在没有Internet Explorer的情况下在VB.NET中下载文件

Imports System.Net

Public Class Form1
    Private Sub btnDownload_Click(sender As Object, e As EventArgs) Handles btnDownload.Click
        Dim url As String = "http://example.com/file.txt" ' 下载文件的URL
        Dim savePath As String = "C:\Downloads\file.txt" ' 保存文件的路径

        Dim client As New WebClient()
        AddHandler client.DownloadProgressChanged, AddressOf DownloadProgressChanged
        AddHandler client.DownloadFileCompleted, AddressOf DownloadFileCompleted

        client.DownloadFileAsync(New Uri(url), savePath)
    End Sub

    Private Sub DownloadProgressChanged(sender As Object, e As DownloadProgressChangedEventArgs)
        ' 下载进度变化时的处理逻辑
        Dim progress As Integer = e.ProgressPercentage
        ' 更新进度条或显示下载进度
    End Sub

    Private Sub DownloadFileCompleted(sender As Object, e As System.ComponentModel.AsyncCompletedEventArgs)
        ' 下载完成时的处理逻辑
        If e.Error IsNot Nothing Then
            ' 下载过程中发生错误
            MessageBox.Show("下载文件时发生错误：" & e.Error.Message)
        Else
            ' 下载完成
            MessageBox.Show("文件下载完成！")
        End If
    End Sub
End Class