We Keep Coding

C# "Thread.Sleep" Messing My Program (Form Doesn't Show Up)

i add a loop to my program just to check something...(For verification)
for (int i = 1; i < total; i++){
for (int row = 0; row < 4; row++){
for (int col = 0; col < 4; col++){
pixel = block[i][row][col];
label1.Text = pixel.R.ToString("X");
System.Threading.Thread.Sleep(100);}}}
After Add this loop program works , but form doesnt show up. I Start Debuging and i saw that in this line it stops. Dont go any further.
Application.Run(new Form1());
Basicly begining of the program. So I isolate the System.Threading.Thread.Sleep(100);}}}
Part it is working now. Why this code is causing problem. I used the
using System.Threading.Tasks;.
Any idea or i can use other delay function... İ waiting for your help. Thank you..

You should never, ever, block the UI Thread (by means of sleeping or doing some heavy work) as the Thread can only either handle UI-Events (clicks, rerendering, resizing) or run your code, not both. In cases where you must execute some long running code from a event-handler, you can either start a new thread to do the work or run async code.
For you, something like this should work just fine:
public async void Form1_Load(object sender, EventArgs e) {
for (int i = 1; i < total; i++){
for (int row = 0; row < 4; row++){
for (int col = 0; col < 4; col++){
pixel = block[i][row][col];
label1.Text = pixel.R.ToString("X");
await Task.Delay();
}
}
}
}
While Sleep blocks the thread while it waits, await Task.Delay(); does not. It actually returns and lets the thread continue doing whatever it was doing previously and notifies the thread when it finished waiting so the thread can come back to your function later and continue running your code. (This is a simplification of how async and await works in C#)

Prevent hanging in windows forms

I'm having a problem.
So I've built an app which displays data in the form of chart and a datagridview. They are both responsive. That means they rescale and move with the data. It takes some computation power I guess.
At the same time I have timers cause it all runs periodically with f=4Hz.
And now: When I run the app and switch on the periodical readout the app hangs during resizing. How could I prevent it?
I've already tried to use a backgroundworker, but the problem occurs in the moment of accessing to the datagridview and chart which are declared (and also used) in the "other thread" (as the VS said)
So.. How could I prevent it?
Maybe I should utilise the backgroundworker in the other way?
My attempts with the backgroundworker:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
//Control.CheckForIllegalCrossThreadCalls = false;
if (!GetConnectionStatus())
{
stop_ticking();
if (MessageBox.Show("Device not connected", "Connection status", MessageBoxButtons.RetryCancel, MessageBoxIcon.Error) == DialogResult.Retry)
messaging();
else
return;
}
// TEMP READ
Read_temp(tlist);
float[] t = new float[3];
float[] r = new float[3];
float[] av = new float[1];
float[] st = new float[1];
// TEMP IMPORT
tlist.Give_current_temp(t, r, av, st);
string time_stamp = tlist.Give_current_time();
rows_nr++;
// ADDING TO GRID
dataGridView1.Invoke(new Action(() => { dataGridView1.Rows.Add(new object[] { rows_nr, time_stamp, av[0], st[0], (t[0]).ToString(), (r[0]).ToString(), (t[1]).ToString(), (r[1]).ToString(), (t[2]).ToString(), (r[2]).ToString() }); }));
//dataGridView1.Rows.Add(new object[] { rows_nr, time_stamp, av[0], st[0], (t[0]).ToString(), (r[0]).ToString(), (t[1]).ToString(), (r[1]).ToString(), (t[2]).ToString(), (r[2]).ToString() });
dataGridView1.Invoke(new Action(() => { dataGridView1.FirstDisplayedScrollingRowIndex = dataGridView1.RowCount - 1; }));
//dataGridView1.FirstDisplayedScrollingRowIndex = dataGridView1.RowCount - 1;
// ADDING TO CHART
for (int i = 0; i < 3; i++)
chart1.Invoke(new Action(() => { chart1.Series[series_names[i]].Points.AddXY((rows_nr), (t[i])); }));
//chart1.Series[series_names[i]].Points.AddXY((rows_nr), (t[i]));
chart1.Invoke(new Action(() => { chart1.Series["average"].Points.AddXY((rows_nr), (av[0])); }));
//chart1.Series["average"].Points.AddXY((rows_nr), (av[0]));
//chart1.Series["std1"].Points.AddXY((rows_nr), (av[0] + Math.Abs(st[0])));
//chart1.Series["std2"].Points.AddXY((rows_nr), (av[0] - Math.Abs(st[0])));
// MOVING CHART
if (chart1.Series[series_names[0]].Points.Count > nr_of_noints_graph)
{
for (int i = 0; i < 3; i++)
chart1.Series[series_names[i]].Points.RemoveAt(0);
chart1.Series["average"].Points.RemoveAt(0);
//chart1.Series["std1"].Points.RemoveAt(0);
//chart1.Series["std2"].Points.RemoveAt(0);
chart1.ChartAreas[0].AxisX.Minimum = rows_nr - (nr_of_noints_graph - 1);
chart1.ChartAreas[0].AxisX.Maximum = rows_nr;
dataGridView1.Rows.RemoveAt(0);
}
chart1.Invoke(new Action(() => { chart1.ChartAreas[0].RecalculateAxesScale(); }));
//chart1.ChartAreas[0].RecalculateAxesScale();
}

Please take a look at background worker sample. You are doing it wrong. Background worker DoWork should not call UI controls and is executed in non UI thread, it should execute time consuming computing and call worker.ReportProgress(). While ReportProgress method can access UI controls and code in this method is executed in UI thread.
Some chart controls are lugging when adding/removing points. Maybe it hangs because it lugs. Make updates less frequently (1 in 1 second for example) and see whether it hangs or not.
https://learn.microsoft.com/en-us/dotnet/api/system.componentmodel.backgroundworker?view=netframework-4.7.2
Wrap operations in Stopwatch and use System.Diagnostics.Debug.WriteLine to trace execution flow and time spent on the operations.
Moving chart part does not work because it accesses UI elements in non ui thread without Invoke to UI thread.
If it was not Background worker I would write it this way:
// MOVING CHART
chart1.Invoke(new Action(()=>
{
if (chart1.Series[series_names[0]].Points.Count > nr_of_noints_graph)
{
for (int i = 0; i < 3; i++)
chart1.Series[series_names[i]].Points.RemoveAt(0);
chart1.Series["average"].Points.RemoveAt(0);
chart1.ChartAreas[0].AxisX.Minimum = rows_nr - (nr_of_noints_graph - 1);
chart1.ChartAreas[0].AxisX.Maximum = rows_nr;
}
}
));
I wouldn't wrap each operation in separate Invokes as well.
As for your question it's insufficient information to detect what is wrong please provide minimum viable runnable sample which demonstrates the problem.

As #Access Denied states you should improve separation between GUI and Background worker threads. You could execute // TEMP READ and // TEMP IMPORT operations on background thread and make a call to the GUI thread via .Invoke method when all the data is ready. Read "How to: Make Thread-Safe Calls to Windows Forms Controls" article for more information.
When you add/update data in your DataGridView use .BeginUpdate/.EndUpdate methods to prevent control update until all the data is refreshed.
Other approach is to use Virtual mode. It's especially usefull if you have many items in grid.

When working with a background thread you must not create, update, or even access any UI element.
You need to separate the work that retrieves your data (the slow part) from the work that updates the chart (which is very fast).
It really comes down to doing it like this:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
if (!GetConnectionStatus())
{
stop_ticking();
return;
}
// TEMP READ
Read_temp(tlist);
float[] t = new float[3];
float[] r = new float[3];
float[] av = new float[1];
float[] st = new float[1];
// TEMP IMPORT
tlist.Give_current_temp(t, r, av, st);
string time_stamp = tlist.Give_current_time();
rows_nr++;
chart1.Invoke(new Action(() =>
{
// ADDING TO GRID
dataGridView1.Rows.Add(new object[] { rows_nr, time_stamp, av[0], st[0], (t[0]).ToString(), (r[0]).ToString(), (t[1]).ToString(), (r[1]).ToString(), (t[2]).ToString(), (r[2]).ToString() });
dataGridView1.FirstDisplayedScrollingRowIndex = dataGridView1.RowCount - 1;
// ADDING TO CHART
for (int i = 0; i < 3; i++)
{
chart1.Series[series_names[i]].Points.AddXY((rows_nr), (t[i]));
}
chart1.Series["average"].Points.AddXY((rows_nr), (av[0]));
// MOVING CHART
if (chart1.Series[series_names[0]].Points.Count > nr_of_noints_graph)
{
for (int i = 0; i < 3; i++)
{
chart1.Series[series_names[i]].Points.RemoveAt(0);
}
chart1.Series["average"].Points.RemoveAt(0);
chart1.ChartAreas[0].AxisX.Minimum = rows_nr - (nr_of_noints_graph - 1);
chart1.ChartAreas[0].AxisX.Maximum = rows_nr;
dataGridView1.Rows.RemoveAt(0);
}
chart1.ChartAreas[0].RecalculateAxesScale();
}));
}
If you have to show a MessageBox then you also need to invoke that.

Threading not working?

So! I am just playing around with progress bars in winForm but I noticed something. If I use a For statement the progress bar goes from 0 - 100 instant, even if I put a EX: Thread.Sleep(10000); It waits the time and then goes too 100%.
What am I doing wrong?
public void progressbar(object sender, EventArgs e)
{
for (int i = 0 ; i < 100; i++)
{
Thread.Sleep(10);
progressBar1.Value = i;
}
}

You're blocking the UI thread. While your event handler is running, your window can't handle any incoming window messages, so it will not update, and it will not repaint. Don't block the UI thread.

You need to update every interaction your progressbar. Note also that in your for, will go to 90 only and not to 100. Try this code:
for (int i = 0; i <= 100; i++)
{
Thread.Sleep(10);
progressBar1.Value = i;
progressBar1.Refresh();
}
EDIT:
To work you must put in some event such as the click of a button , never in a Form Load

Can't change the text on an object?

I can't seem to change the text on any object - I've tried both labels and buttons so far. Why doesn't this work?
void Button1Click(object sender, EventArgs e)
{
for(int i = 60; i >=1; i--){
Thread.Sleep(1000);
i -= 1;
label1.Text = i.ToString();
}
}

It doesn't work because you are using a busy loop to update the text.
This code runs in the main thread, so it's busy setting the Text property for a whole minute, and can't update the user interface.
You would use a timer to update the text, so that the main thread regains the control in between changes.

Try taking out the Thread.Sleep() command to see if the label is updated. You may find that the UI thread exits the function even though you requested it to sleep.
What you can do is use a Timer control, and set the interval to 1000 (1 second). Then you can set the label1.Text to a counter or static field value (or hidden field).

As long as you stay in the Button1Click the UI thread seams to be sleeping. Delete the Thread.Sleep and you will see that the text is shown in the labels.

put Application.DoEvents(); in your code after last line, then it will work for sure.
for (int i = 60; i >= 1; i--)
{
Thread.Sleep(1000);
i -= 1;
label1.Text = i.ToString();
Application.DoEvents();
}

First of all you have to learn How to: Make Thread-Safe Calls to Windows Forms Controls.
You need to create a thread and use Invoke delegate.
Thread th = new Thread(test);
th.Start(); //start the thread
This method will update the lable.text
void test()
{
for (int i = 60; i >= 1; i--)
{
Thread.Sleep(1000);
if (label1.InvokeRequired)
{
label1.Invoke(new Action(() => {
label1.Text = i.ToString();
}));
}
}
}

Threading issues using Ping to map active IPs - C#

I am trying to create a simple Network Tool to ping all possible IPs on your local subnet and provide a list of such IPs in a DataGridView. I am new to having to consider threading which is a good thing to come across as a budding programmer. Sorry, but you are probably going to have to do some explaining to me, but in my mind this should work. Before I tried putting it in a backgroundworker thread, the application would just hang and give me a "Not Responding".
thanks ahead of time.
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
count = 0;
for (int j = 1; j < 255; j++)
for (int i = 1; i < 255; i++)
{
Ping ping = new Ping();
PingReply pingreply = ping.Send(IPAddress.Parse(locip[0] + "." + locip[1] + "." + j + "." + i));
if (pingreply.Status == IPStatus.Success)
{
status = "o";
repAddress = pingreply.Address.ToString(); ;
repRoundtrip = pingreply.RoundtripTime.ToString();
repTTL = pingreply.Options.Ttl.ToString();
repBuffer = pingreply.Buffer.Length.ToString();
string[] lineBuffer = { status, repAddress, repRoundtrip, repTTL, repBuffer };
ipList.Rows.Add(lineBuffer);
count += 1;
progressBar.Value += 1;
}
}
}

You cannot access directly the progressBar1 (or any other UI element) from the backgroundWorker1 "DoWork" event, you have to use the backgroundWorker1.ProgressChanged method and handle ProgressChanged event:
// instead of progressBar.Value += 1
// use the following
const int total = 254 * 254;
backgroundWorker1.ReportProgress(count / total);
WorkerReportsProgress should be assigned to true
and the event of ProgressChanged to the following method
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
// assuming the Minimum = 0 and Maximum = 100 on progressBar
progressBar.Value = e.ProgressPercentage;
}

Part of the problem is that you are directly accessing a UI element from your background thread. The field progressBar is presumably a UI progress bar control and can only be safely accessed from the UI thread. You must use a call to .Invoke to set this value from the UI thread.
progressBar.Invoke(new MethodInvoker(UpdateProgressBarbyOne));
...
private void UpdateProgressBarByOne() {
progressBar.Value += 1;
}

Ah I love threading. It makes programs so much more interesting...
So as I started off learning about how to make responsive applications I came across the function: Application.DoEvents()
(http://msdn.microsoft.com/en-us/library/system.windows.forms.application.doevents.aspx)
What this does is causes your form to process some of the window events it's receiving. I think that your code could change to include a call after each ping request...
i.e. within the on click event handler
count = 0;
for (int j = 1; j < 255; j++)
for (int i = 1; i < 255; i++)
{
Ping ping = new Ping();
PingReply pingreply = ping.Send(IPAddress.Parse(locip[0] + "." + locip[1] + "." + j + "." + i));
if (pingreply.Status == IPStatus.Success)
{
status = "o";
repAddress = pingreply.Address.ToString(); ;
repRoundtrip = pingreply.RoundtripTime.ToString();
repTTL = pingreply.Options.Ttl.ToString();
repBuffer = pingreply.Buffer.Length.ToString();
string[] lineBuffer = { status, repAddress, repRoundtrip, repTTL, repBuffer };
ipList.Rows.Add(lineBuffer);
count += 1;
progressBar.Value += 1;
}
Application.DoEvents(); //but not too often.
}
Now this was back in the pre dot net days and it's survived till now however, it's not something that you should take lightly. If you click another button on the form it will start off another thread that will attempt to execute and if you're not careful cause thread exceptions on your form. Some developers will tell you don't use this but since your starting off I'd say give it a shot :)
I might not use this method depending on the application. Instead what I would do it actually do is to create several processing "trains"; one for each cpu core that the system had. I'd add the ips to be scanned to a queue object and then I would start up 2 to 4 instances of threads (http://msdn.microsoft.com/en-us/library/system.threading.thread.aspx) each of which taking an item off the queue in turn, process the information (i.e. do the ping logic) and put the result on another queue; and output queue. Every time a train would finish an item for work it would raise an event at the other end of which there would be a handler in the form. Using the Invoke to make thread safe calls (http://msdn.microsoft.com/en-us/library/ms171728.aspx) on my form I would update the UI's information accordingly.
Threading is fun dude :) over time you can find that you can use MSMQ to make a system that uses the multicores of other computers to do jobs such as image processing (or something with pa....... ;)