Develop Reference

c# charting - access from other thread exception

Today I was trying to chart data from project where I recieve it by transmitting from my uC via UART.
The program is just to recieve data in interrupt, process it and display.
When program goes to my ChartData method I'm getting an exception:
An unhandled exception of type 'System.InvalidOperationException'
occurred in System.Windows.Forms.dll
Additional information: Cross-thread operation not valid: Control
'chart1' accessed from a thread other than the thread it was created
on.
It is strange for me - I think that I've got one thread in my program.
I have tried charting with pure project where I create data in Form_Load event - everything works fine.
My source code is here - any idea?
public partial class Form1 : Form
{
private List<float> freqList = new List<float>();
private List<float> magList = new List<float>();
private float[] fFrequency = new float[numberOfSamples];
private float[] fMagnitude = new float[numberOfSamples];
public static int counterOfRecBytes = 0;
public static int numberOfSamples = 512;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
GetAvailablePorts();
tb_Rx.Text = "Wprowadź parametry transmisji";
// Default transmission parameters for testing
cb_BaudRate.Text = "9600";
cb_Ports.Text = "COM5";
}
/// <summary>
/// Checks avaiable serialports - for linking my device to other computers
/// </summary>
void GetAvailablePorts()
{
string[] ports = SerialPort.GetPortNames();
cb_Ports.Items.AddRange(ports);
//cb_Ports.SelectedIndex = 0;
}
private void bt_connect_Click(object sender, EventArgs e)
{
if (bt_connect.Text == "Connect")
{
if (cb_Ports.Text == "" || cb_BaudRate.Text == "" || cb_Ports.Text == "")
tb_Rx.Text = "Nie wybrano jednego z parametrów";
else
{
bt_connect.Text = "Disconnect";
SerialP.PortName = cb_Ports.Text;
SerialP.BaudRate = Convert.ToInt32(cb_BaudRate.Text);
SerialP.StopBits = StopBits.One;
SerialP.DataBits = 8;
SerialP.Parity = Parity.None;
SerialP.Handshake = Handshake.None;
SerialP.ReadBufferSize = 8 * numberOfSamples + 4;
SerialP.Open();
pb_connect.Value = 100;
tb_Rx.Clear();
cb_Ports.Enabled = false;
cb_BaudRate.Enabled = false;
}
}
else
{
SerialP.Close();
bt_connect.Text = "Connect";
pb_connect.Value = 0;
bt_connect.Enabled = true;
cb_BaudRate.Enabled = true;
cb_Ports.Enabled = true;
freqList.Clear();
magList.Clear();
pb_connect.Value = 0;
tb_Rx.AppendText(Environment.NewLine + "----Zamknięto połączenie----");
}
}
private void SerialP_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
byte[] bArray = new byte[8 * numberOfSamples+4]; // frequencies (512 samples) and magnitudes (512 values) - each is a single precision float so 4 bytes
float[] fArray = new float[2*numberOfSamples];
//bool dataStart = false;
int previouse = counterOfRecBytes;
counterOfRecBytes += sp.BytesToRead;
sp.Read(bArray, previouse, (counterOfRecBytes - previouse));
if (counterOfRecBytes == 8*numberOfSamples+4)
{
for(uint i = 1; i < 2*numberOfSamples+1; i++)
{
// if (freqList.Count == numberOfSamples) freqList.Clear();
// if (magList.Count == numberOfSamples) magList.Clear();
fArray[i-1] = ByteToFloat(bArray, i);
if (i < numberOfSamples+1) freqList.Add(fArray[i]);
else magList.Add(fArray[i-1]);
}
//ListToArray();
ChartData();
// if (counterOfRecBytes >= 8 * numberOfSamples + 4) sp.DiscardInBuffer();
counterOfRecBytes = 0;
}
}
/// <summary>
/// Changes my recieved bArray to single precision floats
/// </summary>
private float ByteToFloat(byte[] input, UInt32 i)
{
byte[] array = new[] { input[4 * i], input[4 * i + 1], input[4 * i + 2], input[4 * i + 3] };
return BitConverter.ToSingle(array, 0);
}
/// <summary>
/// Setting chart data
/// </summary>
private void ChartData()
{
for (int i = 0; i < numberOfSamples; i++)
{
chart1.Series["Widmo"].Points.AddXY(freqList[i], magList[i]);
}
}
}
Problem solved - what I had to do was putting code below in place of just calling ChartData method:
if (InvokeRequired)
{
Invoke(new MethodInvoker(ChartData));
}
else
{
ChartData();
}

Noise artifacts during Naudio stream

I'm having some outputting my data as audio stream.
I've uploaded a sound snipped of a sine wave with the undesirable noise effect.
I think the issue is related that there is a small pause between data packages and somehow this produces this low, fairly regular pop sound
The AudioMonitor class gets its data via SetBuffer, each 250ms aprrox. ~ 6000 samples.
Where does the noise originate from exactly ?
What can be done to fix this ?
Edit *Seems to be an issue that the data isn't seamlessly coming in. After one package was played, there is a pause, the waveprovider idling and the clicking noise occurs.
Isn't it possible to just get a silence for the time there is no sample ready?*
Audacity view of the signal
using System;
using NAudio.Wave; // Version 1.7.0.13
namespace aws
{
public class AudioMonitor
{
private BufferedWaveProvider waveProvider;
private WaveOut wavePlayer;
int audioFilter = 0;
int sampleRate = 31250;
int resolution = 8;
private void CreateAudio()
{
if (wavePlayer != null)
{
StopAudio();
wavePlayer.Dispose();
wavePlayer = null;
waveProvider = null;
}
waveProvider = new BufferedWaveProvider(new WaveFormat(sampleRate, resolution, 1));
waveProvider.BufferLength = 31250; // standard value: 31250
wavePlayer = new WaveOut();
wavePlayer.DesiredLatency = 300; // standard value: 300
wavePlayer.NumberOfBuffers = 2; // standard value: 2
wavePlayer.Init(waveProvider);
}
public bool StartAudio()
{
CreateAudio();
if (wavePlayer != null)
{
wavePlayer.Play();
return true;
}
return false;
}
public void StopAudio()
{
if (wavePlayer != null)
{
wavePlayer.Stop();
}
}
public PlaybackState GetPlaybackState()
{
if (wavePlayer != null)
{
return wavePlayer.PlaybackState;
}
return PlaybackState.Stopped;
}
public void SetBuffer(byte[] b)
{
int indexWrite = 0, indexBuffer = 0, sizeBuffer;
byte[] nbuffer = b;
sizeBuffer = b.Length;
// valid data
for (indexWrite = indexBuffer; indexWrite < (indexBuffer + sizeBuffer); ++indexWrite)
{
nbuffer[indexWrite] = (Byte)((nbuffer[indexWrite]) + 128);
if ((nbuffer[indexWrite] < (128 + audioFilter)) && (nbuffer[indexWrite] > (128 - audioFilter)))
nbuffer[indexWrite] = 128;
}
try
{
waveProvider.AddSamples(nbuffer, indexBuffer, sizeBuffer);
}
catch (Exception e){
Console.WriteLine(e.StackTrace);
}
}
public void SetBuffer(double[] d, double fac)
{
byte[] tmpBuf = new byte[d.Length];
for(int i = 0; i < tmpBuf.Length; i++)
{
tmpBuf[i] = (byte)(d[i] / fac);
}
SetBuffer(tmpBuf);
}
public void SetAudioFilter(int f)
{
audioFilter = f*3; // min 0 max 60
}
public void Finalize()
{
if (wavePlayer != null)
{
wavePlayer.Stop();
wavePlayer.Dispose();
}
}
}
}

Ping Completed Event Handler not working [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 7 years ago.
Improve this question
When I execute this code in command line, it's working fine:
class Program
{
private static List<Ping> pingers = new List<Ping>();
private static List<string> value = new List<string>();
private static int instances = 0;
private static object #lock = new object();
private static int result = 0;
private static int timeOut = 2500;
private static int ttl = 7;
public static void Main()
{
string baseIP = "192.168.1.";
Console.WriteLine("Pinging destinations of D-class in {0}*", baseIP);
CreatePingers(254);
PingOptions po = new PingOptions(ttl, true);
System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
byte[] data = enc.GetBytes("");
SpinWait wait = new SpinWait();
int cnt =1;
Stopwatch watch = Stopwatch.StartNew();
foreach (Ping p in pingers)
{
lock (#lock)
{
instances += 1;
}
p.SendAsync(string.Concat(baseIP, cnt.ToString()), timeOut, data, po);
cnt += 1;
}
//while (instances > 0)
//{
// wait.SpinOnce();
//}
watch.Stop();
for (int i = 0; i < value.Count; i++)
{
Console.WriteLine(value[i]);
}
DestroyPingers();
Console.WriteLine("Finished in {0}. Found {1} active IP-addresses.", watch.Elapsed.ToString(), result);
Console.ReadKey();
}
public static void Ping_completed(object s, PingCompletedEventArgs e)
{
lock (#lock)
{
instances -= 1;
}
if (e.Reply.Status == IPStatus.Success)
{
string sa = string.Concat("Active IP: ", e.Reply.Address.ToString());
value.Add(sa);
//Console.WriteLine(sa);
String diachiip = e.Reply.Address.ToString();
result += 1;
}
else
{
//Console.WriteLine(String.Concat("Non-active IP: ", e.Reply.Address.ToString()))
}
}
private static void CreatePingers(int cnt)
{
for (int i = 1; i <= cnt; i++)
{
Ping p = new Ping();
p.PingCompleted += Ping_completed;
pingers.Add(p);
}
}
private static void DestroyPingers()
{
foreach (Ping p in pingers)
{
p.PingCompleted -= Ping_completed;
p.Dispose();
}
pingers.Clear();
}
}
But when I convert from it to window form, it doesn't work. I don't kwow why, I have tried many different ways...
Code is here:
public partial class Form1 : Form
{
public static List<Ping> pingers = new List<Ping>();
public static List<string> value = new List<string>();
public static int instances = 0;
public static object #lock = new object();
public static int result = 0;
public int timeout = 2500;
public static int ttl = 7;
public Form1()
{
InitializeComponent();
}
public void btnscan_Click(object sender, EventArgs e)
{
string baseIP = "192.168.1.";
//int kt = Int32.Parse(txtkt.Text);
//int start = Int32.Parse(txtstart.Text);
CreatePingers(254);
PingOptions po = new PingOptions(ttl, true);
System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
byte[] data = enc.GetBytes("");
int cnt = 1;
Stopwatch watch = Stopwatch.StartNew();
foreach (Ping p in pingers)
{
lock (#lock)
{
instances += 1;
}
p.SendAsync(string.Concat(baseIP, cnt.ToString()), timeout, data, po);
cnt += 1;
}
watch.Stop();
//Result alway return 0
lst1.Items.Add(result.ToString());
lst1.Items.Add(value.Count.ToString());
for (int i = 0; i < value.Count; i++)
{
lst1.Items.Add(value[i]);
lst1.Items.Add("\n");
}
DestroyPingers();
string a = "Finished in " + watch.Elapsed.ToString() + ". Found " + result + " active IP-addresses.";
lst1.Items.Add(a);
}
public static void CreatePingers(int kt)
{
for (int start = 1; start <= kt; start++)
{
// class System.Net.NetworkInformation.Ping
Ping p = new Ping();
p.PingCompleted += Ping_completed();
pingers.Add(p);
}
}
public static PingCompletedEventHandler Ping_completed()
{
PingCompletedEventHandler a = new PingCompletedEventHandler(abc);
return a;
}
static void abc(object s, PingCompletedEventArgs e)
{
value.Add("abc");
lock (#lock)
{
instances -= 1;
}
if (e.Reply.Status == IPStatus.Success)
{
string abcd = string.Concat("Active IP: ", e.Reply.Address.ToString());
value.Add(abcd);
result += 1;
}
}
public static void DestroyPingers()
{
foreach (Ping p in pingers)
{
p.PingCompleted -= Ping_completed();
p.Dispose();
}
pingers.Clear();
}
}
What is wrong in this code?

Method SendAsync returns 0 because you are not waiting for it to complete. You are missing await and async (see msdn):
async void btnscan_Click(object sender, EventArgs e)
{
...
await p.SendAsync(string.Concat(baseIP, cnt.ToString()), timeout, data,
...
}
SpinWait was making code to work in console application. In winforms you should not use SpinWait (nor Sleep) in UI thread. You can create another thread (e.g. by using Task) and then you can copy/paste code from console application 1-to-1. But then you will need to use Invoke each time when you want to access UI controls.
async/await is really better.. if it will work (I concluded that from method name, I've no idea what method does, nor how to use it).
Perhaps I miss one thing, if SendAsync returns value, then you can get it by (the requirement to mark method where you use await with async still):
var result = await p.SendAsync(...);

Trying to loop HttpWebRequest with no success

I am trying to create a program which can sort the number of results associated with any specified google search. I need a big table very fast so I thought about using a loop. Each time I try it though, the debugger crashes due to a "System.Windows.Markup.XamlParseException".
public long resultStat(string a)
{
var req = (HttpWebRequest)WebRequest.Create("https://www.google.ca/search?hl=fr&output=search&sclient=psy-ab&q=a" + a + "&btnK=");
using (req as IDisposable)
{
WebResponse rep = req.GetResponse();
Stream str = rep.GetResponseStream();
StreamReader rdr = new StreamReader(str);
string res = rdr.ReadToEnd();
rdr.Close();
//This is my code to get the number results (it works perfectly)
int index = res.IndexOf(">Environ");
int cond = 0;
string final = "";
try
{
while (res[++index] != '<')
{
if (cond-- == 0 && res[index] != '&')
{ final += res[index]; cond = 0; }
else if (res[index] == '&') cond = 5;
}
}
catch { return 0; }
string temp = "";
foreach (char i in final) if (i < 48 && i > 58) temp += i;
return Int64.Parse(temp);
}
}
This whole method is simply used in the main in a for loop such as :
public void main()
{
//Other code
for (int i = 0; i < 3; i++) resultStat(i.ToString()); // For example
//Other code
}
I know it's the problem because as soon as I comment the loop, or lower it to one rep, nothing goes wrong. I've tried:
HttpWebRequest().Abort();
HttpWebRequest().KeepAlive = false;
It didn't work

I don't think the away you are doing is the correct way to do this. The simple one i can tell you is use Lib curl c#. You can send in an array of urls and get response as an array. That would be perfect for what you require here. Here is a sample class code below that does the multitasking itself. You just send in the urls.
public class MultiHttp
{
public static string UserAgent = "Mozilla 5.0";
public static string Header = "Content-Type: application/x-www-form-urlencoded; charset=UTF-8";
private static string[] Result;
public static string[] MultiPost(string[] Url, string post, int timeOut)
{
Result = new string[post.Length];
try
{
Curl.GlobalInit((int)CURLinitFlag.CURL_GLOBAL_ALL);
Easy.WriteFunction wf = new Easy.WriteFunction(OnWriteData);
//Easy.HeaderFunction hf = new Easy.HeaderFunction(OnHeaderData);
Easy[] easy = new Easy[Url.Length];
Multi multi = new Multi();
for (int i = 0; i < Url.Length; i++)
{
if (Url[i] != null)
{
easy[i] = new Easy();
easy[i].SetOpt(CURLoption.CURLOPT_URL, Url[i]);
easy[i].SetOpt(CURLoption.CURLOPT_WRITEFUNCTION, wf);
easy[i].SetOpt(CURLoption.CURLOPT_WRITEDATA, i);
//easy[i].SetOpt(CURLoption.CURLOPT_HEADERFUNCTION, hf);
//easy[i].SetOpt(CURLoption.CURLOPT_HEADERDATA, i);
easy[i].SetOpt(CURLoption.CURLOPT_TIMEOUT, timeOut);
easy[i].SetOpt(CURLoption.CURLOPT_USERAGENT, UserAgent);
Slist sl = new Slist();
sl.Append(Header);
easy[i].SetOpt(CURLoption.CURLOPT_HTTPHEADER, sl);
easy[i].SetOpt(CURLoption.CURLOPT_POSTFIELDS, post);
easy[i].SetOpt(CURLoption.CURLOPT_FOLLOWLOCATION, true);
easy[i].SetOpt(CURLoption.CURLOPT_POST, true);
//easy[i].SetOpt(CURLoption.CURLOPT_NOBODY, true);
if (Url[i].Contains("https"))
{
easy[i].SetOpt(CURLoption.CURLOPT_SSL_VERIFYHOST, 1);
easy[i].SetOpt(CURLoption.CURLOPT_SSL_VERIFYPEER, 0);
}
multi.AddHandle(easy[i]);
}
}
int stillRunning = 1;
while (multi.Perform(ref stillRunning) == CURLMcode.CURLM_CALL_MULTI_PERFORM) ;
while (stillRunning != 0)
{
multi.FDSet();
int rc = multi.Select(1000); // one second
switch (rc)
{
case -1:
stillRunning = 0;
break;
case 0:
default:
{
while (multi.Perform(ref stillRunning) == CURLMcode.CURLM_CALL_MULTI_PERFORM) ;
break;
}
}
}
// various cleanups
multi.Cleanup();
for (int i = 0; i < easy.Length; i++)
{
easy[i].Cleanup();
}
Curl.GlobalCleanup();
}
catch (Exception)
{
//r = ex+"";
}
return Result;
}
public static Int32 OnWriteData(Byte[] buf, Int32 size, Int32 nmemb,
Object extraData)
{
int tmp = Convert.ToInt32(extraData.ToString()); ;
Result[tmp] += System.Text.Encoding.UTF8.GetString(buf);
return size * nmemb;
}
}
Call it like :
String[] url= new String[2];
url[1]="https://www.google.ca/search?hl=fr&output=search&sclient=psy-ab&q=a1&btnK=";
url[2]="https://www.google.ca/search?hl=fr&output=search&sclient=psy-ab&q=a2&btnK=";
string postString=""; // IF YOU DO NOT WANT TO POST ANYTHING YOU CAN DO THE SAME THING KEEP URL THE SAME SEND POST ARRAY AND CHANGE THE CLASS IT WORKS BOTH WAYS
String[] result = MultiHttp.MultiPost(url, postString, timeOut);
Its just a sample but will get you the working idea to sort out your problem.

c# text difference

I have two words:
Source: John
ConvertTo: Jack
and I want to show the effect of convert all letters from "Source" at the same time to the "ConvertTo" word. I already create a program to accomplish that but processing one letter at a time, to show the effect I use Threads, the thing is that to process all letters at the same time I suppose I need one thread per letter, and every thread will call the same function that process the letter, and I use global variables.
Here is the code (works only for texts with same lenght):
private void button1_Click(object sender, EventArgs e)
{
lblResult.Text = "";
lblResult2.Text = "";
ThreadPool.QueueUserWorkItem(new WaitCallback(Process));
}
int movement = 0;
string CumulateText;
private void Process(object stateinfo)
{
int value;
int operation; //0->[+] 1->[-]
CumulateText = "";
for (int i = 0; i <= textBox1.Text.Length - 1; i++)
{
if (textBox1.Text[i] != ' ')
{
value = (char)textBox1.Text[i] - (char)textBox2.Text[i];
if (value >= 0)
operation = 1;
else
operation = 0;
for (int ii = 0; ii <= Math.Abs(value); ii++)
{
if (operation == 1)
movement = (char)textBox1.Text[i] - ii;
else
movement = (char)textBox1.Text[i] + ii;
this.Invoke(new EventHandler(ShowMovement));
System.Threading.Thread.Sleep(10);
}
}
CumulateText += textBox2.Text[i].ToString();
}
}
private void ShowMovement(object sender, EventArgs e)
{
lblResult.Text = CumulateText + Convert.ToString((char)movement);
}
I hope I made myself understood.
please any advise to accomplish that.
thanks
To clarify more what I want to accomplish here is an example:
Source: John
ConvertTo: Jack
J - same J
o - decrease till a (o, n, m, ..., a)
h - decrease till c (h, g, f, ..., c)
n - decrease till k (n, m, l, k)

I once had to do something similar for a small little project I was working on for fun.
I do not see why you would need to create a thread for each letter to create a transition between two words unless I'm not understanding what you are pretending to do correctly.
Check and study the following code, see if its any help:
static class Program
{
static void Main()
{
TextTranstition transition = new TextTranstition();
transition.TransitionFinished += TransitionTicked;
transition.TransitionTicked += TransitionTicked;
transition.StartTransition("AmazingWordTransition", "MyNewWordAppearing", 100);
Thread.CurrentThread.Join();
Console.ReadKey();
}
public static void TransitionTicked(object sender, TranstitionEventArgs e)
{
Console.Clear();
Console.Write(e.TransitionText);
}
}
public class TranstitionEventArgs : EventArgs
{
private readonly string transitionText;
public string TransitionText { get { return this.transitionText; } }
public TranstitionEventArgs(string transitionText)
{
this.transitionText = transitionText;
}
}
public class TextTranstition
{
private struct StartInfo
{
public StartInfo(string initialText, string finalText, int timeStep)
{
this.initialText = initialText;
this.finalText = finalText;
this.timeStep = timeStep;
}
private readonly string initialText;
public string InitialText { get { return this.initialText; } }
private readonly string finalText;
public string FinalText { get { return this.finalText; } }
private readonly int timeStep;
public int TimeStep { get { return this.timeStep; } }
}
public EventHandler<TranstitionEventArgs> TransitionFinished;
public EventHandler<TranstitionEventArgs> TransitionTicked;
public void StartTransition(string initialText, string finalText, int timeStep)
{
StartInfo startInfo = new StartInfo(initialText, finalText, timeStep);
Thread t = new Thread(startTransition);
t.Start(startInfo);
}
private void startTransition(object info)
{
StartInfo startInfo = (StartInfo)info;
string initialText = startInfo.InitialText;
string finalText = startInfo.FinalText;
if (initialText.Length < finalText.Length)
{
initialText = initialText.PadRight(finalText.Length);
}
if (TransitionTicked != null) TransitionTicked(this, new TranstitionEventArgs(initialText));
while ((initialText = transition(initialText, finalText)) != finalText)
{
Thread.Sleep(startInfo.TimeStep);
if (TransitionTicked != null) TransitionTicked(this, new TranstitionEventArgs(initialText));
}
if (TransitionFinished != null) TransitionFinished(this, new TranstitionEventArgs(finalText));
}
private string transition(string initialText, string finalText)
{
StringBuilder b = new StringBuilder(finalText.Length);
for (int i = 0; i < finalText.Length; i++)
{
char c = initialText[i];
int charCode = (int)c;
if (c != finalText[i])
{
if (charCode == 122 || charCode==32) charCode = 65;
else if (charCode == 90) charCode = 97;
else
{
charCode += 1;
}
}
b.Append((char)charCode);
}
return b.ToString();
}
}

Use BackgroudWorker for this kind of stuff.