In my application i have a label that displays the current time in HH:mm:ss
How can i get the label to update its content each second so that the time actually is correct?
Add a Timer to your project. Set the Interval property to 1000. Then...
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Timer1.Enabled = True
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Label1.Text = 'Your code
End Sub
Related
I am trying to create a program which:
Downloads a web page on a regular interval (every 10 minutes)
Finds a specific element on the page (an HTML div element with an ID of rekto)
Checks the value of that element, and then acts on it (if it's 0, do nothing and wait for the next cycle, and it if it's 1, launch notepad.exe)
Here's the code I have so far:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
WebBrowser1.Navigate("https://controlry.tr.gg/control.htm")
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
'Me.Hide()
Timer1.Enabled = False
WebBrowser1.Refresh()
WebBrowser1.Document.GetElementById("rekto").GetAttribute("value")
If
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Enabled = True
End Sub
I have two forms in my application, form2 is shown on clicking a button in the form1. but i need a delay of 7 seconds between form1's close and form2's show for that i wrote the following code:
Public Class Form1
Dim i As Integer
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
i = 0
Me.Close()
Timer1.Enabled = True
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
i += 1
If i = 7 Then
Form1.Show()
End If
End Sub
End Class
But it does not give me the result. form2 not shown at all. what was the mistake i had made in the code? can anyone help me?
Thanks in advance.
When there's no active form left in a Windows Forms application, the application will quit. Therefore, you might want to hide the main form instead of closing it:
Me.Hide()
i think no need of unnecessary declaration for time delay because you can simply set it on your timer control itself
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Interval = 7000
Timer1.Start()
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Form2.Show()
Me.Close()
End Sub
End Class
or
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Interval = 7000
Timer1.Start()
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Me.Close()
End Sub
Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
Form2.Show()
End Sub
My goal is to make code that will beep randomly anywhere from 1 to 30 seconds apart. Here is my code so far:
Public Class Form1
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Console.Beep()
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Timer1.Stop()
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Start()
End Sub
End Class
This beeps every one second. Now, I want to change the Timer Interval so that it will beep randomly between 1 and 30 seconds. Maybe later I will add options for the user to define the bounds, but for now, 1 and 30 are good numbers. I just don't know how to apply a random number to my Timer Interval.
Change the Interval on every Tick:
Public Class Form1
Private p_oRandom As Random
Private Const INTERVAL_MIN_SEC As Integer = 1
Private Const INTERVAL_MAX_SEC As Integer = 30
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
p_oRandom = New Random
End Sub
Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As EventArgs) Handles _
Timer1.Tick
Console.Beep()
Timer1.Interval = p_oRandom.Next(INTERVAL_MIN_SEC, INTERVAL_MAX_SEC) * 1000
End Sub
End Class
I'm trying to view youtube captcha in my vb application but I don't know how to refresh/redraw the picture box. The youtube captcha is in http://www.youtube.com/cimg and the captcha is changing everytime I refresh the page. How can I do that using button or timer in vb.net to change the captcha. Here is the code I used to load the captcha to picturebox.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
captchaBox.ImageLocation = "http://www.youtube.com/cimg"
End Sub
i try to use captchaBox.Refresh() but it's not working. I hope someone can help me. thx
Refresh just redraws the control, it doesn't retrieve the image again. You need to reset the ImageLocation property for it to work. For example with a timer:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
captchaBox.ImageLocation = "http://www.youtube.com/cimg"
Timer1.Enabled = True
Timer1.Interval = 1000
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
captchaBox.ImageLocation = "http://www.youtube.com/cimg"
End Sub
Try this:
Private Sub Form1_Load() Handles MyBase.Load
Timer1.Start()
PictureBox1.ImageLocation = "http://www.youtube.com/cimg"
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
PictureBox1.Image = Nothing
PictureBox1.ImageLocation = "http://www.youtube.com/cimg"
End Sub
I have a case where i need to generate millions of unique codes. For this I have created a generate function where the random number is generated. I call this function from a for loop and add the generated number on a list box. my code is as follow
for i=1 to val(txtnumber.txt)
mynum=generate()
next
I have created a lable on form where i wanted to display the no of secs elapsed while processing the loop. I used timer control as
timer1.start()
for i=1 to val(txtnumber.text)
mynum=generate()
listbox1.items.add(mynum)
next
timer1.stop
and on timer1_tick function
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Label1.Text = Val(Label1.Text) + 1
End Sub
but when i click generate button, all numbers are generated, but timer doesnot shows time elapsed.
I may have missed something, so please help me out
This is probably best handled in a BackgroundWorker. Place one on the form and set its WorkerReportsProgress=True. Also, placing a million numbers in a ListBox probably isn't a good idea, so I omitted that.
Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
Button1.Enabled = False
BackgroundWorker1.RunWorkerAsync()
End Sub
Private Sub BackgroundWorker1_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim started As DateTime = Now
For i As Integer = 1 To val(txtnumber.txt)
mynum=generate()
BackgroundWorker1.ReportProgress(i, Nothing)
Next
Dim ended As TimeSpan = Now.Subtract(started)
BackgroundWorker1.ReportProgress(0, ended.TotalSeconds.ToString)
End Sub
Private Sub BackgroundWorker1_ProgressChanged(ByVal sender As Object, ByVal e As ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
If e.UserState IsNot Nothing Then
Label1.Text = e.UserState.ToString()
Else
Label1.Text = e.ProgressPercentage.ToString
End If
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
Button1.Enabled = True
End Sub
Your label should be updating correctly when the worker reports the ProgressChanged event.
What you're encountering is a threading issue. The work you are doing to generate the numbers is being executing by the UI thread, so it never gets a chance to update the screen. Take a look here: How to prevent UI from freezing during lengthy process?
This one might also have good information for you: Updating UI from another thread
Try this:
Private _Counter As Integer = 0
Private _StartTime As Date = Now
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
_StartTime = Now
_Counter = CInt(Val(txtnumber.Text))
ListBox1.Items.Clear()
Label1.Text = "0"
Timer1.Interval = 50
Timer1.Start()
End Sub
Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
ListBox1.Items.Add(generate())
Label1.Text = New Date((Now - _StartTime).Ticks).ToString("HH:mm:ss.ff")
_Counter -= 1
If (_Counter <= 0) Then
Timer1.Stop()
End If
End Sub
Or you can research actual Threading.