How to: Access the HTML Source in the Managed HTML Document Object Model

The DocumentStream and DocumentText properties on the WebBrowser control return the HTML of the current document as it existed when it was first displayed. However, if you modify the page using method and property calls such as AppendChild and InnerHtml, these changes will not appear when you call DocumentStream and DocumentText. To obtain the most up-to-date HTML source for the DOM, you must call the OuterHtml property on the HTML element.

The following procedure shows how to retrieve the dynamic source and display it in a separate shortcut menu.

Retrieving the dynamic source with the OuterHtml property

1. Create a new Windows Forms application. Start with a single Form, and call it Form1.

2. Host the WebBrowser control in your Windows Forms application, and name it WebBrowser1. For more information, see How to: Add Web Browser Capabilities to a Windows Forms Application.

3. Create a second Form in your application called CodeForm.

4. Add a RichTextBox control to CodeForm and set its Dock property to Fill.

5. Create a public property on CodeForm called Code.

   Public Property Code() As String
       Get
           If (RichTextBox1.Text IsNot Nothing) Then
               Code = RichTextBox1.Text
           Else
               Code = ""
           End If
       End Get
   
       Set(ByVal value As String)
           RichTextBox1.Text = value
       End Set
   End Property
   

   public string Code
   {
       get
       {
           if (richTextBox1.Text != null)
           {
               return (richTextBox1.Text);
           }
           else
           {
               return ("");
           }
       }
       set
       {
           richTextBox1.Text = value;
       }
   }
   

6. Add a Button control named Button1 to your Form, and monitor for the Click event. For details on monitoring events, see Consuming Events.

7. Add the following code to the Click event handler.

   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
       Dim elem As HtmlElement
   
       If (WebBrowser1.Document IsNot Nothing) Then
           Dim cf As New CodeForm()
           Dim elems As HtmlElementCollection = WebBrowser1.Document.GetElementsByTagName("HTML")
           If (elems.Count = 1) Then
               elem = elems(0)
               cf.Code = elem.OuterHtml
               cf.Show()
           End If
       End If
   End Sub
   

   private void button1_Click(object sender, EventArgs e)
   {
       HtmlElement elem;
   
       if (webBrowser1.Document != null)
       {
           CodeForm cf = new CodeForm();
           HtmlElementCollection elems = webBrowser1.Document.GetElementsByTagName("HTML");
           if (elems.Count == 1)
           {
               elem = elems[0];
               cf.Code = elem.OuterHtml;
               cf.Show();
           }
       }
   }
   

Robust Programming

Always test the value of Document before attempting to retrieve it. If the current page is not finished loading, Document or one or more of its child objects may not be initialized.

See Also

Reference

WebBrowser Control Overview

Other Resources

Using the Managed HTML Document Object Model