4 つの Web クライアントを使用して 4 つのファイルを同時にダウンロードしようとしています。4 つのファイルすべてを同時にダウンロードしますが、最初の 2 つのプログレス バーは正常に動作し、3 番目のプログレス バーは 1 番目のプログレス バーと正確に移動し、4 番目のプログレス バーは 2 番目のプログレス バーと正確に移動します。これが問題に関連する私のコードです。
Public WithEvents downloadFile1 As WebClient
Public WithEvents downloadFile2 As WebClient
Public WithEvents downloadFile3 As WebClient
Public WithEvents downloadFile4 As WebClient
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
System.Net.ServicePointManager.DefaultConnectionLimit = 10
End Sub
Private Sub startDownloadFile1()
downloadFile1 = New WebClient
Dim targetURL As String = lstURLs.Items.Item(0)
Dim destinationPath As String = "e:\Downloads\0.jpg"
downloadFile1.DownloadFileAsync(New Uri(targetURL), destinationPath)
End Sub
Private Sub startDownloadFile2()
downloadFile2 = New WebClient
Dim targetURL As String = lstURLs.Items.Item(1)
Dim destinationPath As String = "e:\Downloads\1.jpg"
downloadFile2.DownloadFileAsync(New Uri(targetURL), destinationPath)
End Sub
startDownloadFile3() および startDownloadFile() についても同様です。
Private Sub btnDownload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDownload.Click
startDownloadFile1()
startDownloadFile2()
startDownloadFile3()
startDownloadFile4()
End Sub
Private Sub downloadFile1_DownloadProgressChanged(ByVal sender As Object, ByVal e As System.Net.DownloadProgressChangedEventArgs) Handles downloadFile1.DownloadProgressChanged
pb1.Value = e.ProgressPercentage
End Sub
Private Sub downloadFile2_DownloadProgressChanged(ByVal sender As Object, ByVal e As System.Net.DownloadProgressChangedEventArgs) Handles downloadFile2.DownloadProgressChanged
pb2.Value = e.ProgressPercentage
End Sub
Private Sub downloadFile3_DownloadProgressChanged(ByVal sender As Object, ByVal e As System.Net.DownloadProgressChangedEventArgs) Handles downloadFile1.DownloadProgressChanged
pb3.Value = e.ProgressPercentage
End Sub
Private Sub downloadFile4_DownloadProgressChanged(ByVal sender As Object, ByVal e As System.Net.DownloadProgressChangedEventArgs) Handles downloadFile2.DownloadProgressChanged
pb4.Value = e.ProgressPercentage
End Sub