I am a newbie, but I am unable to get this code working. FileSweeper is supposed to start a timmer that triggers fileCopy on a web server. fileSweeoer is triggered by global.asax. FileCopy then will copy the file. However the FC.copy never fires. Any help/explanation would be helpful!
Would it make any difference if this was a class running on a web server?
My code is from http://msdn.microsoft.com/en-us/library/system.threading.timer.aspx.
Imports Microsoft.VisualBasic
Imports System
Imports System.Threading
Public Class fileSweeper
Dim stateTimer As Timer
<MTAThread()> _
Sub Main()
Dim FC As New fileCopy
Dim tcb As TimerCallback = AddressOf FC.Copy
stateTimer = New Timer(tcb, "", 20000, 200000)
GC.KeepAlive(stateTimer)
End Sub
End Class
Global.asax:
<%# Application Language="VB" %>
<script runat="server">
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
End Sub
Sub Application_End(ByVal sender As Object, ByVal e As EventArgs)
' Code that runs on application shutdown
End Sub
Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
' Code that runs when an unhandled error occurs
End Sub
Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
' Code that runs when a new session is started
Dim FS As New fileSweeper
FS.Main()
End Sub
Sub Session_End(ByVal sender As Object, ByVal e As EventArgs)
' Code that runs when a session ends.
' Note: The Session_End event is raised only when the sessionstate mode
' is set to InProc in the Web.config file. If session mode is set to StateServer
' or SQLServer, the event is not raised.
End Sub
</script>
You are probably going to get unexpected results here because you are likely going to get multiple sessions on a web server. You might want to consider creating a console app and using windows task scheduler.
Related
I have been able to run an external program using the following code.
Imports System.Runtime.InteropServices
Public Class Form1
<DllImport("user32.dll")> Public Shared Function SetParent(ByVal hwndChild As IntPtr, ByVal hwndNewParent As IntPtr) As Integer
End Function
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim PRO As Process = New Process
PRO.StartInfo.FileName = ("notepad.exe")
PRO.Start()
Do Until PRO.WaitForInputIdle = True
'Nothing
Loop
SetParent(PRO.MainWindowHandle, Me.Handle)
PRO.Dispose()
End Sub
This works fine..... (for notepad that is)
However If I swich notepad for my own vb.net application it fails to launch that aplication inside the form but rather runs it outside of the form. I thought that the application I am trying to launch might of had somthing in it so I created a new application with nothing in it (as bare as I could get it) and run that instead of notepad but it also fails to launch within its "parent" form but rather it also triggers outside of the "parent" form insted?
Could someone please help me fix this?
You just need to wait a tiny bit longer for the MainWindowHandle property to be populated.
Here's a kludge that'll do it:
Private Async Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim PRO As Process = New Process
PRO.StartInfo.FileName = ("C:\Users\mikes\Desktop\temp.exe")
PRO.Start()
Await Task.Run(Sub()
PRO.WaitForInputIdle()
While PRO.MainWindowHandle.Equals(IntPtr.Zero)
Threading.Thread.Sleep(10)
End While
End Sub)
SetParent(PRO.MainWindowHandle, Me.Handle)
End Sub
If you want a ten second fail-safe, and exceptions caught, then you could change it up to:
Private Async Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Try
Dim PRO As Process = New Process
PRO.StartInfo.FileName = ("C:\Users\mikes\Desktop\temp.exe")
PRO.Start()
Await Task.Run(Sub()
Dim timeout As DateTime = DateTime.Now.AddSeconds(10)
While timeout > DateTime.Now AndAlso PRO.MainWindowHandle.Equals(IntPtr.Zero)
Threading.Thread.Sleep(10)
End While
End Sub)
If (Not PRO.MainWindowHandle.Equals(IntPtr.Zero)) Then
SetParent(PRO.MainWindowHandle, Me.Handle)
Else
MessageBox.Show("Timed out waiting for main window handle.", "Failed to Launch External Application")
End If
Catch ex As Exception
MessageBox.Show(ex.ToString, "Failed to Launch External Application")
End Try
End Sub
Imports System.Messaging
Imports System.Collections
Imports MSMQ
Imports System.IO
Imports System
Imports System.Messaging.MessageQueue
Imports System.Runtime.InteropServices
Public Class PauseOutMessages
'Declare everything to be in the scope of all methods.
Dim mgmt As New MSMQManagement
Dim outqmgmt As MSMQOutgoingQueueManagement
Dim q As New MSMQApplication
Dim outgoingQueues As New ArrayList
Dim myQueue As New MessageQueue("FormatName:DIRECT=OS:myMachine\Private$\myQueue", QueueAccessMode.ReceiveAndAdmin)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
For Each queue In q.ActiveQueues
If queue.IndexOf("DIRECT=") >= 0 Then
outgoingQueues.Add(queue)
End If
Next
End Sub
Private Sub Pause_Click(sender As Object, e As EventArgs) Handles Pause.Click
For Each queuePath In outgoingQueues
mgmt.Init(FormatName:=queuePath)
outqmgmt = mgmt.Pause()
Next
End Sub
Private Sub Restart_Click(sender As Object, e As EventArgs) Handles Restart.Click
For Each queuePath In outgoingQueues
mgmt.Init(FormatName:=queuePath)
outqmgmt = mgmt.Resume()
Next
End Sub
Private Sub Send_Click(sender As Object, e As EventArgs) Handles Send.Click
myQueue.Send("Test")
For Each queue In q.ActiveQueues
If queue.IndexOf("DIRECT=") >= 0 Then
outgoingQueues.Add(queue)
End If
Next
End Sub
End Class
Here is the code I am using, by sending the test message to a non-existing path it gets stuck in the outgoing queue where I want to be able to call MSMQOutgoingQueueManagement.Pause or .Resume to be able to start and stop all outgoing queues.
However I keep getting an error on either mgmt.Pause() or mgmt.Resume() saying Access is denied. I can't seem to find a way to get on to the properties of outgoing queues to be able to adjust security settings. Any help would be greatly appreciated!
SOLVED!
Turns out I just needed to start up visual studio as an administrator and then it worked.
I have a button which on click will run a Sub, creating a process which runs a script.
When this script is finished an Exited handler will fire and run another Sub which cleans up so that the application is ready to go anew without restarting it.
I disable the button during the run and try to re-enable it when the Exit is fired, however it tells me that the button is in another thread. So I tried using SynchronizedContext and Post:
Declared at the start of my class:
Class MainWindow
Private sc As SynchronizationContext = SynchronizationContext.Current
Not sure if I'm doing that correctly but it worked for me elsewhere in the code where I had the same problem.
The exit handling sub:
Private Sub CMD_Exited(ByVal sender As Object, ByVal e As EventArgs)
myProcess.CancelOutputRead()
myProcess.CancelErrorRead()
sc.Post(AddressOf Button_Click, Button1.IsEnabled = True)
Close()
End Sub
Which errors:
Method 'Private Sub Button_Click(sender As Object, e As RoutedEventArgs)' does not have a signature compatible with delegate 'Delegate Sub SendOrPostCallback(state As Object)'.
What can I do here? Changing the button signature will cause incompatibilities elsewhere.
Are there better ways to get around this threads issue?
Visual Vincent is correct, you need to invoke on the UI thread. Specifically you need to read this How to: Make Thread-Safe Calls to Windows Forms Controls.
Public Delegate Sub DoProcessStuffOnUIThreadHandler()
Private Sub CMD_Exited(ByVal sender As Object, ByVal e As EventArgs)
If Me.Button1.InvokeRequired Then
Dim d As New DoProcessStuffOnUIThreadHandler(AddressOf DoProcessStuffOnUIThread)
Me.Button1.Invoke(d)
Else
DoProcessStuffOnUIThread()
End If
End Sub
Private Sub DoProcessStuffOnUIThread()
myProcess.CancelOutputRead()
myProcess.CancelErrorRead()
Button1.IsEnabled = True
Close()
End Sub
(28-SEP-2017) Edit to add an alternative, that I used frequently in my WinForms code days, for brevity:
Public Delegate Sub DoProcessStuffOnUIThreadHandler()
Private Sub CMD_Exited(ByVal sender As Object, ByVal e As EventArgs)
If Me.Button1.InvokeRequired Then
Dim d As New DoProcessStuffOnUIThreadHandler(AddressOf CMD_Exited)
Me.Button1.Invoke(d)
Else
myProcess.CancelOutputRead()
myProcess.CancelErrorRead()
Button1.IsEnabled = True
Close()
End If
End Sub
The added example simply reduces code use. Both examples end in the same result. Hope that helps.
I have main forms that has a button that opens a master-customer on datagrid. I use dataview for the purpose of filtering the data using dataview.rowfilter.
The problem is, during the form load. It takes 5-6 seconds (the program is unresponsive during that time). What I'm trying to do is to load the data to the dataview on the background and show it on the gridview on workercompleted.
it gave me this error: "An error occurred creating the form. See Exception.InnerException for details. The error is: Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it." --> on dowork
I read somewhere that i should use Invoke. But i don't know how to use it.
here is my code:
Private Sub custcall_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
TBfind.Enabled = False
SetMyCustomFormat("yyyy-MM-dd HH:mm:ss")
BWcustload.RunWorkerAsync()
End Sub
Private Sub BWcustload_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BWcustload.DoWork
mydataview = New DataView(datatablecust)
End Sub
Private Sub BWcustload_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BWcustload.RunWorkerCompleted
DGVcustomer.DataSource = mydataview
TBfind.Enabled = True
End Sub
Have you tried moving the code to the event Form_Shown?
Also, have you tried putting the code in your DoWork section inside a SyncLock?
Try this:
SyncLock mydataview
mydataview = New DataView(datatablecust)
End SyncLock
As for the STA model ... try adding this to your code and set the startup object to Sub Main()
<STAThread()> _
Public Shared Sub Main()
Dim mainForm As New custcall()
Application.Run(mainForm)
End Sub
EDITED:
As far as invoke is concerned. ... that would definitely work, too ... but I don't know that it would have solved the STAThread issue.
To use invoke, first you have to declare a delegate sub in your form:
Delegate Sub LoadDataCallback()
Declare a function to take care of the actual loading of the data:
Private Sub LoadData()
mydataview = New DataView(datatablecust)
End Sub
Then, you would start a new thread in your Shown event (or Load event):
Dim mythread As New Thread(Sub()
Dim callLoad As New LoadDataCallBack(LoadData)
Me.Invoke(callLoad)
End Sub)
mythread.Start()
This gets around having to use SyncLock (although in some cases you may want to if it doesn't end up working correctly).
Don't forget to add Imports System.Threading to the top of your code file.
I have a project in VSTO/VB using a BackgroundWorker that works fine. It is a form that calls for a web page of information. The web page can take a while, so I have the form calling with the BackgroundWorker.
I then have an Excel Addin project that has added the BackgroundWorker project. When I call up the form from the Excel Addin project and use the BackgroundWorker to request the web page, it grabs the web page ok. But the work done upon completion, during the BackgroundWorker1_RunWorkerCompleted method, is resulting in an error message:
"Cross-thread operation not valid: Control 'TabPage2' accessed from a thread other than the thread it was created on."
Why does the BackgroundWorker project not work when called from the Excel Addin project?
I note that when I set the BackgroundWorker project as the "Startup Project" there is no error generated. Its something to do with calling this BackgroundWorker project from the Excel Addin project.
Edit: Could be that I am calling RunWorkerAsync() from a non UI thread?
I have an Excel Addin project with a Ribbon class. The Ribbon1.vb has a button click method that creates an instance of the second project, from which the backgroundworker will be called:
Private Sub Btn_Click(ByVal sender As System.Object, ByVal e As Microsoft.Office.Tools.Ribbon.RibbonControlEventArgs) Handles Btn.Click
Dim MySecondProject As SecondProject.Form1 = New SecondProject.Form1()
MySecondProject.Show()
End Sub
MySecondProject is then calling the BackgroundWorker from within its own button click method as:
BackgroundWorker1.RunWorkerAsync()
Then, after it completes, the backgroundworker is trying to update a label in MySecondProject:
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
SuccessLabel.Text = "Success!"
End Sub
When MySecondProject was the Startup Project, the backgroundworker kept track of the correct thread and updated the label successfully upon completion. With the Excel Addin as the Startup Project, and MySecondProject instantiated during runtime, the backgroundworker seems to lose track of the correct thread. Should I manually be inserting Invoke or BeginInvoke somewhere to help the backgroundworker keep track of the correct thread to update?
So, it turns out that a Backgroundworker launched from a Form launched from a Ribbon cannot update a control at the end of processing. I am not sure why it works from a Form launched as a Startup project while it does not work from a form launched from the Ribbon, but there it is -- turns out that you need to deal with the Backgroundworker losing track of the UI thread.
Using a MethodInvoker works, as in the following snippet:
Imports System.Windows.Forms
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
BackgroundWorker1.RunWorkerAsync()
End Sub
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
[do nothing]
End Sub
Private myString As String = "This is my string"
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
If Label1.InvokeRequired Then
Dim mi As MethodInvoker = AddressOf UpdateFormText
Label1.BeginInvoke(mi)
Else
Label1.Text = myString
End If
End Sub
Private Sub UpdateFormText()
Label1.Text = myString + " (BeginInvoked)"
End Sub
End Class
A better answer in VS2010 would use an inline MethodInvoker instead of the second function:
Me.Invoke(CType(Sub() Me.Label1.Text = "This is my string", MethodInvoker))