我的网络浏览器仅适用于https链接？

Question

我正在使用Visual Studio 2015 Community Edition和Visual Basic制作一个简单的Web浏览器。我在下面添加了代码。我的浏览器工作正常，但我的问题是它似乎只能使用HTTPS协议链接。我认为这是因为http会自动抛出一个错误，导致我的错误处理程序运行，它会使用https前缀重试网站。但是我不知道那个错误是什么或如何解决它...你能帮忙吗？

CODE：

Public Class Form1
    'One button for go. Other for settings -incognito, history, homepage????


'Window button actions

Private Sub Green_Click(sender As Object, e As EventArgs) Handles Green.Click
    Me.WindowState = FormWindowState.Maximized
End Sub

Private Sub Yellow_Click(sender As Object, e As EventArgs) Handles Yellow.Click
    Me.WindowState = FormWindowState.Minimized
End Sub

Private Sub Red_Click(sender As Object, e As EventArgs) Handles Red.Click
    Me.Close()
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
    TitleText.Parent = Grey
    TitleText.BackColor = Color.Transparent

    TitleTextDivider.Parent = Grey
    TitleTextDivider.BackColor = Color.Transparent

    VersionText.Parent = Grey
    VersionText.BackColor = Color.Transparent
End Sub

Public Sub GoButton_Click(sender As Object, e As EventArgs) Handles GoButton.Click
    'Add checking blacklist and adding link to history file here later. Use separate subs and call them here for better organisation.

    Dim Input As String = TextBox1.Text
    'Prefix with http and www
    Input = "http://www." + Input
    'Convert to Uri
    Dim Url As Uri = New Uri(Input)
    'Set as url
    WebBrowser1.Url = Url
    'Refresh
    WebBrowser1.Refresh()
    'On error, retry with https
    On Error GoTo HTTPS_Handler
HTTPS_Handler:
    'New String URL, replacing http with https
    Dim HTTPS_Input As String = Replace(Input, "http", "https")
    'All we did last time, again...
    Dim NewUrl As Uri = New Uri(HTTPS_Input)
    WebBrowser1.Url = NewUrl
    WebBrowser1.Refresh()
End Sub
End Class

不要担心第一位，只关注“Public sub GoButton_clicked”之后的位......

Answer 1

您尝试使用旧的VB6样式的错误处理。正如上面的评论所表明的那样，在VB.Net中使用更新的Try \ Catch语法会更好。

如果你想让它像这样写...

Public Sub GoButton_Click(sender As Object, e As EventArgs) Handles GoButton.Click
    On Error GoTo HTTPS_Handler

    Dim Input As String = TextBox1.Text
    Input = "http://www." + Input

    Dim Url As Uri = New Uri(Input)
    WebBrowser1.Url = Url
    WebBrowser1.Refresh()

    Exit Sub

HTTPS_Handle:
    Dim HTTPS_Input As String = Replace(Input, "http", "https")
    Dim NewUrl As Uri = New Uri(HTTPS_Input)
    WebBrowser1.Url = NewUrl
    WebBrowser1.Refresh()
End Sub

如果没有错误，请注意“退出Sub”以防止它进入错误处理代码。它目前正在做什么，所以你可能没有任何错误，只是无意中刷新了页面。

另外，您可以在错误处理中查看错误变量，请参阅Err.Description和Err.Number