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Stop and repeat process by using a timer in C# Windows Form

I am trying to use a timer to achieve a sort of old animation used in the past to show that a process is running.
The way I would like to do that is by adding dots to a sentence (in a label control), for example:
"Process is running." to "Process is running.." and "Process is running..." with a limit of 3 dots and then revert back to a single dot.
I am not sure as to the fact using a timer here would be the best choice, but I thought it should work fine for such a simple example.
The code I used is as follows:
public string InitialProcessText;
private void StartBtn_Click(object sender, EventArgs e)
{
if(fileName != "No file selected")
{
ValidationLbl.Text = null;
ProcessLbl.Text = "Application is now running.";
//InitialProcessText = ProcessLbl.Text;
ProcessTimer.Start();
}
else
{
ValidationLbl.Text = "No file was added";
}
}
private void StopBtn_Click(object sender, EventArgs e)
{
ProcessTimer.Stop();
}
private void ProcessTimer_Tick(object sender, EventArgs e)
{
_ticks++;
//For every two ticks, ProcessLbl.Text = InitialProcessText
ProcessLbl.Text += ".";
}
What could I add to set a limit of adding 2 dots and then remove the dots and add dots again (I would assume to do this in the ProcessTimer_Tick method)?

You can just use your _ticks variable:
private readonly int _ticksPerUpdate = 2;
private readonly int _maxNumberOfDots = 3;
private void ProcessTimer_Tick(object sender, EventArgs e)
{
_ticks++;
if(_ticks == (_ticksPerUpdate * (_maxNumberOfDots + 1)))
{
_ticks = 0;
ProcessLbl.Text = InitialProcessText;
}
else if(_ticks % _ticksPerUpdate == 0)
{
ProcessLbl.Text += ".";
}
}
Remember to reset the ticks counter every time you start the timer:
private void StartBtn_Click(object sender, EventArgs e)
{
if(fileName != "No file selected")
{
ValidationLbl.Text = null;
ProcessLbl.Text = "Application is now running.";
InitialProcessText = ProcessLbl.Text;
// reset the variable
_ticks = 0
ProcessTimer.Start();
}
else
{
ValidationLbl.Text = "No file was added";
}
}

I assume that _ticks counts the number of ticks. You could then go :
if(ticks%3 == 0)
{
ProcessLbl.Text = "Application is now running."
}
else
{
ProcessLbl.Text+=".";
}
Then, at 1st tick, 1%3=1 so it adds a dot, at 2nd tick, 2%3=2 so it adds a dot and 3rd tick, 3%3=0, so it gets back to original.

Just because...here's another approach:
private void ProcessTimer_Tick(object sender, EventArgs e)
{
ProcessLbl.Text = ProcessLbl.Text.EndsWith("...") ? ProcessLbl.Text.TrimEnd(".".ToCharArray()) + "." : ProcessLbl.Text + ".";
}

How to capture Enter key in a ListBox control?

I read articles over the internet but I think I'm missing something here. I tried following the answer to this SO question, but nothing has happened.
I wanted to trigger the usePort_Click method whenever I press the Enter/Return key. Also, I don't know how to get around the EventArgs parameter of usePort_Click whenever I do try calling it from the ports_Keydown method.
Note: ports is a ListBox control.
private void usePort_Click(object sender, EventArgs e)
{
try
{
port = new SerialPort((string)ports.SelectedItem, 9600);
portUsedLabel.Text = (string)ports.SelectedItem;
String buffer = "";
String tellArduino = "food"; // test value
port.Open();
port.WriteLine(tellArduino);
for (int x = 0; x < tellArduino.Length; x++)
{
buffer += port.ReadLine();
}
ports.Items.Add(buffer);
port.Close();
}
catch { //stuff }
}
private void ports_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
//code here
}
}

A good solution would be to move the code you want to execute into a separate method (I called it someStuff, replace the name with something better) and call that method from both event handlers:
private void usePort_Click(object sender, EventArgs e)
{
someStuff();
}
private void ports_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
someStuff();
}
}
private void someStuff()
{
try
{
port = new SerialPort((string)ports.SelectedItem, 9600);
portUsedLabel.Text = (string)ports.SelectedItem;
String buffer = "";
String tellArduino = "food"; // test value
port.Open();
port.WriteLine(tellArduino);
for (int x = 0; x < tellArduino.Length; x++)
{
buffer += port.ReadLine();
}
ports.Items.Add(buffer);
port.Close();
}
catch { //stuff }
}

Where to declare queues in separate event handlers

Hi I am trying to use the queue function in my program for a mini game that receives X,Y,Z acceleration from an accelerometer.
However I don't know where I should or how I should declare the queue to make it accessible in two separate event handler.
As you can see I tried multiple attempts and declaring it in both the private event handlers was my last attempt.
Any help is appreciated. Thanks!
Here's my current code:
public Form1()
{
InitializeComponent();
ConnectedComPortUpdate();
serialPort1.DataReceived += DataReceivedHandler;
comboBox1.DropDown += comboBox1_DropDown;
}
private void comboBox1_DropDown(object sender, EventArgs e)
{
ConnectedComPortUpdate();
}
private void Clock_Tick(object sender, EventArgs e)
{
int xAccel;
int yAccel;
int zAccel;
Queue<int> myXQueue = new Queue<int>();
Queue<int> myYQueue = new Queue<int>();
Queue<int> myZQueue = new Queue<int>();
while( myXQueue.Count!=0 && myYQueue.Count!=0 && myZQueue.Count!=0 );
{
xAccel = myXQueue.Dequeue();
yAccel = myYQueue.Dequeue();
zAccel = myZQueue.Dequeue();
this.BeginInvoke(new EventHandler(delegate
{
XAccel.Text = xAccel.ToString("000");
YAccel.Text = yAccel.ToString("000");
ZAccel.Text = zAccel.ToString("000");
}));
}
}
private void ConnectedComPortUpdate()
{
//Clears COM List
comboBox1.Items.Clear();
//Accesses System Port Information and Adds it to the ComboBox
comboBox1.Items.AddRange(System.IO.Ports.SerialPort.GetPortNames().ToArray());
//Selects the last and "first" device
try
{
comboBox1.SelectedIndex = 0;
}
catch (ArgumentOutOfRangeException)
{
MessageBox.Show("Please plug in your tiny stick");
comboBox1.Text = (" ");
}
}
private void button1_Click(object sender, EventArgs e)
{
if (!serialPort1.IsOpen)
{
try
{
serialPort1.PortName = comboBox1.Text;
serialPort1.Open();
comboBox1.Enabled = false;
butPortState.Text = "Disconnect";
MessageBox.Show(String.Format("You selected port '{0}'", serialPort1.PortName));
}
catch
{
MessageBox.Show("Please select a serial port from the drop down list");
}
}
else
{
if (serialPort1.IsOpen)
{
serialPort1.Close();
comboBox1.Enabled = true;
butPortState.Text = "Connect";
}
}
}
private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
int currentDataByte = 0;
int byteToRead;
int xAccel = 0;
int yAccel = 0;
int zAccel = 0;
Queue<int> myXQueue = new Queue<int>();
Queue<int> myYQueue = new Queue<int>();
Queue<int> myZQueue = new Queue<int>();
while (serialPort1.IsOpen && serialPort1.BytesToRead != 0)
{
try
{
byteToRead = serialPort1.ReadByte();
}
catch
{
byteToRead = 0;
}
if (byteToRead == 255)
{
currentDataByte = 0;
}
else
{
currentDataByte++;
switch (currentDataByte)
{
case 1:
myXQueue.Enqueue(byteToRead);
xAccel = byteToRead;
break;
case 2:
myYQueue.Enqueue(byteToRead);
yAccel = byteToRead;
break;
case 3:
myZQueue.Enqueue(byteToRead);
zAccel = byteToRead;
break;
}
}
}
}
}
}

You would need the queues to be declared at the class/instance level:
// These can now be used in all event handlers...
Queue<int> myXQueue = new Queue<int>();
Queue<int> myYQueue = new Queue<int>();
Queue<int> myZQueue = new Queue<int>();
public Form1()
{
InitializeComponent();
ConnectedComPortUpdate();
serialPort1.DataReceived += DataReceivedHandler;
comboBox1.DropDown += comboBox1_DropDown;
}
private void comboBox1_DropDown(object sender, EventArgs e)
{
ConnectedComPortUpdate();
}
private void Clock_Tick(object sender, EventArgs e)
{
int xAccel;
int yAccel;
int zAccel;

I don't think the answer to this question (or even the question itself) is C# specific necessarily. Consider the question "Where should I declare variable X" The answer is almost always "In the narrowest scope possible that's accessible every place that needs to use variable X"
In your case, the answer may be "At the class level"
Alternatively, if you were to program in a more functional style the answer may be "Reconsider the structure of the program so that X can be passed as a parameter to the functions that need it". Most C# event handler have a place where you can stick a "user state" object so that it can be passed along from event source to event handler.
The answer would be the same in C, C++, java, etc.
(Perhaps this should be a comment, but I'm afraid it's a bit long)

BackgroundWorker for implementing "Search as you type" Combobox

I have created a code for my combobox, that can search addresses in a very large table on Sql Server with the help of stored procedure (i'm working with Entity framework). My stored procedure returns 10 hits and my code fills the combobox with search results. For doing this I'm using BackgroundWorker.
But here I'm now having big problems:
- although the combobox is filled with my search results, it always has the first item selected. Even if I type in only a letter, the whole text gets selected;
After that searching for the address doesn't work anymore. It searches only among these 10 results and I'm having no idea how to solve this. Here is my whole code, that causes me problems:
public String searchedItem = "";
public delegate void DelegateUpdateComboboxSelection(ComboBox myCombo,string value,int count);
BackgroundWorker m_bgworker = new BackgroundWorker();
static AutoResetEvent resetWorker = new AutoResetEvent(false);
m_bgworker.WorkerSupportsCancellation = true;
m_bgworker.DoWork += new DoWorkEventHandler(FillComboboxBindingList);
m_bgworker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(m_bgworker_RunWorkerCompleted);
BindingList<spIskalnikNaslovi_Result1> m_addresses = new BindingList<SP_Result1>();
void m_bgworker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
int count = (int)((object[])e.Result)[0];
string value = (string)((object[])e.Result)[1];
ComboBox myCombo = (ComboBox)((object[])e.Result)[2];
DelegateUpdateComboboxSelection ndelegate = new DelegateUpdateComboboxSelection(UpdateComboSelection);
if (this.InvokeRequired)
{
Invoke(ndelegate, new object[] {myCombo, value, count});
return;
}
else
{
UpdateComboSelection(myCombo, value, count);
return;
}
}
private void UpdateComboSelection(ComboBox myCombo, String value, int count)
{
myCombo = comboBox9;
myCombo.DataSource = m_addresses;
searchedItem = myCombo.Text;
if (count > 0)
{
myCombo.SelectionStart = value.Length;
myCombo.SelectionLength = searchedItem.Length - value.Length;
myCombo.DroppedDown = true;
}
else
{
myCombo.DroppedDown = false;
myCombo.SelectionStart = value.Length;
}
}
public void FillComboboxBindingList(object sender, DoWorkEventArgs e)
{
if (m_bgworker.CancellationPending)
{
resetWorker.Set();
e.Cancel = true;
return;
}
else
{
string value = (String)((Object[])e.Argument)[0];
List<SP_Result1> result;
result = _vsebina.SP_searcher(value).ToList<SP_Result1>();
m_addresses = new BindingList<SP_Result1>();
foreach (SP_Result1 rez in result)
{
if (m_addresses.Contains(rez))
{
continue;
}
else
{
m_addresses.Add(rez);
}
}
foreach (SP_Result1 r in m_addresses.ToArray())
{
if (!result.Contains(r))
{
m_addresses.Remove(r);
}
}
e.Result = new object[] { rezultat.Count, vrednost, null };
return;
}
}
private void comboBox9_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Back)
{
int searchStart = comboBox9.SelectionStart;
if (searchStart > 0)
{
searchStart--;
if (searchStart == 0)
{
comboBox9.Text = "";
}
else
{
comboBox9.Text = comboBox9.Text.Substring(0, searchStart + 1);
}
}
else
{
searchStart = 0;
}
e.Handled = true;
}
}
private void comboBox9_Enter(object sender, EventArgs e)
{
comboBox9.SelectionStart = 0;
comboBox9.SelectionLength = 0;
}
private void comboBox9_Click(object sender, EventArgs e)
{
comboBox9.Text = "";
}
private void comboBox9_KeyPress(object sender, KeyPressEventArgs e)
{
Search();
}
public void Search()
{
if (comboBox9.Text.Length < 4)
{
return;
}
else
{
if (m_bgworker.IsBusy)
{
m_bgworker.CancelAsync();
m_bgworker = new BackgroundWorker();
m_bgworker.WorkerSupportsCancellation = true;
m_bgworker.DoWork += new DoWorkEventHandler(FillComboboxBindingList);
m_bgworker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(m_bgworker_RunWorkerCompleted);
}
m_bgworker.RunWorkerAsync(new object[] { comboBox9.Text, comboBox9 });
}
}
Maybe can someone enlighten me, what I'm doing wrong. This is first time, that I'm using BackgroundWorker. I have no idea, how
to achieve "search as you type" with combobox in any other way, because my datatable with addresses is quite large (million records).
Thanks in advance for any kind of help or code example.
Vladimir
Edit 1:
Ok, here is my code, before I have used BackGroundWorker. It worked, but it searches very very slow (it can take up to 10 seconds):
private void comboBox9_TextChanged(object sender, EventArgs e)
{
if (comboBox9.Text.Length < 4)
{
return;
}
else
{
FillCombobox(comboBox9.Text, comboBox9);
}
}
public void FillCombobox(string value, ComboBox myCombo)
{
List<spIskalnikNaslovi_Result1> result;
result = _vsebina.spIskalnikNaslovi1(value).ToList();
if (result.Count() > 0)
{
myCombo.DataSource = result;
myCombo.ValueMember = "HS_MID";
myCombo.DisplayMember = "NASLOV1";
var searchedItem = myCombo.Items[0].ToString();
myCombo.SelectionStart = value.Length;
myCombo.SelectionLength = searchedItem.Length - value.Length;
myCombo.DroppedDown = true;
}
else
{
myCombo.DroppedDown = false;
myCombo.SelectionStart = value.Length;
}
return;
}
Is there a way to speed this up without having backgroundworker?

make a button you will call searchbutton
and in click_event of this button call your search() method that run your backgroundworker
that fill the combobox
clear you key_press event of your combobox and it will work
the mistake is you key_press event that call every key stroke happening your search method
so retrieve it

You should get your items in a list, use that list to populate your combobox.
then set AutoCompleteMode property value to Suggest or Append or SuggestAppend and set AutoCompleteSoucre property value to ListItems.

For "Search as you Type", which is actually "Filter as you Type" more than search, you need to implement the OnKeyDown or KeyPressed event.
What you would do is take the search string, which is the current text at the time of the event, then filter the master list using that string. Normally one would use "Starts With" for the filtering, but you could also simply use "Contains". Then you live update the contents of the box with the results from the filter. This is accomplished by changing and refreshing the Datasource.

Here is my final solution without BackGroundWorker. It works quick with my large table, and is upgraded for using a stored procedure on SQL Server (if you use Entity Framework). I use Timer to make sure the user can find a value, that he is searching.
Here you can see the original solution, that I found on this site (thanks to Max Lambertini and algreat for the idea and working concept):
C# winforms combobox dynamic autocomplete
My solution:
private bool _canUpdate = true;
private bool _needUpdate = false;
List<spIskalnikNaslovi_Result1> dataFound;
private void comboBox12_TextChanged(object sender, EventArgs e)
{
if (_needUpdate)
{
if (_canUpdate)
{
_canUpdate = false;
refreshData();
}
else
{
restartTimer();
}
}
}
private void comboBox12_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Back)
{
int searchStart = comboBox12.SelectionStart;
if (searchStart > 0)
{
searchStart--;
if (searchStart == 0)
{
comboBox12.Text = "";
}
else
{
comboBox12.Text = comboBox12.Text.Substring(0, searchStart + 1);
}
}
else
{
searchStart = 0;
}
e.Handled = true;
}
}
private void comboBox12_TextUpdate(object sender, EventArgs e)
{
_needUpdate = true;
}
private void timer1_Tick(object sender, EventArgs e)
{
_canUpdate = true;
timer1.Stop();
refreshData();
}
private void refreshData()
{
if (comboBox12.Text.Length > 1)
{
FillCombobox(comboBox12.Text, comboBox12);
}
}
private void restartTimer()
{
timer1.Stop();
_canUpdate = false;
timer1.Start();
}
private void FillCombobox(string value, ComboBox myCombo)
{
dataFound = _vsebina.spIskalnikNaslovi1(value).ToList();
if (dataFound.Count() > 0)
{
myCombo.DataSource = dataFound;
myCombo.ValueMember = "HS_MID";
myCombo.DisplayMember = "NASLOV1";
var searchedItem = myCombo.Items[0].ToString();
myCombo.SelectionStart = value.Length;
myCombo.SelectionLength = searchedItem.Length - value.Length;
myCombo.DroppedDown = true;
return;
}
else
{
myCombo.DroppedDown = false;
myCombo.SelectionStart = value.Length;
return;
}
}

how to make row flash every 3 seconds

I dont know if I'm doing this correctly but I have a grid and I loop through the grid to see if the items matched. If they do I want to make the row flash every 3 seconds. Right now what I have in my code just pretty much highlight the row but no flashing. Can anyone help take a look?
public static void CheckRow(int item, DataGridViewRow row)
{
List<int> col = new List<int>();
//call to db and add to col
foreach (var item in col)
{
if (item == col.Item)
{
currentRow = row;
Timer t = new Timer();
t.Interval = 3000;
t.Tick += new System.EventHandler(Highlight);
t.Start();
}
}
}
private static void Highlight(object sender, EventArgs e)
{
currentRow.DefaultCellStyle.BackColor = Color.Brown;
}

Wouldn't you need to change the color again (to the original) to have a flashing effect?

You should use Threading. Look at the code :)
bool go = false; //for changing cell color
int count = 10; //to stop timer (blinking)
public blinkForm()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
timer1.Start();
Thread a = new Thread(blink);
a.Start();
}
private void Form1_Load(object sender, EventArgs e)
{
dataGridView1.AutoGenerateColumns = false;
if (dataGridView1.Columns.Count == 0)
{
//generate new columns for DataGridView
dataGridView1.Columns.Add("user", "User");
dataGridView1.Columns.Add("pcStatus", "PC Status");
dataGridView1.Columns.Add("service", "Servis");
//generate new rows for DataGridView
dataGridView1.Rows.Add("Ali", "PC007", "chrome.exe");
dataGridView1.Rows.Add("Vusal", "PC010", "photoshop.exe");
dataGridView1.Rows.Add("Rahim", "PC015", "chrome.exe");
}
}
private void blink(object o)
{
while (count > 0)
{
while (!go)
{
//change color for binking
dataGridView1.Rows[0].Cells["service"].Style.BackColor = Color.Tomato;
go = true;
//stop for 0.5 second
Thread.Sleep(500);
}
while (go)
{
//change color for binking
dataGridView1.Rows[0].Cells["service"].Style.BackColor = Color.LimeGreen;
go = false;
//stop for 0.5 second
Thread.Sleep(500);
}
}
}
private void timer1_Tick(object sender, EventArgs e)
{
count--;
if (count == 0)
{
//stop blinking after 10 second
timer1.Stop();
}
}

Perhaps this, no?
private static void Highlight(object sender, EventArgs e)
{
currentRow.DefaultCellStyle.BackColor = Color.Brown;
System.Threading.Thread.Sleep(2000);
currentRow.DefaultCellStyle.BackColor = Color.White;
}