Aidan Kehoe Aidan Kehoe - 6 months ago 73
Vb.net Question

BackgroundWorker is busy vb.net

I am trying to run time consuming tasks in a backgroundWorker so that the progress bar can be updated. However, the backgroundWorker never runs because I always get an error saying the worker is currently busy even though I only call it once. I tried debugging the code where I run the background worker using this:

Private Sub saveBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles saveBtn.Click
Dim k As Boolean = BackgroundWorker1.IsBusy
Debug.Print(k)
BackgroundWorker1.RunWorkerAsync()

End Sub


What I found was that the saveBtn_Click sub would loop through twice for some reason. So, the background worker would originally not be busy, then it would run, saveBtn_Click would loop through again and the backgroundWorker would be busy. Why is saveBtn_click looping through twice? Here is the DoWork code:

Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
'Declare variables used in conjunction with solid edge
Dim objApplication As SolidEdgeFramework.Application = Nothing
Dim objDocument As SolidEdgeFramework.SolidEdgeDocument = Nothing
Dim objPropertySets As SolidEdgeFramework.PropertySets = Nothing
Dim objProperties As SolidEdgeFramework.Properties = Nothing
Dim objProperty As SolidEdgeFramework.Property = Nothing

'Declare variables related to file
Dim FileName As String
Dim FileName1 As Object
Dim ChosenFile As Object = Nothing
Dim NewFileNames(3) As String
Dim Extensions(2) As String
Dim Extension As String
Dim i, k As Integer
Dim counter As Integer
Dim temp As String


'Store required extensions into array
Extensions(0) = ".stp"
Extensions(1) = ".x_t"
Extensions(2) = ".igs"
Extension = ".dxf"

'Uses open dialog to allow for folder selection in required path
Dim dialog As New FolderBrowserDialog()
dialog.SelectedPath = "C:\Folder"
dialog.Description = "Select Folder"
If dialog.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
ChosenFile = dialog.SelectedPath
End If


Try

'Connects to solid edge
objApplication = Marshal.GetActiveObject("SolidEdge.Application")

'References the currently open document
objDocument = objApplication.ActiveDocument

'References the properties of the document
objPropertySets = objDocument.Properties

'Gets file name from open document
FileName = objDocument.Name

If objDocument.Type = DocumentTypeConstants.igDraftDocument Then
'Checks for the .asm extension in the file name (-4 is used so that the index does not surpass the string length)
For i = 0 To FileName.Length - 4
If FileName(i) = "." And FileName(i + 1) = "d" And FileName(i + 2) = "f" And FileName(i + 3) = "t" Then
counter = i
End If
Next

'Removes the .asm from the file name
temp = FileName.Remove(counter, 4)
FileName = temp


'Uses the file name as a default response for the input box
FileName1 = InputBox("Enter file Name", DefaultResponse:=FileName)
txt.Text = "File is being saved"

ProgressBar1.Value = 20

'Loops through properties to find name of file
'For i = 1 To objPropertySets.Count
' objProperties = objPropertySets.Item(i)
' For j = 1 To objProperties.Count
' objProperty = objProperties.Item(j)
' FileName = objProperty.Name
' Debug.Print(FileName)
' Next
'Next



'Creates a new file name that acts as the path of the file
NewFileNames(0) = ChosenFile & "\" & FileName1 & Extension & Extension

objDocument.SaveAs(NewFileNames(0))

ProgressBar1.Value = 60

'objDocument.SaveAs("C:\Folder", NewFileName1)
'objDocument.SaveAs("C:\Folder", NewFileName2)
'objDocument.SaveAs("C:\Folder", NewFileName3)

'Zips the file using Ionic.zip library
'For k = 0 To (NewFileNames.Count - 1)
' Using zip As ZipFile = New ZipFile
' zip.AddFile(NewFileNames(k))
' zip.Save(ChosenFile & "\" & FileName1 & "-" & Extensions(k) & ".zip")
' End Using
'Next

'Process.Start("C:\Programme\7-Zip\7za.exe", "a -tzip C:\Folder\files.7z C:\Folder\.*dxf")

'Execute7Zip("C:\Program Files\7-Zip", "7za.exe", NewFileNames(0), "C:\Folder\zippedfiles.zip")
Dim zippedLocation As String = Nothing
For i = 0 To NewFileNames(0).Length - 4
If NewFileNames(0)(i) = "." And NewFileNames(0)(i + 1) = "d" And NewFileNames(0)(i + 2) = "x" And NewFileNames(0)(i + 3) = "f" Then
counter = i
zippedLocation = NewFileNames(0).Remove(i, 4)
End If
Next


Shell("C:\Program Files\7-Zip\7z.exe a " + zippedLocation + ".zip " + NewFileNames(0))

ProgressBar1.Value = 100

MsgBox("Your file has been saved")

'Closes the window
Me.Dispose()
Else

'removes solid edge extension
FileName = FileName.Substring(0, FileName.Length - 4)
Debug.Print(FileName)

'Uses the file name as a default response for the input box
FileName1 = InputBox("Enter file Name", DefaultResponse:=FileName)
txt.Text = "File is being saved"


'Loops through properties to find name of file
'For i = 1 To objPropertySets.Count
' objProperties = objPropertySets.Item(i)
' For j = 1 To objProperties.Count
' objProperty = objProperties.Item(j)
' FileName = objProperty.Name
' Debug.Print(FileName)
' Next
'Next


'Creates a new file name that acts as the path of the file
For k = 0 To (Extensions.Length - 1)
NewFileNames(k) = ChosenFile & "\" & FileName1 & Extensions(k) & Extensions(k)
Next


For k = 0 To (NewFileNames.Count - 2)
objDocument.SaveAs(NewFileNames(k))
BackgroundWorker1.ReportProgress((k / (NewFileNames.Count - 2)) * 100)
System.Threading.Thread.Sleep(200)
Next



'objDocument.SaveAs("C:\Folder", NewFileName1)
'objDocument.SaveAs("C:\Folder", NewFileName2)
'objDocument.SaveAs("C:\Folder", NewFileName3)

'Zips the file using Ionic.zip library
'For k = 0 To (NewFileNames.Count - 1)
' Using zip As ZipFile = New ZipFile
' zip.AddFile(NewFileNames(k))
' zip.Save(ChosenFile & "\" & FileName1 & "-" & Extensions(k) & ".zip")
' End Using
'Next

'Process.Start("C:\Programme\7-Zip\7z.exe", "a -tzip C:\Folder\files.zip C:\Folder\*.stp")


'Execute7Zip("C:\Program Files\7-Zip", "7za.exe", NewFileNames(0), "C:\Folder\zippedfiles.zip")
Dim zippedLocation(2) As String
For j = 0 To NewFileNames.Length - 2
For i = 0 To NewFileNames(j).Length - 4
If NewFileNames(j)(i) = "." And NewFileNames(j)(i + 1) = "s" And NewFileNames(j)(i + 2) = "t" And NewFileNames(j)(i + 3) = "p" Then
counter = i
zippedLocation(j) = NewFileNames(j).Remove(i, 4)
zippedLocation(j) = zippedLocation(j).Replace(".", "-")
End If
If NewFileNames(j)(i) = "." And NewFileNames(j)(i + 1) = "x" And NewFileNames(j)(i + 2) = "_" And NewFileNames(j)(i + 3) = "t" Then
counter = i
zippedLocation(j) = NewFileNames(j).Remove(i, 4)
zippedLocation(j) = zippedLocation(j).Replace(".", "-")
End If
If NewFileNames(j)(i) = "." And NewFileNames(j)(i + 1) = "i" And NewFileNames(j)(i + 2) = "g" And NewFileNames(j)(i + 3) = "s" Then
counter = i
zippedLocation(j) = NewFileNames(j).Remove(i, 4)
zippedLocation(j) = zippedLocation(j).Replace(".", "-")
End If

Next
Next

Shell("C:\Program Files\7-Zip\7z.exe a " + zippedLocation(0) + ".zip " + NewFileNames(0))
Shell("C:\Program Files\7-Zip\7z.exe a " + zippedLocation(1) + ".zip " + NewFileNames(1))
Shell("C:\Program Files\7-Zip\7z.exe a " + zippedLocation(2) + ".zip " + NewFileNames(2))
Thread.Sleep(2000)
My.Computer.FileSystem.DeleteFile(NewFileNames(0))
My.Computer.FileSystem.DeleteFile(NewFileNames(1))
My.Computer.FileSystem.DeleteFile(NewFileNames(2))


MsgBox("Your file has been saved")

'Closes the window
Me.Dispose()
End If

'The error message opens if solid works is not open in the background
Catch ex As Exception
txt.Text = "Open Solid Edge"

'Releases each reference to solid work (freeing memory)
Finally
If Not (objDocument Is Nothing) Then
Marshal.ReleaseComObject(objDocument)
objDocument = Nothing
End If
If Not (objApplication Is Nothing) Then
Marshal.ReleaseComObject(objApplication)
objApplication = Nothing
End If

End Try
End Sub

Answer

Here is some code that i have written up for you to have a look at, it should lead you in the right direction and help you on your way in using a background worker:)

Imports System.ComponentModel

 Public Class Form1
''This will display the information to the textbox and will also load a progressbar(you can change it to something else beside a textbox too eg label, windows form title and so on).
Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
    TextBox1.Text = e.ProgressPercentage & "%"
    ProgressBar1.Value = e.ProgressPercentage
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    ''This is make the backgroundworker start at load up(change it to a button if need be
    CheckForIllegalCrossThreadCalls = False
    BackgroundWorker1.RunWorkerAsync()
    BackgroundWorker1.WorkerReportsProgress = True
End Sub

Private Sub BackgroundWorker1_DoWork(sender As Object, e As DoWorkEventArgs) Handles BackgroundWorker1.DoWork
    ''This is the example that i created to show you how to set a task.
    For i = 0 To 10000
        TextBox1.Text = i
        BackgroundWorker1.ReportProgress(i)
        System.Threading.Thread.Sleep(500)
    Next
End Sub

Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
    ''once the task is complete it will show a messagebox and reset the progressbars value to 0 so its not full when the task is compelete.
    MessageBox.Show("Completed")
    ProgressBar1.Value = 0
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    ''If you ever need to cancel the backgroundworkder when it is still running
    BackgroundWorker1.CancelAsync()
End Sub
End Class

Let me know how you go
Happy Coding