How to create make an event call back every x seconds in VB.NET?
How do I make it add one to my counter every 10 seconds?
Public Class Form1
Private Counter As Integer = 0
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Label1.Text = Counter.ToString
Me.Timer1.Interval = TimeSpan.FromSeconds(10).TotalMilliseconds
Me.Timer1.Start()
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Counter = Counter + 1
Label1.Text = Counter.ToString
End Sub
End Class
Related
I'm using the following code to control a label to output a stopwatch. The buttons work, and the label is outputting the information mostly correctly, however it only update every so often and i would like for the label to update the information every millisecond.
Private SW As New Stopwatch
Dim timercount As Integer = 1 'The number of seconds
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
SW.Start()
Timer1.Start()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Timer1.Enabled = False 'Stop the timer
timercount = 0 'Reset to 0 seconds
Label10.Text = "00:00:00.000"
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Dim ts As TimeSpan = SW.Elapsed
Label10.Text = ts.ToString("hh\:mm\:ss\.fff")
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
Timer1.enabled = False
End Sub
Any help is much appreciated.
You can set the timer to a reasonable value, say 20 times a second, to rapidly display it changing.
You can create the timer and stopwatch in code, which I think is easier than adding a control to the form—you can see right there in the code what is being programmed. I used sensible names for the buttons so that you can tell what is meant to do what.
If you keep the sub to display the data separate from the code that processes the data, it is easy to change the display in just one place, in case someone decided they wanted it written as words, for example, or maybe the hours in a separate box, or something.
Public Class Form1
Dim sw As New Stopwatch
Dim tim As Timer
Private Sub ShowElapsedTime()
lblTime.Text = sw.Elapsed.ToString("hh\:mm\:ss\.fff")
End Sub
Private Sub bnStart_Click(sender As Object, e As EventArgs) Handles bnStart.Click
sw.Restart()
tim.Enabled = True
End Sub
Private Sub bnStop_Click(sender As Object, e As EventArgs) Handles bnStop.Click
sw.Stop()
tim.Enabled = False
ShowElapsedTime()
End Sub
Private Sub bnReset_Click(sender As Object, e As EventArgs) Handles bnReset.Click
tim.Enabled = False
sw.Reset()
ShowElapsedTime()
End Sub
Private Sub tim_Tick(sender As Object, e As EventArgs)
ShowElapsedTime()
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
tim = New Timer With {.Interval = 50}
AddHandler tim.Tick, AddressOf tim_Tick
ShowElapsedTime()
End Sub
End Class
so I want to display a string array in a single label that change the contents with a period of time ,
I ve tried every thing the timer, the background worker every thing , the problem when I use a loop inset a timer the interval in the start should be so long if the array items was so many so I tried the background worker but it not works
this is the code :
Dim array() As String = {"so", "nb", "de", "rty", "dcds"}
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
BackgroundWorker1.RunWorkerAsync()
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Control.CheckForIllegalCrossThreadCalls = False
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim worker As BackgroundWorker = CType(sender, BackgroundWorker)
Dim delay As Integer = 2000
Dim interval As Integer = 100
Dim elapsed As Integer = 0
Dim pos As Integer = array.Length
While Not worker.CancellationPending
If (elapsed >= delay) Then
worker.ReportProgress(pos)
' change label text in the Progress event handler
pos = (pos + 1)
elapsed = 0
If (pos = array.Length) Then
Exit While
End If
End If
Thread.Sleep(interval)
End While
End Sub
Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Dim j As Integer
For j = 0 To array.Length
Label1.Text = array(j)
Next
End Sub
Your for loop is overwriting the .Text property of the lable on each iteration. You will also get an Index Out of Range exception because the indexes of an array are zero based. The highest index will be 1 less than the .Length.
Private arStr() As String = {"so", "nb", "de", "rty", "dcds"}
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim LabelText = String.Join(Environment.NewLine, arStr)
Label1.Text = LabelText
End Sub
EDIT
Private arStr() As String = {"so", "nb", "de", "rty", "dcds"}
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Static index As Integer
If index < arStr.Length Then
Label1.Text &= arStr(index) & Environment.NewLine
index += 1
End If
End Sub
With asynchronous approach you can display array values one after another without BackgroundWorker and explicitly created Timer.
Private _values As New String() From {"so", "nb", "de", "rty", "dcds"}
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
For Each value In _values
await Task.Delay(2000)
Next
End Sub
With asynchronous approach you can prevent button click before all values are displayed in the simple way as you would do in synchronous code.
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim button = DirectCast(sender, Button);
button.Enabled = False
For Each value In _values
await Task.Delay(2000)
Next
button.Enabled = True
End Sub
I am using for, while & do while loop in vb.net to add some values in list box. I want to use a timer to delay in adding values to list box. Please tell the syntax, what should I use & Following is my code:
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Integer
For a = 1 To 10
ListBox1.Items.Add(a)
End If
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim b As Integer
b = 4
If b < 5 Then
MessageBox.Show("eRROR")
End If
While b <= 3
ListBox2.Items.Add(b)
b = b + 1
End While
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim c As Integer
c = 20
Do
c = c + 1
ListBox3.Items.Add(c)
Loop While c <= 30
End Sub
Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
End Class
A timer executes once every n milliseconds, you take advantage of this by handling the timer's Tick event. If you wanted to keep track of what increment you're on, either declare a private variable outside of the scope (see here) of the Tick event or declare a static variable inside the Tick event.
Private Variable:
Private counter As Integer = 0
Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As EventArgs) Handles Timer1.Tick
counter += 1
If (counter < 31) Then
ListBox1.Items.Add(counter)
Else
Timer1.Stop()
End If
End Sub
Static Variable:
Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As EventArgs) Handles Timer1.Tick
Static counter As Integer = 0
If (counter < 31) Then
counter += 1
ListBox1.Items.Add(counter)
Else
Timer1.Stop()
End If
End Sub
I setup a counter which needs to be enabled at specific time everyday. for an example lets say at (3 PM) everyday. what i came up with is following piece of code. but it gives me an error when it reach the time saying parameter is not valid please help me,
Private t As Integer = 0
Private Sub Home_monitoring_tab_Load(sender As Object, e As EventArgs) Handles MyBase.Load
rs.FindAllControls(Me)
Execute()
End Sub
Private Sub Execute()
If DateTime.Now.ToString("HH:mm") = "15:00" Then
shift1_timer.Enabled = True
End If
End Sub
Private Sub shift1_timer_Tick(sender As Object, e As EventArgs) Handles shift1_timer.Tick
t += 1
Label14.Text = CStr(t)
End Sub
Try this, add a timer to your program and call it CheckTimer and update your code like this :
Private t As Integer = 0
Private Sub Home_monitoring_tab_Load(sender As Object, e As EventArgs) Handles MyBase.Load
rs.FindAllControls(Me)
CheckTimer.Interval = 1
CheckTimer.Start
End Sub
Private Sub CheckTimer_Tick(sender As Object, e As EventArgs) Handles CheckTimer.Tick
If DateTime.Now.ToString("HH:mm") = "15:00" Then
shift1_timer.Enabled = True
End If
End Sub
Private Sub shift1_timer_Tick(sender As Object, e As EventArgs) Handles shift1_timer.Tick
t += 1
Label14.Text = CStr(t)
End Sub
Hope it helped :)
I have a loop that runs but would like it to stop on the press of a button and start again when another is pressed. This is my code:
Public Class Form1
Private loopon As Boolean
Public Function ping(ByVal server As String) As String
Dim s As New Stopwatch
s.Start()
My.Computer.Network.Ping(server)
s.Stop()
Return s.ElapsedMilliseconds.ToString
End Function
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
loopon = True
TextBox1.Text = "Ping results:"
Do While loopon = True
TextBox1.AppendText(Environment.NewLine)
TextBox1.AppendText(ping("server name here"))
Loop
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
loopon = False
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = String.Empty
TextBox1.Text = "Ping results:"
loopon = True
End Sub
End Class
When I try to run the code, with debugging, my computer gives me a blue screen after a while and restarts. I'm pretty sure I messed up with the exiting of the loop. Any suggestions?
You could use a Timer to ping (say) every 5 seconds until the "Stop" button is clicked. In the Form Designer, drag a Timer onto the form, and use this code:
Public Class Form1
Private stopPing As Boolean
Public Sub Ping(ByVal server As String)
Dim s As New Stopwatch
s.Start()
My.Computer.Network.Ping(server)
s.Stop()
TextBox1.AppendText(Environment.NewLine & s.ElapsedMilliseconds.ToString)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = "Ping results:"
Ping "server name here"
Timer1.Interval = 5000 'Set timer Interval to 5 seconds
Timer1.Start
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
stopPing = True
End Sub
Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
If stopPing Then Timer1.Stop Else Ping "server name here"
End Sub
End Class