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Here is the code, I have tested the snmpconn method in a commandline application it works but it freezes during runtime in windows form application, I have no reason why ?
public snmpmain()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
this.button1.Click += new System.EventHandler(this.snmpconn);
}
private void button1_Click(object sender, EventArgs e)
{
//button1.Enabled = false; will disable the button before the event is fired
this.button1.Click += new System.EventHandler(this.snmpconn);
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}
int port = 162;
// UdpClient listener;
// IPEndPoint groupEP;
byte[] packet = new byte[1024];
int commlength, miblength, datatype, datalength, datastart, Objecttype, Objectlength;
int agent;
int timestamp;
int entrspc;
int specifictrap;
int finallen;
int objectstart;
string objectid;
string test1;
byte[] test2 = new byte[1024];
int temp;
string tempo;
private void snmpconn(object sender, System.EventArgs e)
{
listBox1.Items.Add("Initializing" + port + "...");
this.button1.Click -= new System.EventHandler(this.snmpconn);
UdpClient listener = new UdpClient(port);
IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, port);
while (true)
{
listBox1.Items.Add("Waiting....");
packet = listener.Receive(ref groupEP);
listBox1.Items.Add("Processing...");
if (packet.Length != 0)
{ // do some work
}
}
}
This works well with command line application.
Do you have a clue .
Woah, i answered without noticing the main mistake!!
while (true)
Please, don't do it, almost never, if you're not sure of what you're doing!!
You're allocating 100% resources of your process while standing in that loop, without ever leaving a single bit of CPU to perform rendering.
You should read & learn about multi-threading & synchronization before an attempt to make your code working fine.
Then, you're binding too much events to your btn click!
This row:
this.button1.Click += new System.EventHandler(this.snmpconn);
is not necessary on button1_Click event.
Also, playing with binding events on click may be misleading, you could use a flag (true/false) to check whether to perform your function when btn is clicked.
Related
i am getting data from serial port interface each data stream (packet) consist of 1kbytes. these values are basic digital oscilloscope analog signals. After processing these datas i draw the signals to the screen.
The problem is if i call the function which process the signals from serial port "DataReceivedHandler" it takes too much time(200mS) and too much process power. But when i call my function seperatly like via button click it took 10mS. After debugging too many times i couln't find why is this taking too long? what are the possible reasons for this? can you give me some solutions?
In two examples below results are correct but time consuming different.
public void DataReceivedHandler(
object sender,
SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
int temp_buffer_count;
temp_buffer_count = sp.BytesToRead;
label55.Text += temp_buffer_count.ToString() + "--";
serialPort1.Read(readBuffer, uart_count, temp_buffer_count);
uart_count += temp_buffer_count;
if(uart_count>3)
{
int dataadet = readBuffer[1] * 256 + readBuffer[2] + 3;
if(uart_count>= dataadet)
{
if(readBuffer[0]==0xff)
{
UdpReceivedData = new byte[dataadet + 100];
Array.Copy(readBuffer, ReceivedData, dataadet);
uart_count = 0;
dataadet = 0;
if(ReceivedData[3]==AdcDataIslemi)
{
stopwatch2.Resart();
//this function tooks too much time
PreparePage(false, true);
stopwatch2.Stop();
}
}
}
}
}
if i call same function with a button click that function is executing 20 times faster.
private void button2_Click(object sender, EventArgs e)
{
stopwatch2.Resart();
PreparePage(false, true);
stopwatch2.Stop();
}
I am new to C# and am looking for some advice on an issue I have been trying to solve in my Windows Form application.
I have an application that needs to continuously read data coming back to the program over a connected serial port. I have buttons that Open and Close the port via the user. I am having trouble configuring the "DataReceived" event handler to read the incoming data and display it in a textbox in the app.
I have been getting this error: "Cross-thread operation not valid: Control 'textBox4' accessed from a thread other than the thread it was created on." I see this is a thread error but I have not been able to figure out my issue.
namespace Program
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
getAvailabePorts();
}
private void getAvailabePorts()
{
String[] ports = SerialPort.GetPortNames();
comboBox1.Items.AddRange(ports);
}
public void button1_Click(object sender, EventArgs e)
{
try
{
if (comboBox1.Text == "" || comboBox2.Text == "")
{
textBox4.Text = "Please select port settings";
}
else
{
serialPort1.PortName = comboBox1.Text;
serialPort1.BaudRate = Convert.ToInt32(comboBox2.Text);
serialPort1.DataReceived += new SerialDataReceivedEventHandler(mySerialPort_DataReceived);
serialPort1.Open();
}
}
catch (UnauthorizedAccessException)
{
textBox4.Text = "Unauthorized Access";
}
public void mySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort)sender;
textBox4.Text = sp.ReadExisting() + "\n";
}
private void button2_Click(object sender, EventArgs e)
{
serialPort1.Close();
textBox4.Clear();
}
}
}
}
First, welcome.
Before the "big" issue (marshalling data), let me warn you -- serial ports are tricky. For example, your call to "ReadExisting" may not return what you expect -- will return whatever is in the serial port buffer at the time, but more may come in, which will overwrite what is already in your text box. So you may want to append data your text box.
Now the real issue. As a commentor mentioned, you cannot post directly post data from another thread to the UI thread. Without you knowing, the serial port created a new thread to receive data.
You can handle this directly by modifying your receiver code as follows:
public void mySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
SerialPort sp = (SerialPort) sender;
var dataRcvd = sp.ReadExisting();
object[] dataArray = new object[1];
dataArray[0] = dataRcvd;
BeginInvoke( new postDataDelegate( postData), dataArray );
}
private delegate void postDataDelegate( string d );
private void postData( string d)
{
textBox4.Text = d;
}
This will "marshall" the data to the UI thread so it can be used. There are many ways this can be done (and, many differences between how it is done in WPF vs. Winforms, so watch out for that). I hope this illustrates the point.
Another aside -- no need ot make the DataReceived method public -- it will work fine private.
I'm new to the Arduino and serial communication, and I haven't coded in a while, but I'm trying to do what I think should be fairly simple, and have been having plenty of trouble. What I'd like to do is to create a simple GUI on Windows Forms and control a Arduino. I keep seeming to run into different problems every new session.
What I've been trying to do is to create a simple GUI that can toggle an LED on and off, and then to use NumericUpDown to toggle it blinking. Previously, I could get the numericUpDown to toggle values but nothing happens, now if I try and toggle, it tells me the port is closed. I've been trying different port communication methods. Since the Form is saying my port is closed, I cannot test to see if what I've written works. Please ignore the commented code as I'm still trying different things.
When I try to call the blink function, it hasn't blinked properly inside a if statement compared to if I kept it in the loop. I'm not sure how and where to send the value from the Winform to the Arduino.
Is Winform much different than using serial monitor commands?
EDIT1: I stepped away from my computer and now when I run the Windows Form, it shows no errors but The program has exited with code 0 (0x0). I've had the timer and haven't really messed with it yet but it wasn't telling me this error earlier and was running the form fine.
My Arduino Code:
// Define Function Prototypes that use User Types below here or use a .h file
int dorun;
int Blinks;
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(9600);
getBlinks();
}
// the loop function runs over and over again forever
void loop()
{
if (Serial.available() > 0)
/*
{
byte Blinktimes = Serial.readBytes[];
}
*/
{
String serialInput = Serial.readString();
//Toggle LED
if (serialInput == "On")
{
digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN)); //I have this just to see that the LED is staying on and off, and will need to change things.
for (int x = 1; x = Blinks; x++)
{
blink();
}
}
else
{
digitalWrite(LED_BUILTIN, LOW); // turn the LED on (LOW is the voltage level)
}
Serial.flush(); //Clear Serial
}
/*
digitalWrite(LED_BUILTIN, HIGH);
if ((Serial.available()))
{
int dorun = Serial.read();
if (dorun = 1)
{
blink();
}
else
{
digitalWrite(LED_BUILTIN, LOW);
}
}
*/
/*turnon();
if (dorun == 1)
{
blink();
}
else
{
digitalWrite(LED_BUILTIN, LOW);
}
*/
}
void getBlinks()
{
byte message[3];
if (Serial.available())
{
Serial.readBytes(message, 3);
Blinks = message[3];
}
}
void blink()
{
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the
voltage level)
delay(250); // wait for a second
digitalWrite(LED_BUILTIN, LOW); //!digitalRead(LED_BUILTIN); // turn the LED off by making the voltage LOW
delay(1000);
}
void turnon()
{
if (Serial.available()> 0)
{
String run = Serial.readString();
if (run == "Run")
{
dorun == 1;
}
if (run == "Off")
{
dorun == 0;
}
}
}
My Windows Form Code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO.Ports;
namespace WindowsFormsApp9
{
public partial class Form1 : Form
{
SerialPort serial; // create serial port
/*
* public class Port
{
public string Name { get; set; }
public int Value { get; set; }
public Port(string n, int i)
{
Name = n;
Value = i;
}
}
*/
SerialPort port;
string[] availablePorts = SerialPort.GetPortNames();
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
port.Open();
port.Write("On");
port.Close();
}
private void button2_Click(object sender, EventArgs e)
{
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
port.Open();
port.Write("Off");
port.Close();
}
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
UpdateBlink();
}
void UpdateBlink()
{
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
port.Open();
const byte messageType = 2;
byte Blinkcount = (byte)numericUpDown1.Value;
byte[] serialBlink = { messageType, Blinkcount };
serialPort1.Write(serialBlink, 0, serialBlink.Length);
port.Close();
}
private void timer1_Tick(object sender, EventArgs e)
{
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
}
I've been checking out these links:
Click here How I toggle the LED
Click here How to return an int since NumericUpDown returns a decimal
Click [here] (https://www.instructables.com/id/Arduino-Visual-Studio-Serial-Communication/) Arduino Visual Studio Serial communication timer things
Click [here] (https://www.instructables.com/id/Communication-From-a-WinForms-to-a-TinyDuino/) instructions about Winforms to TinyDuino, They should use similar commands as the Arduino right?
So I decided to do a slight overhaul. Instead of trying to deal with sending multiple different types of inputs(String and int) I have decided to just change everything into a byte array and then send it all at once.
Regarding 1. I was really just wondering if it'd be alright to create a function to return a value rather than just building the code in a void function. So I tried it and it worked, hence the change. From what I understood and saw that your protected override bool ProcessCmdKey, basically you wanted to see if the key was an arrow key. If it was return true. So what I did was basically if it's one of the selected colors, return a value corresponding to the color.
I was just hoping you could either help me understand the Serial and COM port connection or if you had a link for more explanation. Earlier when I was trying to send a string(On/Off) and then send a numeric(byte/int) to set a number of blink times, I couldn't figure out if the COM port is kind of like a singular channel. If I'm sending a string from the Windows Form, could I send out a int/byte in the same channel? Now that everything is of one keyword (byte) I can just create a byte array and figure out the communication between the Windows Form and Arduino. I'm a little confused about the underlying Serial aspect. When I saw your code I started to think a little differently.
In your code, if I'm understanding it properly, it seems that MyVCOM is how to communicate back and forth, just like port.Write. I believe it's singular as it's basically like the old telephone line, if I'm on a call, and you call try to call me, your call is blocked since my line is already being used.
So in your ConnReset, you want to make sure the COM's aren't open so you can set up communication. So your ConReset will clear the line if it's open already. What I'm confused about is the else part. If your port isn't open, open COM+PortNumber, so basically open the channel so you can communicate, but you declared port number to be 8, so shouldn't you just use:
MyVCOM.PortName = "COM8";
Where does the user select which COM? All of the communication is being done on COM8 isn't it? Or does is that part all part of a built in library? I believe all I need to do now is to send my byte array to my Arduino and then work on the Back End to take the data the Windows Form is sending.
public int Colorselection(string label3, int color) //Toggle a pin
{
if (label3 == "Red")
{
color = 6;
}
else if (label3 == "Green")
{
color = 5;
}
else if (label3 == "Blue")
{
color = 3;
}
return color;
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
String label4 = LEDColor.SelectedItem.ToString(); //Generate A string of selected Color
int xled = Colorselection(label4, color); //Toggle the string into an int
LEDLabel.Text = xled.ToString(); //Generate a string from the int
}
private void Run_Click(object sender, EventArgs e) //Generate byte to send instead of sending strings and int/byte
{
byte RGBLED = Convert.ToByte(color);
byte BlinkNum = Convert.ToByte(number1.Value);
byte BlinkDur = Convert.ToByte(number2.Value);
byte[] array2 = new byte[] { RGBLED, BlinkNum, BlinkDur };
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
/*
port.Open();
port.Write(array2, 0, 2);
port.Close();
*/
}
Your WinForms application assumes that your Arduino is connected to COM3. Do you know if that's actually the case, or is that sample code that you just copy and pasted? (Check the Windows Device Manager under COM ports to see what ports are available, then unplug/plug your device to see which port it's being mapped to)
Besides that, have you tried debugging your Arduino code on target to see what, if anything, is actually being received?
From the MS documentation, it's not clear how the SerialPort.Write command works exactly in terms of synchronization, so it may not be a great idea to close the port immediately after sending your command. Unfortunately, since I'm not in possession of an Arduino I can't test your code. But I did create a WinForms GUI to accomplish essentially the same task (and more that you probably don't need) several years ago that I've since posted to github (https://github.com/mbhul/RoboCOM). Let me know if that helps, otherwise please tell us more about your development environment.
All these comes from the idea that i want to use the SerialPort class in .Net , but the only way is by calling dll . Because i can only get interfaces from the program calling this dll. mycode is below.
i wrote a class about serialport,
public class CommClass
{
public SerialPort _port;
private string _receivedText;
public string receivedText
{
get { return _receivedText; }
set
{
_receivedText = value;
}
}
public CommClass(string _pname)
{
portList = SerialPort.GetPortNames();
_port = new SerialPort(portList[0]);
if (portList.Length < 1)
_port= null;
else
{
if(portList.Contains(_pname.ToUpper()))
{
_port = new SerialPort(_pname);
_port.DataReceived += new SerialDataReceivedEventHandler(com_DataReceived);
}
}
}
private void com_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
string indata = _port.ReadExisting();
receivedText = indata;
}
}
from Bytestoread i can see there r data coming in and i can get data from port.ReadExisting(), but receivedText did not change ,it did not hit the SerialDataReceived event . Is my way wrong?any suggestion?thanks
i created a dll from CommClass ,then i call it in my winform program which has a button and a textbox . Clicking the button , then i initialize the port
public Form1()
{
InitializeComponent();
}
public CommClass mycom;
private void button1_Click(object sender, EventArgs e)
{
mycom = new CommClass("com3");
mycom._port.Open();
textbox.Text=mycom.receivedText;//i add a breakpoint at this line ,
}
when hitting it , i check mycom._port.PortName is "com3", its IsOpen() is "Open" , i use virtual port to send data . i send "1111",then check the mycom._port.BytestoRead is 4, and mycom._port.ReadExisting() is "1111", but mycom.receivedText is null. My puzzle is that i have no idea when the data is coming . How to use the DataReceived event in my winform without code "using System.Io.Ports",just with reference CommClass.dll. Did i make it clear? Thanks for help.
mycom._port.Open();
textbox.Text=mycom.receivedText;//i add a breakpoint at this line ,
That code cannot work, it is a threading race bug. The DataReceived event does not fire instantly after you open the port. It will take a microsecond or so, give or take. A threadpool thread has to get started to fire the event. And of course the device actually has to send something, they usually only do so when you transmit something first.
Which clearly did not happen, your DataReceived event handler has a bug as well. It is not allowed to update the Text property of a control in that event since it runs on a worker thread. Your program will bomb with an InvalidOperationException.
You'll have to write something like this instead:
private void com_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
string indata = _port.ReadExisting();
this.BeginInvoke(new Action(() => {
textbox.AppendText(indata);
}));
}
With the additional stipulation that you must not leave it this way, updating the Text property of a TextBox and making it visible on the screen is an expensive operation that's going to turn your user interface catatonic when the device starts transmitting data at a high rate.
So, I'm trying to develop a simple application in visual C# which gets data from serial port and displays it in a textbox (to monitor temperature). I'm acquiring and displaying the data successfully, using the DataReceived event to update a global string variable and a timer to update the text field on my text box, as shown:
private void port_DataReceived_1(object sender, SerialDataReceivedEventArgs e)
{
try
{
globalVar.updateTemp = port.ReadLine(); //This is my global string
}
catch (IOException)
{
}
catch (InvalidOperationException)
{
}
catch (TimeoutException)
{
}
}
private void timer1_Tick(object sender, EventArgs e)
{
tempDisplayBox.Text = globalVar.updateTemp; //This is my textbox updating
}
The only issue I have is that the value shown in the textbox keeps flashing, making it hard to read. My timer is set to trigger every 10 ms (which should be fast enough, right?). Is there any way to make it more stable? I realize this may be a newb question, but to be fair I am a newb :) Any help is appreciated! Thanks!
Do you really need it updating every 10ms? What about every 500 ms or if not that then 100ms. 100ms will require your update method run 10 times less and therefore update 10 times less. The flickering you are expiriencing is due to the refresh speed. You could create custom method which will only update the temp only when target Label or textBox value is different than source port. But that will only sort the flickering when temp is steady, when temp will start vary it will bring back the flickering. Good luck ;-)
UPDATE
Hi I tried to reproduce the conditions and could not make my textbox nor Label flash. The way I tested it was by assigning int ntick = 0; and then increment the ++ntick; inside of the timer_tick method. The results didn't make any of the controls flash and were updated even every milisecond at some point. I also tried string.Format to put some load on the method. Is your app responsive?
The trick is to use double buffering. This way the operating system will redraw the Control off-screen, and only show the control when it is fully redrawn.
I have had the same problem, and solved it by extending the TextBox control like this:
public FastLogBox()
{
InitializeComponent();
_logBoxText = new StringBuilder(150000);
timer1.Interval = 20;
timer1.Tick += timer1_Tick;
timer1.Start();
SetStyle(ControlStyles.DoubleBuffer, true);
}
void timer1_Tick(object sender, EventArgs e)
{
if (_timeToClear)
{
_logBoxText.Clear();
_timeToClear = false;
}
if (_logQueue.Count <= 0) return;
while (!_logQueue.IsEmpty)
{
string element;
if (!_logQueue.TryDequeue(out element)) continue;
{
_logBoxText.Insert(0, element + "\r\n");
}
}
if (_logBoxText.Length > 150000)
{
_logBoxText.Remove(150000, _logBoxText.Length - 150001);
}
Text = _logBoxText.ToString();
}
public new void Clear()
{
_timeToClear = true;
while (!_logQueue.IsEmpty)
{
string element;
_logQueue.TryDequeue(out element);
}
}
public void AddToQueue(string message)
{
_logQueue.Enqueue(message);
}
}
I also use a timer and a concurrentQueue to avoid using Invoke to update the control from another thread. I also use a StringBuilder to prepare the string before putting it into the TextBox. StringBuilder is faster when building larger strings.
You can use ReadExisting() to read the whole data at a time.
You need to handle DataReceived Event of SerialPort
serialPort1.ReadExisting();
Sample:
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
String myData=serialPort1.ReadExisting();
}
Example Code: Here i would like to show you the code to Read Data(RFID Tag Code which is basically of length 12)
String macid = "";
private void DoWork()
{
Invoke(
new SetTextDeleg(machineExe ),
new object[] { macid });
macid = "";
}
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
string str1;
macid += serialPort1.ReadExisting();
if (macid.Length == 12)
{
macid = macid.Substring(0, 10);
Thread t = new Thread(new ThreadStart(DoWork));
t.Start();
}
}
public void machineExe(string text)
{
TextBox1.Text=text;
}
Thank you so much for the answers! I found a way to work around this issue:
Instead of replacing the contents of my textbox by rewriting the TextBox.Text property - which, as HenningNT implied, refreshes the control and causes the flickering - I'm now using the TextBox.AppendText method. Though, as I want to display only one line of data at a time, I use the textbox in multiline mode and the Environment.NewLine to jump to a new line before appending the text. As for the method of updating, I've gone back to using the timer because with the invoke method was crashing my application when I close the form, for some reason. Also, enabling double buffering didn't do me much good, although I guess I was doing it wrong... It still flickers a bit, but it's much better now :) I know this is not really a perfect solution (much more of a workaround), so I'll keep looking for it. If I find it, I'll be sure to update it here ;) My code:
private void timer1_Tick(object sender, EventArgs e) //Timer to update textbox
{
if (tempDisplayBox.Text != globalVar.updateTemp) //Only update if temperature is different
{
try
{
tempDisplayBox.AppendText(Environment.NewLine);
tempDisplayBox.AppendText(globalVar.updateTemp);
}
catch (NullReferenceException)
{
}
}
}