程序的主角是一个ActiveX控件:WebBrowser。当然,缺省状态下VB的工具箱中并没有它,我们得手工加入,方法是:右击工具箱,在出现的快捷菜单中选择“部件...”,确保在弹出的对话框中选中“控件”标签,找到Microsoft Internet Controls,在它前面的小框中打钩,然后确定。此时你会发现工具箱中多了两个小图标,其中,地球图标代表的控件正是我们需要的WebBrowser。
   由于许多人对WebBrowser控件不是很熟悉,VB的帮助中也没有有关它的内容(反正我没有找到),因此有必要介绍一下它的属性、方法和事件,限于篇幅,我们只涉及程序中用到的:
   属性:LocationURL 返回控件显示WEB页面的URL。
   方法:Navigate 转移到指定的URL或打开指定HTML文件。
   事件:1.DownloadBegin 下载操作开时触发。
   2.DownloadComplete 下载操作完成、终止或失败时触发。
   3.ProgressChange WebBrowser控件跟踪下载操作的过程,并定期触发此事件。其语法为:Sub WebBrowser_ProgressChange (ByVal Progress As Long, ByVal ProgressMax As Long)。Progress变元是当前已下载的数据总量,ProgressMax变元是将要下载的数据总量。
   4.TitleChange 当前文档标题改变时触发
   除了WebBrowser控件外,程序还需要一个Label控件:Label1;一个ComboBox控件:
combo1,用来显示URL地址;一个StatusBar控件:StatusBar1;一个ProgressBar控件:
ProgressBar1,用来显示下载进度(StatusBar控件和ProgressBar控件是ActiveX控件Microsoft Windows Common Controls5.0的成员,加入工具箱的方法同WebBrowser控件),这些控件的属性值都用缺省值。
   以下是程序清单:
   Option Explicit

   Private Sub Form_Load()
   Me.Caption =“My Explorer”
   Label1.Caption = “URL”
   Combo1.Text = “”
   Combo1.Top = Label1.Height
   Combo1.Left = 0
   WebBrowser1.Top = Combo1.Top + Combo1.Height
   WebBrowser1.Left = 0
   Form_Resize
   StatusBar1.Style = sbrSimple
   ProgressBar1.ZOrder
   End Sub

   Private Sub Form_Resize()
   On Error GoTo a
   Combo1.Width = Form1.Width - 100
   WebBrowser1.Width = Combo1.Width
   WebBrowser1.Height = Form1.Height - Combo1.Height - 1000
   ProgressBar1.Top = Me.Height - StatusBar1.Height - 330
   ProgressBar1.Left = 0.25 * StatusBar1.Width
   ProgressBar1.Width = 0.75 * Me.Width - 250
   a:
   End Sub

   Private Sub Combo1_Click()
   `转到指定网址
   WebBrowser1.Navigate Combo1.Text
   End Sub

   Private Sub Combo1_KeyDown(KeyCode As Integer, Shift As Integer)
   Dim i As Long
   Dim existed As Boolean
   If KeyCode = 13 Then
   If Left(Combo1.Text, 7) <> “http://”Then
   Combo1.Text = “http://”+ Combo1.Text
   End If
   WebBrowser1.Navigate Combo1.Text
   For i = 0 To Combo1.ListCount - 1
   If Combo1.List(i) = Combo1.Text Then
   existed = True
   Exit For
   Else
   existed = False
   End If
   Next
   If Not existed Then
   Combo1.AddItem (Combo1.Text)
   End If
   End If
   End Sub

   Private Sub WebBrowser1_DownloadBegin()
   `下载开始时状态栏显示“Now Linking...”
   StatusBar1.SimpleText = “Now Linking...”
   End Sub

   Private Sub WebBrowser1_DownloadComplete()
   `下载完成时状态栏显示“Link Finished”
   StatusBar1.SimpleText = “Link Finished”
   ProgressBar1.Value = 0
   End Sub

   Private Sub WebBrowser1_ProgressChange(ByVal Progress As Long,
ByVal ProgressMax As Long)
   `下载进行时进度条变化
   If ProgressMax = 0 Then Exit Sub
   ProgressBar1.Max = ProgressMax
   If Progress <> -1 And Progress <= ProgressMax Then
   ProgressBar1.Value = Progress
   End If
   End Sub

   Private Sub WebBrowser1_TitleChange(ByVal Text As String)
   Combo1.Text = WebBrowser1.LocationURL
   End Sub