Question

我正在尝试创建一个简单的下载应用程序，该应用程序从文本文件和下载文件的所需文件名中获取链接，然后下载它。我已经完成了代码，但是当我运行应用程序时，没有任何反应。没有运行时错误，我无法在代码或逻辑中找出问题。

以下是完整的代码：

Imports System.Net

Public Class Form1

' the file has filename,link. Each even number is a filename, and odd number is a link
' program loads it seperately into different array
' then download the file with and save with it's filename

Dim WithEvents WC As New WebClient

Private Sub backgroundDownloader_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles backgroundDownloader.DoWork
    Dim lines() As String = IO.File.ReadAllLines("down.txt")
    Dim counter As Integer = 0
    Dim file As String
    Dim path = "downloads\"

    ' filenames will be the same amount as links and vise-versa
    ' that means filenames and links are exactly half the size of total lines of files
    Dim filenames(lines.Length / 2) As String
    Dim links(lines.Length / 2) As String

    ' store value in arrays
    While counter < lines.Length
        ' using modulus operator to test odd or even counter
        If counter Mod 2 = 0 Then
            filenames(counter) = lines(counter)
            counter += 1
        Else
            links(counter) = lines(counter)
            counter += 1
        End If
    End While
    counter = 0

    ' add path to each filename
    Dim temp As String
    For Each file In filenames
        temp = ""
        temp = path + file
        file = temp
    Next

    'start download
    While counter < links.Length
        WC.DownloadFileAsync(New Uri(links(counter)), filenames(counter))
        counter += 1
    End While
End Sub

Private Sub WC_DownloadProgressChanged(ByVal sender As Object, ByVal e As DownloadProgressChangedEventArgs) Handles WC.DownloadProgressChanged

    ' update progressbar status
    progressBar1.Value = e.ProgressPercentage

    ' change status when done status when download completes
    If progressBar1.Value = 100 Then
        lblStatus.Text = "Downloads Completed!"
        picStatus.Image = Image.FromFile("resources\images\done.png")
    End If
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    backgroundDownloader.RunWorkerAsync()
End Sub
End Class

以下是down.txt（存储名称和链接的文件）的内容：

first.bin
https://speed.hetzner.de/100MB.bin
second.bin
https://speed.hetzner.de/100MB.bin
third.bin
https://speed.hetzner.de/100MB.bin
fourth.bin
https://speed.hetzner.de/100MB.bin

callstack没有显示任何内容。它在内存和变量窗口中都是空白的，如屏幕截图所示：screenshot

任何帮助或建议都会表示赞赏。谢谢。

编辑（1） - 增加计数器变量。

EDIT（2） - 现在使用临时字符串添加文件名

的路径

下载程序应用程序.NET

0 个答案: