我的网页浏览器只能使用https链接？

Question

我正在使用Visual Studio 2015社区版和Visual Basic制作一个简单的网络浏览器。我已经添加了下面的代码。我的浏览器工作，但我的问题是，它似乎只能用于HTTPS协议链接。我认为这是因为http会自动抛出一个错误，这会导致我的错误处理程序运行，这会使用https前缀重试网站。但是我不知道那个错误可能是什么或者如何解决它......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，只专注于“公共子GoButton_clicked”后的位......

Answer 1

你试图使用旧VB6风格的错误处理。正如上面的评论表明，在VB.Net中使用更新的Try \ Catch语法会更好。

如果你想保留它写它是这样的...

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 

注意“退出小组”，以防止它进入了错误处理代码，如果没有错误。它会按照目前的状况进行操作，因此您可能根本没有任何错误，只是无意中无意间刷新了页面。

加上有错误的变量，你可以在错误处理查见Err.Description和Err.Number的