How to open in default browser in C#

You can just write

System.Diagnostics.Process.Start("http://google.com");

EDIT: The WebBrowser control is an embedded copy of IE.
Therefore, any links inside of it will open in IE.

To change this behavior, you can handle the Navigating event.

For those finding this question in dotnet core. I found a solution here

Code:

private void OpenUrl(string url)
{
    try
    {
        Process.Start(url);
    }
    catch
    {
        // hack because of this: https://github.com/dotnet/corefx/issues/10361
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
        {
            url = url.Replace("&", "^&");
            Process.Start(new ProcessStartInfo("cmd", $"/c start {url}") { CreateNoWindow = true });
        }
        else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
        {
            Process.Start("xdg-open", url);
        }
        else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
        {
            Process.Start("open", url);
        }
        else
        {
            throw;
        }
    }
}

public static void GoToSite(string url)
{
     System.Diagnostics.Process.Start(url);
}

that should solve your problem