InitializeComponent();
r = new Random();
autoEvent = new AutoResetEvent(false);
Thread t = new Thread(PlayGuessGame);
t.Start();
}
private void PlayGuessGame()
{
bool hasWon = false;
int secretNumber = r.Next(1, 3);
int tries = 1;
messageTextBox.Text = "Guess a number";
while (!hasWon)
{
autoEvent.WaitOne();
if (guess == secretNumber) //if user wins
{
messageTextBox.Text = "Congratulations! You've guess the correct number! It took {0} tries.";
}
else
{
tries++;
if (guess < secretNumber)
messageTextBox.Text = "Guess higher!";
else
messageTextBox.Text = "Guess lower!";
lastGuessTextBox.Text = guess.ToString();
}
}
}
private void guessTextBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
guess = int.Parse(guessTextBox.Text);
autoEvent.Set();
}
}
}
The issue you're experiencing is because you are trying to access an object from a thread it wasn't created by. So the thread that is running your PlayGuessGame() isn't supposed to play in that sandbox. You can get around this though by using a MethodInvoder:
private void PlayGuessGame()
{
bool hasWon = false;
int secretNumber = r.Next(1, 3);
int tries = 1;
messageTextBox.Text = "Guess a number";
while (!hasWon)
{
autoEvent.WaitOne();
if (guess == secretNumber) //if user wins
{
this.Invoke(new MethodInvoker(delegate { messageTextBox.Text = "Congratulations! You've guess the correct number! It took {0} tries."; }));
}
else
{
tries++;
if (guess < secretNumber)
this.Invoke(new MethodInvoker(delegate { messageTextBox.Text = "Guess higher!"; }));
else
this.Invoke(new MethodInvoker(delegate { messageTextBox.Text = "Guess lower!"; }));
this.Invoke(new MethodInvoker(delegate { lastGuessTextBox.Text = guess.ToString(); }));
}
}
}
I would definitely recommend Brian Warshaw's comment, this should be an event driven GUI. Hope this helped though, you could use this elsewhere you are using threads!