WebClient 使用

Sub DownloadFile(ByVal uri As String, ByVal destFile As String, _
Optional ByVal username As String = Nothing, Optional ByVal pwd As String = _
Nothing)
Dim wc As New System.Net.WebClient
If Not username Is Nothing AndAlso Not pwd Is Nothing Then
wc.Credentials = New System.Net.NetworkCredential(username, pwd)
End If

wc.DownloadFile(uri, destFile)
End Sub