I want to block the key board input when the form starts, but it is not working, please check my code:
Public Class Form2
Public Declare Function BlockInput Lib "User32" (ByVal fBlock As Integer) As Integer
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Sub Panel1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Panel1.Paint
End Sub
Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
Dim name As String
name = "12345"
If (name = TextBox1.Text) Then
Me.Close()
End If
End Sub
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Visible = True
TextBox1.Focus()
End Sub
Private Sub TextBox2_Click_1(ByVal sender As Object, ByVal e As EventArgs) Handles TextBox2.MouseClick
BlockInput(1)
End Sub
Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
End Sub
End Class`
I used "groupbox.enabled = False" in order to stop program users from editing anything within the groupbox on my form. You can then enable the groupbox again providing certain conditions are met. Another method I've used in my programming for VB.net was setting the read-only property (I used to to auto-populate the system date to prevent users from entering false dates) I don't know if either of those methods might help you?
Related
I'm facing a big problem here, I'm developing a app to read data from a Weight.
Everything is working perfectly, but the result is not what I expected: when reading the data from the scale, it keeps printing the data without stopping and I would like it to read a single line and whenever there is any change in the scale, just change the value and not add a new line...
The way it's printed:
My code:
Public Class Form1
Dim Q As Queue(Of String) = New Queue(Of String)
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
For Each s In System.IO.Ports.SerialPort.GetPortNames()
ComboBox1.Items.Add(s)
Next s
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
If ComboBox1.SelectedIndex = -1 Then
MsgBox("Please select a port")
Exit Sub
Else
SerialPort1.BaudRate = 9600
SerialPort1.DataBits = 8
SerialPort1.Parity = IO.Ports.Parity.None
SerialPort1.StopBits = IO.Ports.StopBits.One
SerialPort1.PortName = ComboBox1.SelectedItem.ToString
SerialPort1.Open()
Timer1.Start()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, _
ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) _
Handles SerialPort1.DataReceived
Q.Enqueue(SerialPort1.ReadExisting())
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Timer1.Tick
SyncLock Q
While Q.Count > 0
TextBox1.Text &= Q.Dequeue
End While
End SyncLock
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
SerialPort1.Close()
Timer1.Stop()
End Sub
End Class
Here's a simple example using Control.BeginInvoke() to set a Control's property with some data coming from a secondary Thread.
You can use this method since you have all your code in a Form and you use
a SerialPort Component.
Otherwise, build a class to handle the SerialPort and pass a delegate to its Constructor, capture SynchronizationContext.Current and Post() to the delegate.
Or use an IProgress<T> delegate (Progress(Of String) here) and pass this delegate to the class, then just call its Report() method from the event handler.
Assuming ReadExisting() works for you and the Encoding is set correctly (it appears to be, from the results shown in the OP), you could change the code in the DataReceived handler to:
It's required to check whether the handles of the Controls involved (the Form, mainly) are created before calling Invoke() / BeginInvoke(), otherwise you may (will, at some point) get an exception that may kill the application (the IProgress<T> pattern is preferable).
Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Dim comPort = DirectCast(sender, SerialPort)
UpdateUI(comPort.ReadExisting())
End Sub
' [...]
Private lastWeight As String = String.Empty
Private Sub UpdateUI(weight As String)
If IsHandleCreated Then
BeginInvoke(New Action(
Sub()
If Not lastWeight.Equals(weight) Then
lastWeight = weight
If TextBox1.IsHandleCreated Then TextBox1.Text = lastWeight
End If
End Sub))
End If
End Sub
Make a test with a threaded Timer, setting the Interval to a low value (e.g., 50ms).
You can also try to close the Form without stopping the Timer.
Found the soluction:
Public Class Form5
Delegate Sub SetTextCallback(ByVal data As String)
Private Delegate Sub UpdateLabelDelegate(theText As String)
Private Sub UpdateLabel(theText As String)
If Me.InvokeRequired Then
Me.Invoke(New UpdateLabelDelegate(AddressOf UpdateLabel), theText)
Else
TextBox1.Text = theText
End If
End Sub
Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Dim returnStr As String
returnStr = SerialPort1.ReadExisting
Me.BeginInvoke(Sub()
UpdateLabel(returnStr)
End Sub)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
SerialPort1.Open()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
SerialPort1.Close()
End Sub
End Class
How can i make this code to loop urls continuously in Webbrowser1, after run trough these links one time.
This is the code i have so far, but when i run this, the Webbrowser stop with last url, wich is google.com. What i want to do is when the last url is reached i want it to start from top again, and run trough links again and again, until i exit the program.
Public Class Form1
Private WithEvents backgroundWorker1 As System.ComponentModel.BackgroundWorker
Dim l As New List(Of String)
Dim flagDC As Boolean = False
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Button1.Hide()
Button3.Show()
l = New List(Of String)
l.Add("http://bbc.com/sipeu/php/zq.php")
l.Add("http://google.com")
l.Add("http://DCWC.com/sipeu/us.php")
l.Add("http://google.com")
l.Add("http://example.com/sipeu/v.php")
l.Add("http://google.com")
backgroundWorker1 = New System.ComponentModel.BackgroundWorker
backgroundWorker1.RunWorkerAsync()
End Sub
Private Sub BackgroundWorker2_DoWork(ByVal sender As System.Object,
ByVal e As System.ComponentModel.DoWorkEventArgs) _
Handles backgroundWorker1.DoWork
For Each www In l
flagDC = False
WebBrowser1.Navigate(www)
Do
Loop While Not flagDC
Next
End Sub
Private Sub WebBrowser1_DocumentCompleted(ByVal sender As System.Object,
ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) _
Handles WebBrowser1.DocumentCompleted
System.Threading.Thread.Sleep(1000)
flagDC = True
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Button3.Hide()
ChangeUserAgent("troll001_v2-agent34")
WebBrowser1.Navigate("http://example.com/welcome.php")
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Close()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs)
End Sub
i am getting really annoyed by this piece of code for visual basic
please can you help. i have looked on YouTube and everywhere else even the vb website!!! i would really appreciate it if someone could help me out
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
MessageBox.Show("Hi!!")
Timer1.Start()
End Sub
Private Sub ProgressBar1_Click(sender As Object, e As EventArgs) Handles ProgressBar1.Click
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
ProgressBar1.Increment(1)
If ProgressBar1.Value = 100 Then
Timer1.Stop()
MsgBox("Jeff")
End If
End Sub
Private Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs)
End Sub
Private Function GetNumericUpDown1(v As Integer) As Boolean
End Function
Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
If ( : ( ) Then
MessageBox.Show("Well Done!")
End If
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
MessageBox.Show("!!Stopped!!")
Timer2.Stop()
End Sub
Private Sub Timer2_Tick(sender As Object, e As EventArgs) Handles Timer2.Tick
ProgressBar2.Increment(0.6)
If ProgressBar2.Value = 100 Then
Timer2.Stop()
MsgBox("Jeff")
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
MessageBox.Show("!!Started!!")
Timer2.Start()
End Sub
Private Sub SplitContainer1_Panel1_Paint(sender As Object, e As PaintEventArgs) Handles SplitContainer1.Panel1.Paint
End Sub
Private Sub NotifyIcon1_MouseDoubleClick(sender As Object, e As MouseEventArgs)
End Sub
Private Sub TreeView1_AfterSelect(sender As Object, e As TreeViewEventArgs)
End Sub
Private Sub Timer3_Tick(sender As Object, e As EventArgs) Handles Timer3.Tick
ProgressBar3.Increment(1)
If ProgressBar3.Value = 100 Then
Timer3.Stop()
End If
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
Timer3.Start()
End Sub
Private Sub ProgressBar3_Click(sender As Object, e As EventArgs) Handles ProgressBar3.Click
End Sub
End Class
BTW:this is my first post so it is probably rubbish!!
I don't have enough points to comment.
First off, as others have said we can't recreate this since we have no idea what your Form looks like or what you are expecting it to do.
Secondly, you should turn on Option Strict in the Compile section of Project properties to avoid technical errors like ProgressBar2.Increment(0.6) since 0.6 isn't a valid integer.
I threw together a TabControl (which you never mentioned in the OP) with 3 tabs and the various buttons and progress bars you list in what seemed like a logical fashion to me and it ran just fine for what code you have. Clicked the button on each tab and each progress bar eventually got to 100%. I have no idea what else you were expecting.
If you remove all the empty subs and action listeners, it would be easier to detect the problem
I have two buttons Start button and Stop button .I run my program by clicking on start button. I want to stop the program during the start button . But the program will not responde until the start buttun finish its job. How i can do check the stop buttun during the start. i heard about threading but i do not know how i can do it.
Private Sub Button_Start (ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
//my code
//check always if the user push stop if no continue if yes go to this sub
//my code
end sub
Private Sub Button_Stop (ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
stopClick = True
Dim Response As Integer
Response = MessageBox.Show("Do you really want to exit?", "", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
If Response = vbYes Then
Me.Close()
End If
End Sub
you can use threading put button1 code in a function and use the thread .
you can refer to this example
'Thread created to handle the Background process for start_function
Dim t As System.Threading.Thread
Private Sub start_function()
While True
'your code here for Eg:
Dim i As Integer
i = i + 1
End While
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
t = New System.Threading.Thread(AddressOf Me.start_function)
t.Start()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
t.Abort()
End Sub
Drag a backgroundworker component onto your form.
Imports System.ComponentModel
Public Class Form1
Private Sub btnStart_Click(sender As Object, e As EventArgs) Handles btnStart.Click
Me.Text = "Busy Doing Work"
BackgroundWorker1.WorkerSupportsCancellation = True
BackgroundWorker1.RunWorkerAsync()
End Sub
Private Sub btnStop_Click(sender As Object, e As EventArgs) Handles btnStop.Click
Me.Text = "Asking to Cancel"
BackgroundWorker1.CancelAsync()
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
While Not BackgroundWorker1.CancellationPending
System.Threading.Thread.Sleep(1000)
End While
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
Me.Text = "Cancelled"
End Sub
End Class
I'm looking for a way to detect if the user has been idle for 5 min then do something, and if and when he comes back that thing will stop, for example a timer.
This is what i have tried (but this will only detect if form1 has been inactive / not clicked or anything):
Public Class Form1
Private Sub form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'You should have already set the interval in the designer...
Timer1.Start()
End Sub
Private Sub form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress
Timer1.Stop()
Timer1.Start()
End Sub
Private Sub form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
Timer1.Stop()
Timer1.Start()
End Sub
Private Sub form1_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseClick
Timer1.Stop()
Timer1.Start()
End Sub
Private Sub Timer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
MsgBox("Been idle for to long") 'I just have the program exiting, though you could have it do whatever you want.
End Sub
End Class
This is done easiest by implementing the IMessageFilter interface in your main form. It lets you sniff at input messages before they are dispatched. Restart a timer when you see the user operating the mouse or keyboard.
Drop a timer on the main form and set the Interval property to the timeout. Start with 2000 so you can see it work. Then make the code in your main form look like this:
Public Class Form1
Implements IMessageFilter
Public Sub New()
InitializeComponent()
Application.AddMessageFilter(Me)
Timer1.Enabled = True
End Sub
Public Function PreFilterMessage(ByRef m As Message) As Boolean Implements IMessageFilter.PreFilterMessage
'' Retrigger timer on keyboard and mouse messages
If (m.Msg >= &H100 And m.Msg <= &H109) Or (m.Msg >= &H200 And m.Msg <= &H20E) Then
Timer1.Stop()
Timer1.Start()
End If
End Function
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Timer1.Stop()
MessageBox.Show("Time is up!")
End Sub
End Class
You may have to add code that disables the timer temporarily if you display any modal dialogs that are not implemented in .NET code.
This might work by setting it to just call the Reset idk i just want it work all over the program idk how to do it, i just created this code :
Public Class test
Dim IdleTimer As String
Dim testsave As String
Dim idle_TimerSet As String = 60 '<---- Here You choose The timer (1 per Sec)
Private Sub test_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
IdleTimer = idle_TimerSet
End Sub
Private Sub Idle_Tick(sender As Object, e As EventArgs) Handles Idle.Tick
If IdleTimer <= 1 Then
MsgBox("[ Idle Screen ]")
Else
IdleTimer = IdleTimer - 1 '<--- The Counter
IdleTracker.Text = IdleTimer
End If
End Sub
Private Sub test_MouseDown(sender As Object, e As MouseEventArgs) Handles Me.MouseDown
Call Reset_Idle() 'This is on the main Form
End Sub
Private Sub test_MouseMove(sender As Object, e As MouseEventArgs) Handles Me.MouseMove
Call Reset_Idle() 'This is on the main Form
End Sub
Public Sub Reset_Idle() '<-- The Reset Action
'Idle.Enabled = False
IdleTimer = idle_TimerSet
'Idle.Enabled = True
End Sub
End Class