digital

VB.NET 下载文件及显示进程

简单的下载

1.创建 WebClient 类，再输入要下载的资源 url 地址还有本地保存路径即可。

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Dim DownloadClient As New Net.WebClient() 
DownloadClient.DownloadFile(yoururladdress,yourfileaddress)

2.使用 DownloadFile 的方法下载文件，指定文件的下载地址和本地路径，和超时时间。

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My.Computer.Network.DownloadFile(yoururladdress, yourfileaddress, False, 500)

具有进度提示的下载

以 VS2015 为编译环境，举例如下：

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Imports System.Net
Public Class Main

	Dim DownloadClient As New WebClient

	Private Sub Form_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
		AddHandler DownloadClient.DownloadProgressChanged, AddressOf ShowDownProgress 
		AddHandler DownloadClient.DownloadDataCompleted, AddressOf DownloadDataCompleted
	End Sub

	Private Sub Button_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button.Click
		DownLoadFiles()
	End Sub

	Private Sub DownLoadFiles()  
		 DownloadClient.DownloadFileAsync(New Uri(yourlink), (yoursaveaddress))
	End Sub

	Private Sub ShowDownProgress(ByVal sender As Object, ByVal e As DownloadProgressChangedEventArgs)
		Invoke(New Action(Of Integer)(Sub(i) ProgressBar.Value = i), e.ProgressPercentage)
	End Sub

	Sub DownloadDataCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.AsyncCompletedEventArgs)
		MessageBox.Show("下载成功！", "提示", MessageBoxButtons.OK)
	End Sub
End Class
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