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Sunday, April 30, 2006

Opening URL from within the C# program

Use this function to retrieve path of default browser

/// <summary>

/// Reads path of default browser from registry

/// </summary>

/// <returns></returns>

private static string GetDefaultBrowserPath()


string key = @"htmlfile\shell\open\command";

RegistryKey registryKey =

Registry.ClassesRoot.OpenSubKey(key, false);

// get default browser path

return ((string) registryKey.GetValue(null, null)).Split('"')[1];


Opens URL in default browser from within the C# program.

string defaultBrowserPath = GetDefaultBrowserPath();



// launch default browser

Process.Start(defaultBrowserPath, "");


catch (Exception exp)




Opens URL in separate instance of default browser from within the C# program.

// open URL in separate instance of default browser

Process p = new Process();

p.StartInfo.FileName = GetDefaultBrowserPath();

p.StartInfo.Arguments = "";


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Cutriss said...

In theory, this should work, but it doesn't and it's not guaranteed to, because Firefox (at least) doesn't change the parameters for htmlfile in the registry (since the web is a lot more than just HTML). It modifies HTTP\shell\open\command though, and so does Internet Explorer, so if you want to use the default browser, you'd probably be better to look there. Opera uses this also, I believe.

Anonymous said...

Heh, I dont know why you guys making all the fuss....opening a web page in default browser is as simple as:


Check out msdn article:

Regards, Uros

Anonymous said...

How about someone decided that he wants to open all HTML files in notepad?

Better retrieve the default browser executable by the application that handles the http protocol (browser).
This can be found in:

btw, System.Diagnostics.Process.Start("http://.... indeed works perfect for opening an webpage.

Regards, JV.

Anonymous said...

Use System.Diagnostics.Process.Start(url) throw an error if the webrowser isnt opened already

Anonymous said...

System.Diagnostics.Process.Start(url) works without the browser beeing already opened(on my system). But this works only in .NET Framework 2.0 or higher. In version 1.1 throws Win32Exception with message "The system cannot find the file specified"

Anonymous said...

Visual Studio 2002 Using .NET 1.0
work flawlessy with/without browser running.

In fact it simply ask the OS to open an URL (NOT AN HTM(L) FILE!!!!), using the default behaviour, anything else is only f***ed up windows config and not a framework error/bug.


Ronny said...

There is a little bug here. It does not work with FireFox.

FireFox appears in the registry like this:
C:\PROGRA~1\MOZILL~1\FIREFOX.EXE -requestPending -osint -url "%1"
While ie like this:
"C:\Program Files\Internet Explorer\IEXPLORE.EXE" -nohome

The solution here (splitting by '"') does not work with FireFox.

Here is a solution:

private static string GetDefaultBrowserPath()
string key = @"http\shell\open\command";
Microsoft.Win32.RegistryKey registryKey = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(key, false);
// get default browser path
return StringToPath(((string)registryKey.GetValue(null, null)));

private static string StringToPath(string str)
char chPathEnd = ' ';
int diff = 0;
if (str[0] == '"')
chPathEnd = '"';
diff = 1;
for (int i = 1; i < str.Length; i++)
if (str[i] == chPathEnd)
return str.Substring(diff, i - diff);
return str;

Anonymous said...

If you want to open the url in Internet Explorer then you can use the next code:
System.Windows.Forms.WebBrowser IE1 = new System.Windows.Forms.WebBrowser();
IE1.Visible = true;
IE1.Navigate(new System.Uri(""));

Ganapati Bhat said...

Hi guys,

I have one problem related to this. I have one link in windows form. When i click on that it opens in IE7 browser. But when i go to same form and click on same link it opens that link in another tab of IE. It should not go to another tab. It should show same page which i opened 1st time. Here i am working on windows application. I have used System.Diagnostics.Process.Start method. I am facing this problem. Please help me in regarding this soon as possible.

Thanks in advance..

Anonymous said...

A major problem is opening an HTML with an anchor inside it: myfile.html#myanchor

This is when looking in the registry is very useful.