BackgroundWorker正忙vb.net

Question

我想在backgroundWorker中運行耗時的任務，以便進度條可以更新。然而，backgroundWorker從不運行，因爲我總是得到一個錯誤，說明工作人員目前很忙，即使我只調用一次。我試着調試代碼，我運行使用此背景工人：

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 

我發現那是什麼的saveBtn_Click子將通過兩次循環出於某種原因。所以，後臺工作人員本來不會忙，那麼它會運行，saveBtn_Click將再次循環，並且backgroundWorker會很忙。爲什麼saveBtn_click循環兩遍？這裏是DoWork代碼：

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 1

這裏是我已經寫了給你看看一些代碼，它應該引領你在正確的方向，並幫助你的方式，使用後臺工作:)

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 

讓我知道你如何去
編碼快樂

Answer 2

所有UI交互都必須在UI線程上發生，因此您不能從後臺線程顯示對話框。

查看c# backgroundworker won't work with the code I want it to do對於類似的問題（C＃而不是VB，但概念是相同的）。

問候 羅布