Kirk Evans Blog

.NET From a Markup Perspective

Specify the HTML for a Windows Forms Web Browser Control

Mike asks: How do I specify the HTML for a web browser
control from a string?


The answer is fairly simple, yet I could not find a quick reference link
anywhere from a Google search. So, here is the set of steps to use the web
browser control and set the HTML for the control using a string.


There is no real magic: you just need 2 different libraries. The WebBrowser’s
Document
property returns an object representing the DOM for a web
page. However, this DOM does not exist until a page is loaded. Rather than load
a URL from a file, use about:blank for the URL to load a blank page.
When you call the Navigate method of the browser, the status text becomes
“Opening page about:blank…” When the document is finished loading, the status
text changes to “Done”. You can leverage this event to know that the browser is
finished loading the blank page, at which time the DOM is accessible.

If you are not using Visual Studio .NET, see the
Microsoft SDK documentation
for instructions on the Windows Forms
ActiveX Control Importer. This utility is used to create a Windows Forms
control based on the type library information in the ActiveX control.




  • Create a new Windows Form project.


  • Open the WYSIWYG designer for Form1. Right-click the Toolbox and choose Customize
    Toolbox…
    , and click the COM Components tab.


  • Browse the SYSTEM32 directory for shdocvw.dll.. Click OK to
    choose this DLL. Click OK to close the dialog. Your project references now
    shows a reference to AxShDocVw.dll.


  • Right-click the References tab and choose Add Reference… Click the
    COM tab. Click the Browse button. Navigate to the SYSTEM32 directory and choose
    mshtml.tlb
    . Click OK to close the dialog. Your project references
    now shows a reference to MSHTML.


  • From the Toolbox pane, drag an Explorer component onto Form1. name this control
    “browser” in the properties pane. Switch to the code view for the form and
    enter the following code for the form:


using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using mshtml;

namespace WindowsApplication2
{
public class Form1 : System.Windows.Forms.Form
{
private AxSHDocVw.AxWebBrowser browser;
private System.ComponentModel.Container components = null;

public Form1()
{
InitializeComponent();
string url = “about:blank”;
object o = System.Reflection.Missing.Value;
browser.Navigate ( url,ref o,ref o,ref o,ref o);
AxSHDocVw.DWebBrowserEvents2_StatusTextChangeEventHandler handler =
new AxSHDocVw.DWebBrowserEvents2_StatusTextChangeEventHandler
(this.browser_StatusTextChange);
browser.StatusTextChange += handler;
}

private void browser_StatusTextChange
(object sender, AxSHDocVw.DWebBrowserEvents2_StatusTextChangeEvent e)
{

mshtml.HTMLDocument doc = (mshtml.HTMLDocument)this.browser.Document;
doc.body.innerHTML = “<H1>foo</H1>”;

}

protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}

#region Windows Form Designer generated code

private void InitializeComponent()
{
System.Resources.ResourceManager resources = new
System.Resources.ResourceManager(typeof(Form1));
this.browser = new AxSHDocVw.AxWebBrowser();
((System.ComponentModel.ISupportInitialize)(this.browser)).BeginInit();
this.SuspendLayout();
//
// browser
//
this.browser.Enabled = true;
this.browser.Location = new System.Drawing.Point(16, 16);
this.browser.OcxState =
((System.Windows.Forms.AxHost.State)(resources.GetObject(“browser.OcxState”)));
this.browser.Size = new System.Drawing.Size(344, 224);
this.browser.TabIndex = 0;
//
// Form1
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(392, 302);
this.Controls.AddRange(new System.Windows.Forms.Control[] { this.browser});
this.Name = “Form1”;
this.Text = “Form1”;
((System.ComponentModel.ISupportInitialize)(this.browser)).EndInit();
this.ResumeLayout(false);

}
#endregion

[STAThread]
static void Main()
{
Application.Run(new Form1());
}

}
}

That’s all there is to it. Once the DOM is available, you have access to the
body of the HTMLDocument.