Good day. In my application there is a treeview and the nodes indicate the data to connect via tcp. I want the display of these connections to start when the form is displayed.
I added an asynchronous function, but it comes to my check and its execution ends.
public async void checkConnect()
{
for (int i = 0; i < treeView1.Nodes.Count; i++)
{
string result = await Task.Factory.StartNew<string>(() => connectTread(), TaskCreationOptions.LongRunning);
}
}
public string connectTread()
{
string ret = "";
string[] IpHERE;
foreach (TreeNode child in treeView1.Nodes)
{
IpHERE = child.Text.Split(' ');
Modbus mb = new Modbus();
Regex regIP = new Regex(#"\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b");
if (regIP.IsMatch(IpHERE[1]) && IpHERE[1].Length != 0 && IpHERE[4].Length != 0 && IpHERE[9].Length != 0 && IpHERE[11].Length != 0 && (mb.OpenTCP(IpHERE[1], IpHERE[4], IpHERE[9], IpHERE[11])))
{
child.SelectedImageIndex = 3;
mb.CloseTCP();
ret = "Ok";
}
else
{
child.SelectedImageIndex = 4;
ret = "Error";
}
}
return ret;
}
I want the display of these connections to start when the form is displayed.
When the form is first displayed, you must display the data immediately. You should initialize the display with some kind of a "Loading..." value or spinner or something, and start the asynchronous operation(s) when the form is displayed.
Then, later, when the asynchronous operation(s) complete, then update the data in the form with the actual data.
P.S. Avoid async void and use Task.Run instead of StartNew.
Related
I'm having this little problem with some easy code, basically what I'm doing is sending information via the serial port via a program I wrote in Java. The information is getting their for basic statements (IE, can turn on lights and stuff) but I'm having errors getting it to decode strings with number values send to it.
So for example, I'm sending strings that look like this
BS//:+000/+000/+000
and the decoding method I'm using looks like this.
After adding the string via this:
if (inputString.startsWith("BS//:")) //**fixed
{
inputInfoToBaseStepper(inputString);
baseStepperRunAction(baseStepperRotCount, baseStepperRotStepSize, baseStepperTime);
}
Sends it too...
void inputInfoToBaseStepper(String baseStepper)
{
baseStepperRotCount = baseStepper.substring(6,9).toInt();
baseStepperRotStepSize = baseStepper.substring(10,13).toInt();
baseStepperTime = baseStepper.substring(15,18).toInt();
}
Which should decode and run
void baseStepperRunAction (int rotations, int StepSize, int delayTime)
{
for (int rotations; rotations >=0; rotations--)
{
baseStepper.step(StepSize);
delay(delayTime);
}
}
Problem seems to be that it doesn't decode... ideas I'm sort of lost at this stage. :/
(total past of the code, I know the information is getting there, just not compiling like it should.)
#include <Stepper.h>
//#include <HardwareSerial.h>
// int intensity = 0; // led intensity this is needed just as example for this sketch
String inputString = ""; // a string to hold incoming data (this is general code you can reuse)
boolean stringComplete = false; // whether the string is complete (this is general code you can reuse)
int stepsPerRevolution = 64; //at 5.625 degrees a step
// initialize the stepper library on pins 8 through 11:
Stepper baseStepper(stepsPerRevolution, 2,3,4,5); // protocols start with //BS:
Stepper shoulderStepper(stepsPerRevolution, 6,7,8,9); // protocols start with //SS:
Stepper armStepper(stepsPerRevolution, 10,11,12,13); // protocols start with //AS:
//--------baseStepper--------//
int baseStepperRotCount = 0; //how many rotations in the for loop is needed
int baseStepperRotStepSize = 0; // how large should the steps be...
int baseStepperTime = 0; //delay time needed between each step (delay); so the stepper can do it's work.
//--------shoulderStepper--------//
int shoulderStepperRotCount =0;
void setup() {
// initialize serial: (this is general code you can reuse)
Serial.begin(115200);
}
void loop() {
// when a newline arrives:
if (stringComplete) {
//these are test if statements, they serve no purpose after the intial boot, but must be included to test the connectivity;
if (inputString.startsWith("alpha"))
{
boolean msgRecognized = true;
pinMode(13, OUTPUT);
digitalWrite(13, HIGH);
inputString = "";
stringComplete = false;
}
else if (inputString.startsWith("beta"))
{
boolean msgRecognized = true;
pinMode(13, OUTPUT);
digitalWrite(13, LOW);
inputString = "";
stringComplete = false;
}
//---------------------///
//these statements set the engines and prepare for running of the program.
if (inputString.startsWith("//BS:")) // "BS//:+000/+000/+000"
{
inputInfoToBaseStepper(inputString);
baseStepperRunAction(baseStepperRotCount, baseStepperRotStepSize, baseStepperTime);
}
else if (inputString.startsWith("//SS:"))
{
//inputInfoToShoulderStepper();
//outputConfirmed();
}
else if (inputString.startsWith("//AS:"))
{
//inputInfoToArmStepper();
// outputConfirmed();
}
if(inputString.startsWith("alp://")) { // OK is a message I know (this is general code you can reuse)
boolean msgRecognized = true;
if(inputString.substring(6,10) == "kprs") { // KeyPressed }
msgRecognized = false; // this sketch doesn't know other messages in this case command is ko (not ok)
// Prepare reply message if caller supply a message id (this is general code you can reuse)
int idPosition = inputString.indexOf("?id=");
if(idPosition != -1) {
String id = inputString.substring(idPosition + 4);
// print the reply
Serial.print("alp://rply/");
if(msgRecognized) { // this sketch doesn't know other messages in this case command is ko (not ok)
Serial.print("ok?id=");
} else {
Serial.print("ko?id=");
}
Serial.print(id);
Serial.write(255); // End of Message
Serial.flush();
}
}
// clear the string:
inputString = "";
stringComplete = false;
}
}
}
/*
Send listen messages
int index = 0;
for (index = 0; index < digitalPinListeningNum; index++) {
if(digitalPinListening[index] == true) {
int value = digitalRead(index);
if(value != digitalPinListenedValue[index]) {
digitalPinListenedValue[index] = value;
Serial.print("alp://dred/");
Serial.print(index);
Serial.print("/");
Serial.print(value);
Serial.write(255);
Serial.flush();
}
}
}
for (index = 0; index < analogPinListeningNum; index++) {
if(analogPinListening[index] == true) {
int value = analogRead(index);
if(value != analogPinListenedValue[index]) {
analogPinListenedValue[index] = value;
Serial.print("alp://ared/");
Serial.print(index);
Serial.print("/");
Serial.print(value);
Serial.write(255); // End of Message
Serial.flush();
}
}
}
} */
//this method decodes and stores inputs
void inputInfoToBaseStepper(String baseStepper)
{
baseStepperRotCount = baseStepper.substring(6,9).toInt(); // B S / / : + 0 0 0 / + 0 0 0 / + 0 0 0
baseStepperRotStepSize = baseStepper.substring(10,13).toInt();// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8
baseStepperTime = baseStepper.substring(15,18).toInt();
}
//this method runs the base stepper off the decoded actions.
void baseStepperRunAction (int rotations, int StepSize, int delayTime)
{
for (int rotations; rotations >=0; rotations--)
{
baseStepper.step(StepSize);
delay(delayTime);
}
}
/*
SerialEvent occurs whenever a new data comes in the
hardware serial RX. This routine is run between each
time loop() runs, so using delay inside loop can delay
response. Multiple bytes of data may be available.
This is general code you can reuse.
*/
void serialEvent() {
while (Serial.available() && !stringComplete) {
// get the new byte:
char inChar = (char)Serial.read();
// add it to the inputString:
inputString += inChar;
// if the incoming character is a newline, set a flag
// so the main loop can do something about it:
if (inChar == '\n') {
stringComplete = true;
}
}
}
I want to show only few rows in DataGridview (like 1 to 10) and remaining are shown on button click..
so How can I Perform this operation..
If you have all data loaded (that means you are not doing paging on DB side for example) then keep track of page;
private int page = 0;
protected void ShowNextResults_Click(object sender, EventArgs e)
{
page++;
dataGridView1.CurrentCell = null; //required to control row visibility as we cannot hide current cell
int from = page * 10;
int to = from + 10;
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
if (i >= from || i < to)
{
dataGridView1.Rows[i].Visible = true;
}
else
{
dataGridView1.Rows[i].Visible = false;
}
}
}
This traverse results forward but it should be very easy to implement backwards moving.
This following code gives me the error below . I think I need "InvokeRequired" . But I don't understand how can I use?
error:Cross-thread operation not valid: Control 'statusBar1' accessed from a thread other than the thread it was created on.
the code :
public void CalculateGeneration(int nPopulation, int nGeneration)
{
int _previousFitness = 0;
Population TestPopulation = new Population();
for (int i = 0; i < nGeneration; i++)
{
if (_threadFlag)
break;
TestPopulation.NextGeneration();
Genome g = TestPopulation.GetHighestScoreGenome();
if (i % 100 == 0)
{
Console.WriteLine("Generation #{0}", i);
if ( ToPercent(g.CurrentFitness) != _previousFitness)
{
Console.WriteLine(g.ToString());
_gene = g;
statusBar1.Text = String.Format("Current Fitness = {0}", g.CurrentFitness.ToString("0.00"));
this.Text = String.Format("Sudoko Grid - Generation {0}", i);
Invalidate();
_previousFitness = ToPercent(g.CurrentFitness);
}
if (g.CurrentFitness > .9999)
{
Console.WriteLine("Final Solution at Generation {0}", i);
statusBar1.Text = "Finished";
Console.WriteLine(g.ToString());
break;
}
}
}
}
Easiest for reusability is to add a helper function like:
void setstatus(string txt)
{
Action set = () => statusBar1.Text = txt;
statusBar1.Invoke(set);
}
Or with the invokerequired check first:
delegate void settextdelegate(string txt);
void setstatus(string txt)
{
if (statusBar1.InvokeRequired)
statusBar1.Invoke(new settextdelegate(setstatus), txt);
else
statusBar1.Text = txt;
}
Either way the status can then be set like
setstatus("Finished");
For completeness I should add that even better would be to keep your calculating logic separated from your form and raise a status from within your calculating functionality that can be hanled by the form, but that could be completely out of scope here.
I need to test a Data Context and see what behavior it has under multiple simultaneous requests, for that I made a simple console application that [in theory] would send these requests:
private static DateTime startTime = DateTime.Now.AddSeconds(5);
public static Random rand = new Random();
static void Main(string[] args)
{
const byte testThreads = 10;
ThreadStart[] threadStarts = new ThreadStart[testThreads];
Thread[] threads = new Thread[testThreads];
for (byte i = 0; i < testThreads; i++)
{
threadStarts[i] = new ThreadStart(ExecutePOST);
threads[i] = new Thread(threadStarts[i]);
}
for (byte i = 0; i < testThreads; i++){ threads[i].Start(); }
for (byte i = 0; i < testThreads; i++){ threads[i].Join(); }
}
The called function is
private static void ExecutePOST()
{
while (DateTime.Now < startTime) { }
Console.WriteLine("{0} STARTING TEST", DateTime.Now.Millisecond);
WebRequest webRequest = WebRequest.Create(/*URL*/);
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.Method = "POST";
string name = string.Format("Test {0}", Program.rand.Next(1000));
byte[] bytes = Encoding.ASCII.GetBytes(/*PARAMETERS*/);
Stream output = null;
try
{
webRequest.ContentLength = bytes.Length;
output = webRequest.GetRequestStream();
output.Write(bytes, 0, bytes.Length);
Console.WriteLine("{0}:{1}", DateTime.Now.Millisecond, name);
}
catch (WebException ex)
{
Console.WriteLine(ex.Message);
}
finally
{
if (output != null)
{
output.Close();
}
}
}
The output I get is:
Can anyone please explain this behavior? Why is it stopping after two requests?
Thank you
Yes, this is because the number of connections per URL is limited to 2 by default - the connections are pooled.
You're hogging the connection by writing data to the request stream, but then never getting the response. A simple:
using (webRequest.GetResponse()) {}
at the end of the method is likely to sort it out. That will finish the request and release the connection to be used by another request.
Also note that a using statement for the output stream would make your code simpler too.
I am trying to retrieve a random number of users from the UserProfileManager.
But I am encountering errors when deploying to the live servers. I can't seem to see what is causing the error. My code is below:
for (int i = 0; i < NumberOfUserLimit; i++)
{
UserProfile up = profileManager.GetUserProfile(random.Next(1, NumberOfUserLimit));
if (up["FirstName"] != null && up["FirstName"].Value != null && !String.IsNullOrEmpty(up["FirstName"].Value.ToString()))
{
DataRow drUserProfile;
drUserProfile = dtUserProfile.NewRow();
drUserProfile["DisplayName"] = up.DisplayName;
drUserProfile["FirstName"] = up["FirstName"].Value;
drUserProfile["LastName"] = up["LastName"].Value;
drUserProfile["Department"] = up["Department"].Value;
drUserProfile["Location"] = up["SPS-Location"].Value;
drUserProfile["HireDate"] = up["SPS-HireDate"].Value;
drUserProfile["ContactNumber"] = up["Office"].Value;
if (up["PictureURL"] != null && up["PictureURL"].Value != null && !String.IsNullOrEmpty(up["PictureURL"].Value.ToString()))
{
string cleanAccountName = up["AccountName"].Value.ToString().Replace(#"\", "_");
string pictureUrl = String.Format("https://my.someintranet.com/User Photos/Profile Pictures/{0}_MThumb.jpg", cleanAccountName);
drUserProfile["Image"] = pictureUrl;
}
else
{
drUserProfile["Image"] = "~/_layouts/images/O14_person_placeHolder_96.png";
}
drUserProfile["MySiteUrl"] = up.PublicUrl;
dtUserProfile.Rows.Add(drUserProfile);
}
}
My code works when I apply a simple foreach to my code above instead of the "for loop":
foreach (UserProfile up in profileManager)
Which proves I can return userprofiles.
Any help is appreciated.
profileManager.GetUserProfile(long recordId)
expects a recordId from userprofile table. It is not an index, so you cannot use "random".
If you want to check RecordId, you can take a look at SQL tables of ProfileDB. Table "UserProfile_Full" has MasterRecordId column. Your parameter in GetUserProfile has to match of the user profile's MasterRecordId.
you can use the following code to get your random profiles:
IEnumerator profiles = profileManager.GetEnumerator();
int index = new Random().Next(1, 100);
while (index >= 0 && profiles.MoveNext())
index--;
UserProfile currentProfile = (UserProfile)profiles.Current
Code that handles Random better
public class TestClass
{
private random = new Random();
private long totalNumberOfProfiles; //ProfileManager.Count not always returns count correctly
public TestClass()
{
//this does not have to be in constructor but point is to have it cached (reasonably)
IEnumerator profiles = profileManager.GetEnumerator();
long counter = 0;
while (profiles.MoveNext())
counter++;
this.totalNumberOfProfiles = counter;
}
public fillInDataSet()
{
//something is here...
IEnumerator profiles = profileManager.GetEnumerator();
int index = random.Next(1, totalNumberOfProfiles);
while (index >= 0 && profiles.MoveNext())
index--;
UserProfile currentProfile = (UserProfile)profiles.Current
//something is here...
}
}