Hey all i am trying to figure out why my 2nd form is not displaying the value i recived in my first form.
The code for the first form is:
Private Sub scannerOnCom_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
responceBack = scannerOnCom.ReadLine
Call frm1110.clickButton(responceBack)
End Sub
The second form code is this:
Public Sub clickButton(ByRef theResponse As String)
txtNumber.Text = theResponse
'Call cmdNextFinish_Click(Nothing, Nothing)
End Sub
However, when i debug it to make sure there is something stored for theResponse, there is but for some reason it does not put it into the textbox. It's blank.
Any help would be great!
David
UPDATE
Ok so Form1:
Dim tmpForm3020 As New frm3020
Private Sub cmd3020_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmd3020.Click
tmpForm3020.Show()
Me.WindowState = FormWindowState.Minimized
End Sub
Private Sub scannerOnCom_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
responceBack = scannerOnCom.ReadLine
tmpForm3020.txtNumber.Text = responceBack
End Sub
If thats correct then i get an error on line:
xForm.txtNumber.Text = responceBack
Saying:
Cross-thread operation not valid: Control 'txtNumber' accessed from a thread other than the thread it was created on.
Are you explicitly creating an instance of your second form, or relying on the default instance? I.e. is "frm1110" the second form's class name, or an instance that you have new'd up? Make sure in either case that it is the same instance that is actually being displayed.
Dim tmpForm3020 As New frm3020
Private Sub cmd3020_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmd3020.Click
tmpForm3020.Show()
Me.WindowState = FormWindowState.Minimized
End Sub
Private Sub scannerOnCom_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
responceBack = scannerOnCom.ReadLine
TestData(responceBack)
End Sub
Private Sub TestData(ByVal xVal As String)
If InvokeRequired Then
Me.Invoke(New MethodInvoker(AddressOf TestData))
' change Me to tmpForm3020 (if it does not work)
' tmpForm3020.Invoke(New MethodInvoker(AddressOf TestData))
Else
tmpForm3020.txtNumber.Text = xVal
End If
End Sub
Related
I am a beginner and please show me how to pass the parameter object Person to Button.Click event. I'm using vb.net. Here is my code:
Public Class Form1
Public Class MyPersonClass
Public Name As String
Public Age As Integer
Public Title As String
End Class
Public Sub DisplayPerson(ByVal person As MyPersonClass)
Label1.Text = person.Name
Label2.Text = person.Age.ToString()
Label3.Text = person.Title
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
End Sub
End Class
You don’t – Button1_Click is an event handler, you’re not supposed to call it manually. It gets called, with predefined parameters, when a certain event occurs. You cannot really adapt these parameters, simply because it doesn’t make sense: the event would no longer know how to call the handler.
You can easily write your own method and pass any object to it, of course. And you’ve done exactly that with DisplayPerson.
Private ExamplePerson As MyPerson
Private Sub Form_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
ExamplePerson = New MyPersonClass 'thanks Chris Dunaway for the correction
ExamplePerson.Name = "Test Name"
ExamplePerson.Age = 36
ExamplePerson.Title = "Title Name"
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
DisplayPerson(ExamplePerson)
End Sub
I am trying to call a thread on a button click event. i dont fell my code is not making any syntax error. but its not working.
Private Sub btnHisStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnHisStart.Click
thrHis = New Thread(AddressOf threadHistorical)
thrHis.Start()
End Sub
Private Sub threadHistorical()
'code
End Sub
Add this line and check it
System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = False
I am trying to pass a value of a textbox on frmMain to a textbox on frmDepartment. I have tried the following code which I thought would work but it dosen't. I ma a new user to VB and come from a php background where it would have been a simple task of setting a seesion. Can anyone help with this? If you need to see more code, please ask. many thanks
txtDeptCustomer.Text = frmMain.txtCustomerActive.Text
In frmMain, I am getting value like this:
Dim value As Object = UserDataGridView.Rows(e.RowIndex).Cells(0).Value
txtCustomerActive.Text = CType(value, String)
Private Sub btnDepts_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDepts.Click
frmDepartment.Show()
End Sub
Which is showing in frmMain ok.
In frmDepartment I have this code
Private Sub txtDeptCustomer_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtDeptCustomer.TextChanged
'Dim customer As String
txtDeptCustomer.Text = frmMain.txtCustomerActive.Text
End Sub
instead of putting the code within the txtDeptCustomer.TextChanged sub, try putting it within the frmDepartment_load:
Private Sub frmDepartment_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
txtDeptCustomer.Text = frmMain.txtCustomerActive.Text
End Sub
or you could set the frmDepartment text box text on the frmMain button click:
Private Sub btnDepts_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDepts.Click
frmDepartment.txtDeptCustomer.Text = txtCustomerActive.Text
frmDepartment.Show()
End Sub
A few weeks ago I wrote a wrapper for the ServiceController control to enhance and streamline the base ServiceController. One of the changes I made was to add a monitoring component using the System.Threading.Timer object. On any change of status, an event is raised to the parent class. The actual monitoring works fine, but when the event is handled in the main form, my program abruptly ends - no exceptions, no warning, it just quits. Here's a skeleton version of the control:
Public Class EnhancedServiceController
Inherits ServiceController
Public Event Stopped(ByVal sender As Object, ByVal e As System.EventArgs)
Public Event Started(ByVal sender As Object, ByVal e As System.EventArgs)
Private _LastStatus As System.ServiceProcess.ServiceControllerStatus
Private serviceCheckTimer as System.Threading.Timer
Private serviceCheckTimerDelegate as System.Threading.TimerCallback
...
Private Sub StartMonitor()
MyBase.Refresh()
_LastStatus = MyBase.Status
serviceCheckTimerDelegate = New System.Threading.TimerCallback(AddressOf CheckStatus)
serviceCheckTimer = New System.Threading.Timer(serviceCheckTimerDelegate, Nothing, 0, 60*1000)
End Sub
Private Sub CheckStatus()
MyBase.Refresh()
Dim s As Integer = MyBase.Status
Select Case s
Case ServiceControllerStatus.Stopped
If Not s = _LastStatus Then
RaiseEvent Stopped(Me, New System.EventArgs)
End If
Case ServiceControllerStatus.Running
If Not s = _LastStatus Then
RaiseEvent Started(Me, New System.EventArgs)
End If
End Select
_LastStatus = s
End Sub
End Class
And the form:
Public Class Form1
Private Sub ServiceStarted(ByVal sender As Object, ByVal e As System.EventArgs) Handles ESC.Started
Me.TextBox1.Text = "STARTED"
End Sub
Private Sub ServiceStopped(ByVal sender As Object, ByVal e As System.EventArgs) Handles ESC.Stopped
Me.TextBox1.Text = "STOPPED"
End Sub
End Class
If I had to guess, I'd say that there's some sort of thread problem, but I'm not sure how to handle that in the form. Any ideas?
IF it is a threading issue then you are probably trying to update the UI from a non-UI thread.
So something like this should solve that...
Private Delegate Sub UpdateTextBoxDelegate(byval tText as String)
Private Sub UpdateTextBox(byval tText As String)
If Me.InvokeRequired Then
Me.Invoke(New UpdateTextBoxDelegate(AddressOf UpdateTextBox), tText)
Exit Sub
End If
TextBox1.Text = tText
End Sub
Private Sub ServiceStarted(ByVal sender As Object, ByVal e As System.EventArgs) Handles ESC.Started
UpdateTextBox ("STARTED")
End Sub
Private Sub ServiceStopped(ByVal sender As Object, ByVal e As System.EventArgs) Handles ESC.Stopped
UpdateTextBox("STOPPED")
End Sub
I have, what should be , a very simple problem, but now I have used 5 hours without results.
I have a usercontrol, UserControl1, which I want to drag and drop on my form, Form1.
That’s it. It should be simple, but I have googled for hours without results. Does anybody have a sample code to fix this?
I dont know what a user control is (I'm still learning) but I found something that might help.
In this code, add two TextBox controls to a form and set the AllowDrop property of the second TextBox control to True.
Then use this code to enable drag and drop
Private MouseIsDown As Boolean = False
Private Sub TextBox1_MouseDown(ByVal sender As Object, ByVal e As _
System.Windows.Forms.MouseEventArgs) Handles TextBox1.MouseDown
' Set a flag to show that the mouse is down.
MouseIsDown = True
End Sub
Private Sub TextBox1_MouseMove(ByVal sender As Object, ByVal e As _
System.Windows.Forms.MouseEventArgs) Handles TextBox1.MouseMove
If MouseIsDown Then
' Initiate dragging.
TextBox1.DoDragDrop(TextBox1.Text, DragDropEffects.Copy)
End If
MouseIsDown = False
End Sub
Private Sub TextBox2_DragEnter(ByVal sender As Object, ByVal e As _
System.Windows.Forms.DragEventArgs) Handles TextBox2.DragEnter
' Check the format of the data being dropped.
If (e.Data.GetDataPresent(DataFormats.Text)) Then
' Display the copy cursor.
e.Effect = DragDropEffects.Copy
Else
' Display the no-drop cursor.
e.Effect = DragDropEffects.None
End If
End Sub
Private Sub TextBox2_DragDrop(ByVal sender As Object, ByVal e As _
System.Windows.Forms.DragEventArgs) Handles TextBox2.DragDrop
' Paste the text.
TextBox2.Text = e.Data.GetData(DataFormats.Text)
End Sub
I hope that you can use this for a usercontrol. Good luck and comment!
Here is the code, I have used, to get it work.
Now I have a form, Form1, and a usercontrol, Usercontrol1. To drag the usercontrol, I inserted a panel in the top of the usercontrol, and only if the user pressed the panel (panel1), the control should to move - like normal windows forms.
Public Class UserControl1
Shared mypositionX As Integer
Shared mypositionY As Integer
Shared mBlnFormDragging As Boolean
Shared drawBeginX As Integer
Shared drawBeginY As Integer
Shared drawing As Boolean
Private Sub Panel1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseMove
If mBlnFormDragging = True Then
Dim position As Point = Form1.PointToClient(MousePosition)
Me.Location = New Point(position)
End If
End Sub
Private Sub Panel1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseUp
' Dim dd1 As DragDropEffects = DoDragDrop(ParentForm, DragDropEffects.Move)
mBlnFormDragging = False
Dim position As Point = Form1.PointToClient(MousePosition)
Location = New Point(position)
End Sub
Public Sub Panel1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseDown
'Dim dd1 As DragDropEffects = DoDragDrop(ParentForm, DragDropEffects.Move)
mBlnFormDragging = True
End Sub