Question

有一些主要表单，我从FTP调用文件下载。当我提出这个操作时，我希望看到新的表单ShowDialog和它上面的进度条同时显示，然后显示进度并关闭新表单并返回主表单。然而，我的代码正在工作，当它将处理时，我的主窗体冻结，然后在新窗体出现然后关闭时。我想纠正的是显示这个新表格在执行过程后立即显示。你能看看并告诉我什么是错的吗？

这是我的主要形式下载过程：

Dim pro As New FrmProgressBarWinscp(WinScp, myremotePicturePath, ladujZdjeciaPath, True)

FrmProgressBarWinscp如下：

Public Class FrmProgressBarWinscp

    Property _winScp As WinScpOperation
    Property _remotePicture As String
    Property _ladujZdjecia As String
    Property _removesource As String

    Public Sub New()
        InitializeComponent()
    End Sub

    Sub New(winscp As WinScpOperation, remotePicture As String, ladujzdjecia As String, removesource As Boolean)
        ' This call is required by the designer.
        InitializeComponent()
        ' Add any initialization after the InitializeComponent() call.
        _winScp = winscp
        _remotePicture = remotePicture
        _ladujZdjecia = ladujzdjecia
        _removesource = removesource
        ShowDialog()
    End Sub

    Sub Run()

        Try
            Cursor = Cursors.WaitCursor
            _winScp.GetFile(_remotePicture, _ladujZdjecia, _removesource)
            ProgressBar1.Minimum = 0
            ProgressBar1.Maximum = 1
            ProgressBar1.Value = 0
            Do
                ProgressBar1.Value = WinScpOperation._lastProgress
                ProgressBar1.Refresh()
            Loop Until ProgressBar1.Value = 1
            Cursor = Cursors.Default
            'Close()

        Catch ex As Exception

        Finally
            If _winScp IsNot Nothing Then
                _winScp.SessionDispose()
            End If

            System.Threading.Thread.Sleep(10000)
            Close()
        End Try

    End Sub

    Private Sub FrmProgressBarWinscp_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Run()
    End Sub
End Class

Winscp我自己的类并使用了方法：

...
Function GetFile(source As String, destination As String, Optional removeSource As Boolean = False)
    Dim result As Boolean = True
    Try

        session.GetFiles(source, destination, removeSource).Check()

    Catch ex As Exception
        result = False
    End Try
    Return result
End Function

Private Shared Sub SessionFileTransferProgress(sender As Object, e As FileTransferProgressEventArgs)
    'Print transfer progress
    _lastProgress = e.FileProgress

End Sub

Public Shared _lastProgress As Integer

...

进一步讨论nr 3：

Main form:
 Dim tsk As Task(Of Boolean) = Task.Factory.StartNew(Of Boolean)(Function()
                                                                                                Return WinScp.GetFile(myremotePicturePath, ladujZdjeciaPath, True)

                                                                                            End Function)


                            Dim forma As New FrmProgressBar
                            forma.ShowDialog()

进度条表格

Public Class FrmProgressBar

    Public Sub New()
        InitializeComponent()
    End Sub
    Sub Run()
        Try
            Do
                ProgressBar1.Value = WinScpOperation._lastProgress
                ProgressBar1.Refresh()
            Loop Until ProgressBar1.Value = 1
            Cursor = Cursors.Default

        Catch ex As Exception
        Finally
            MsgBox("before sleep")
            System.Threading.Thread.Sleep(10000)
            MsgBox("after sleep sleep")
            Close()
        End Try
    End Sub

    Private Sub FrmProgressBarWinscp_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Run()
    End Sub
End Class

点nr。 4：

  Dim tsk As Task(Of Boolean) = Task.Factory.StartNew(Of Boolean)(Function()
                                                                                                Return WinScp.GetFile(myremotePicturePath, ladujZdjeciaPath, True)

                                                                                            End Function)


                            Dim pic As New Waiting
                            pic.ShowDialog()

                            Task.WaitAll(tsk)
                            pic.Close()

第5点：

 Dim pic As New Waiting
                            pic.ShowDialog()
                            Dim tsk As Task = Task.Factory.StartNew(Sub() WinScp.GetFile(myremotePicturePath, ladujZdjeciaPath, pic, True))




                            Task.WaitAll(tsk)
                            'pic.Close()

在其他一些类中（也许在此方法被放入不同类之前未提及 - 我的自定义类）

Public Function GetFile(source As String, destination As String, formclose As InvokeCloseForm, Optional removeSource As Boolean = False) As Boolean
        Dim result As Boolean = True
        Try
            session.GetFiles(source, destination, removeSource).Check()
        Catch ex As Exception
            result = False
        End Try
        formclose.RUn()
        Return result
    End Function

接口：

Public Interface InvokeCloseForm
    Sub RUn()
End Interface

等待表格：

Public Class Waiting
    Implements InvokeCloseForm

    Public Sub RUn() Implements InvokeCloseForm.RUn
        Me.Close()
    End Sub
End Class

Answer 1

阻止中的Session.GetFiles method。

这意味着它只在转移完成后返回。

解决方案是：

在单独的线程中运行WinSCP传输（Session.GetFiles），而不是阻止GUI线程。

请参阅WinForm Application UI Hangs during Long-Running Operation
处理Session.FileTransferProgress event。

虽然请注意事件处理程序将在后台线程上调用，因此您无法直接从处理程序更新进度条。您必须使用Control.Invoke来确保在GUI线程上更新进度条。

请参阅How to update the GUI from another thread in C#?

一个简单的实现就像：

Public Class ProgressDialog1

    Private Sub ProgressDialog1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' Run download on a separate thread
        ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf Download))
    End Sub

    Private Sub Download(stateInfo As Object)
        ' Setup session options
        Dim mySessionOptions As New SessionOptions
        With mySessionOptions
            ... 
        End With

        Using mySession As Session = New Session
            AddHandler mySession.FileTransferProgress, AddressOf SessionFileTransferProgress

            ' Connect
            mySession.Open(mySessionOptions)

            mySession.GetFiles(<Source>, <Destination>).Check()
        End Using

        ' Close form (invoked on GUI thread)
        Invoke(New Action(Sub() Close()))
    End Sub

    Private Sub SessionFileTransferProgress(sender As Object, e As FileTransferProgressEventArgs)
        ' Update progress bar (on GUI thread)
        ProgressBar1.Invoke(New Action(Of Double)(AddressOf UpdateProgress), e.OverallProgress)
    End Sub

    Private Sub UpdateProgress(progress As Double)
        ProgressBar1.Value = progress * 100
    End Sub
End Class

如果您想阻止用户进行某些操作，您可能希望在操作期间禁用进度表单（或其部分）。

使用表单或控件的.Enabled属性。

更容易，但是hacky且通常不推荐的解决方案是从现有的Application.DoEvents处理程序中调用SessionFileTransferProgress方法。

当然，您还必须从SessionFileTransferProgress更新进度条。

Private Shared Sub SessionFileTransferProgress(sender As Object, e As FileTransferProgressEventArgs)
    'Print transfer progress
    ProgressBar1.Value = e.FileProgress
    Application.DoEvents
End Sub

进度条的.Minimum和.Maximum必须在Session.GetFiles之前设置。

但不要那样做！这是一种错误的做法。

然而，您需要以与上述正确解决方案相同的方式禁用表单/控件。

在WinForm的进度条上显示WinSCP .NET程序集传输进度

1 个答案: