Question

如果有人可以帮助我，我真的很感激。如果我点击发送按钮，则无法在此之后下载log.txt ...

Imports System
Imports System.IO
Imports System.Collections
Imports System.Security.Principal
Imports System.Runtime.InteropServices
Imports System.Net

Public Class Form1
Public sent As Boolean = False
Private Declare Function SHChangeNotify Lib "Shell32.dll" (ByVal wEventID As Int32, _
                                                           ByVal uFlags As Int32, _
                                                           ByVal dwitem1 As Int32, _
                                                           ByVal deitem2 As Int32) As Int32

Private Sub send_Click(sender As Object, e As EventArgs) Handles send.Click
    'If a message has been sent
    sent = True
    Try
        Dim writer As New System.IO.StreamWriter(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt")
        sent = False
        writer.Write(input.Text)
        Try
            Dim ftp As FtpWebRequest = DirectCast(WebRequest.Create("ftp://***/c/log.txt"), FtpWebRequest)
            ftp.Method = WebRequestMethods.Ftp.DeleteFile
            Dim ftpResponse As FtpWebResponse = CType(ftp.GetResponse(), FtpWebResponse)
            ftpResponse = ftp.GetResponse()
            ftpResponse.Close()
        Catch ex As Exception

        End Try
        My.Computer.Network.UploadFile(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt", New Uri("ftp://***/c/log.txt"), "user", "pass", False, 30000, FileIO.UICancelOption.DoNothing)
        input.Text = ""
    Catch ex As Exception

    End Try
    sent = False
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    If Not File.Exists(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c") Then
        My.Computer.FileSystem.CreateDirectory(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c")
    Else
        My.Computer.FileSystem.DeleteDirectory(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c", FileIO.DeleteDirectoryOption.DeleteAllContents)
        My.Computer.FileSystem.CreateDirectory(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c")
    End If
    firstcheck()
    Threading.Thread.Sleep(500)
End Sub

Private Sub taskbarcheck_Tick(sender As Object, e As EventArgs) Handles taskbarcheck.Tick
    If File.Exists(My.Computer.FileSystem.SpecialDirectories.Desktop & "\chax.txt") Then
        Me.Opacity = 100
        Me.Show()
        Try
            My.Computer.FileSystem.DeleteFile(My.Computer.FileSystem.SpecialDirectories.Desktop & "\chax.txt")
        Catch ex As Exception

        End Try
        Threading.Thread.Sleep(50)
        SHChangeNotify(&H8000000, &H1000, 0, 0)
    End If
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles btn_hide.Click
    Try
        My.Computer.FileSystem.DeleteFile(My.Computer.FileSystem.SpecialDirectories.Desktop & "\chax.txt")
    Catch ex As Exception

    End Try
    Me.Opacity = 0
    Me.Hide()
    Threading.Thread.Sleep(50)
    SHChangeNotify(&H8000000, &H1000, 0, 0)
End Sub

Private Sub ftpstuff_Tick(sender As Object, e As EventArgs) Handles ftpstuff.Tick
    'Try
    'delete file if exists
    Try
        My.Computer.FileSystem.DeleteFile(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt")
    Catch ex As Exception

    End Try
    'download file
    Try
        My.Computer.FileSystem.DeleteFile(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt")
    Catch ex As Exception

    End Try
    'My.Computer.Network.DownloadFile("http://***/c/log.txt", My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt", "", "", False, 30000, False)
    Dim myWebClient As New WebClient()
    If Not sent = True Then
        myWebClient.DownloadFile("http://***/c/log.txt", My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt")
        log.Text = File.ReadAllText(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt")
    End If
End Sub

Private Sub firstcheck()
    If Not File.Exists(My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt") Then
        My.Computer.Network.DownloadFile(New Uri("ftp://***/c/log.txt"), My.Computer.FileSystem.SpecialDirectories.MyDocuments & "\c\log.txt", "user", "pass", False, 30000, True, FileIO.UICancelOption.DoNothing)
    End If
End Sub

我按照我所知道的方式尝试了一下......当我点击发送按钮后尝试下载文件时，会抛出“System.dll中出现未处理的类型'System.Net.WebException'的异常”

提前感谢您的帮助！

Answer 1

是的，这是没有关闭的流。谢谢！

Answer 2

如果在流关闭之前出现异常，则代码会直接跳转到catch块，并且流永远不会关闭。我假设文件被锁定，直到程序终止。

尝试添加命令以关闭Catch块以及Try块中的文件

下载文件时抛出随机错误

2 个答案: