一.问题的提出
偶然发现，Winform里的WebBrowser和IE实际安装的版本似乎并不同步，很有趣！
下面有张图，里面一个窗口是用IE9打开某网站，另一个窗口是用Winform+WebBrowser打开同样的网站，有意思的事情出现了。
在IE9窗口中，这个网站左边菜单树无法显示，原因是IE9使用的技术较新，而网站使用的技术较旧，未能及时同步更新到支持IE9所致。该如何办呢？
微软在IE9中提供一个兼容性视图功能，只要一点击兼容性视图就可以兼容旧版本浏览器的网站。
引用MSDN “To overcome potential compatibility issues, Internet Explorer supports a feature called Compatibility View that allows users to display troublesome pages in IE7 mode. “ URL: http://msdn.microsoft.com/en-us/library/dd567845(v=VS.85).aspx
也就是说，这个兼容模式就是IE7的模式。
又查了些ms资料，发现这个兼容性视图在IE8时首次引入，在IE9，IE10中都将继续支持。
再翻回来看Winform+WebBrowser这个窗口，它打开同样的网站却能显示左边菜单树，这样看来，似乎WebBrowser不用设置就默认自动打开了兼容性视图模式。
现在就去仔细查一下权威资料，核实一下两个问题：
1.Webbrowser与IE到底是什么关系？是否确实用ie内核, 是否本质上和360安全浏览器，傲游浏览器和腾讯TT等IE内核浏览器相同。
2.Webbrowser是否使用兼容浏览模式，以及这个模式是否能改？
二.查询结果
1.webbrowser调用的就是本机IE9，并且webbrowser默认就是运行在IE7 mode下，除非你改变它.
发现一个msdn的帖子，明确表示webbrowser调用的就是本机IE9，并且webbrowser默认就是运行在IE7 mode下，除非你改变它。
How to make c# WebBrowser equivalent to IE browser
http://social.msdn.microsoft.com/Forums/en/winforms/thread/2ed65b9d-c601-4ca8-bde1-64584fc87515
摘几句：
Wow first post with such bold claim without any source backing up. You probably should read the IE SDK (the manual you need to read if you want to use the webbrowser control) or dig through the IE programming forums (that's the place others often go when they are stuck on IE programming) if you want to use the webbrowser control.
Webbrowser is a wrapper around IE APIs. There is no such thing as multiple versions of IE coexisting on the same computer. You will always get the one and only version of IE installed on the computer from webbrowser control.
There are many, many documented setting differences between default IE and webbrowser. Basically you don't have to opt out new features in webbrowser that may break your app (the Visual Studio team learned a hard lesson here, when IE8 breaks Visual Studio's wizards) , you have to write code to opt in, unless the improvement is security related. That means the webbrowser will run in IE7 mode unless you change the mode in feature control.
Note some web site declare their requirement of IE7 or IE8 mode. It may not be wise to force the IE9 mode.
2.微软新闻组的一个帖子，Webbrowser Control without IE，里面明确提到，不装IE，无法用webbrowser.
http://groups.google.com/group/microsoft.public.vb.controls/browse_thread/thread/7575bd25e0730ded/aa40f3dfc799407d?lnk=gst&q=WebBrowser+ie#aa40f3dfc799407d
IE must be installed on the machine for you to use Webbrowser Control.
Internet Explorer MUST be installed to use the WebBrowser control. There are simply no ifs, ands, or buts about it. How can you expect to use IE functionality if IE is not installed?
3.如何设置WebBrowser在IE9 mode下工作呢？
答曰：需要修改注册表，具体看下面4，5，6，尤其6最全面，可以光看6。
4.WPF webbrowser control using IE7 instead of IE9
http://social.msdn.microsoft.com/Forums/en-US/iewebdevelopment/thread/4431908e-1869-4435-bcea-a3ec0820edfb
摘抄几句：
How do I make it so the WPF WebBrowser control will use IE9 as the browser engine instead of IE7?
I have some HTML that is rendering differently in the WebBrowser control than in the IE9 browser. When I run the following javascript in the WebBrowser, the result is "7". as in IE7.
I found an article by Rick Strahl that describes registry settings that will get the WebBrowser to use IE9. But I would like to avoid that. And I am interested to know how IE7 comes about being used.http://www.west-wind.com/weblog/posts/2011/May/21/Web-Browser-Control-Specifying-the-IE-Version
回答：You want to avoid the only documented way to set document compatibility mode for webbrowser hosts? Why?
5.WebBrowser and CSS3 ?
http://social.msdn.microsoft.com/Forums/en-AU/winforms/thread/1b656af7-bda9-47d9-8f9a-1d886d3688ca
Web browser control by default runs in compatibility mode unless you set the feature browser emulation registry key. The fact that IE9 is able to render CSS3 correctly and browser control is not seems to suggest browser control is not running in IE9 standards mode.
You'll need to set Browser emulation feature key (FEATURE_BROWSER_EMULATION) described at this link http://msdn.microsoft.com/en-us/library/ee330730%28v=vs.85%29.aspx
You can use 9000 value, unless you want to force IE 9 standards mode for all pages. In case of later, you need to use 9999.
hklm
If hklm and 64bit machine used, you need to check is Wow6432Node needs to be changed.
And finally you need to add process name hosting browser control as value name in the registry key.
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION]
"prevhost.exe"=dword:00001f40
"sllauncher.exe"=dword:00001f40
"WindowsFormsApplication1.exe"=dword:0000270f
6.Web Browser Control – Specifying the IE Version
http://www.west-wind.com/weblog/posts/2011/May/21/Web-Browser-Control-Specifying-the-IE-Version
I use the Internet Explorer Web Browser Control in a lot of my applications to display document type layout. HTML happens to be one of the most common document formats and displaying data in this format – even in desktop applications, is often way easier than using normal desktop technologies.
One issue the Web Browser Control has that it’s perpetually stuck in IE 7 rendering mode by default. Even though IE 8 and now 9 have significantly upgraded the IE rendering engine to be more CSS and HTML compliant by default the Web Browser control will have none of it. IE 9 in particular – with its much improved CSS support and basic HTML 5 support is a big improvement and even though the IE control uses some of IE’s internal rendering technology it’s still stuck in the old IE 7 rendering by default.
This applies whether you’re using the Web Browser control in a WPF application, a WinForms app, a FoxPro or VB classic application using the ActiveX control. Behind the scenes all these UI platforms use the COM interfaces and so you’re stuck by those same rules.
Feature Delegation via Registry Hacks
Fortunately starting with Internet Explore 8 and later there’s a fix for this problem via a registry setting. You can specify a registry key to specify which rendering mode and version of IE should be used by that application. These are not global mind you – they have to be enabled for each application individually.
There are two different sets of keys for 32 bit and 64 bit applications.
32 bit:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION
Value Key: yourapplication.exe
64 bit:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION
Value Key: yourapplication.exe
The value to set this key to is (taken from MSDN here) as decimal values:
9999 (0x270F)
Internet Explorer 9. Webpages are displayed in IE9 Standards mode, regardless of the !DOCTYPE directive.
9000 (0x2328)
Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode.
8888 (0x22B8)
Webpages are displayed in IE8 Standards mode, regardless of the !DOCTYPE directive.
8000 (0x1F40)
Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode.
7000 (0x1B58)
Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode.
ok, 言尽至此，无话可说了！