Use Visual C# to start the default Internet browser programmatically
This article shows how to start the default Internet browser by using Visual C#.
Original product version: Visual Studio
Original KB number: 305703
Note
- This article refers to the Microsoft .NET Framework Class Library namespace
System.Diagnostics
. - For a Visual C++ .NET version of this article, see How to programmatically start the default Internet browser by using Visual C++.
Specify the URL, FTP, or file to open
You can specify a URL, a file, or a File Transfer Protocol (FTP) address. All three of these assignments are valid:
string target= "http://www.microsoft.com";
string target = "ftp://ftp.microsoft.com";
string target = "C:\\Program Files\\Microsoft Visual Studio\\INSTALL.HTM";
Use the Process class Start method to start the browser
The Process
class contains a static Start
method. Because it's a static method, you can call Start
without having an instance of a Process
class.
System.Diagnostics.Process.Start(target);
For more information about the Process
class, see Process Class.
Provide exception handling
Because you take advantage of the default UseShellExecute
property when you call the Start
method, you don't have to explicitly query the registry to determine which browser is the default. However, if you use this approach on a computer that doesn't have a browser installed, an exception occurs. This exception must be caught so that the appropriate action can be taken.
This example explicitly trap for an error that's generated when the necessary registry key isn't found and indicates that no browser is installed. Additionally, a general exception handler is provided for other errors that may occur. The try...catch
block is demonstrated in the complete code listing.
Complete code sample
string target= "http://www.microsoft.com";
//Use no more than one assignment when you test this code.
//string target = "ftp://ftp.microsoft.com";
//string target = "C:\\Program Files\\Microsoft Visual Studio\\INSTALL.HTM";
try
{
System.Diagnostics.Process.Start(target);
}
catch (System.ComponentModel.Win32Exception noBrowser)
{
if (noBrowser.ErrorCode==-2147467259)
MessageBox.Show(noBrowser.Message);
}
catch (System.Exception other)
{
MessageBox.Show(other.Message);
}
Troubleshooting
This code is highly dependent on the application-file type associations in the HKEY_CLASSES_ROOT (HKCR) hive of the registry. It can lead to unexpected results and exceptions if the registry is damaged. Additionally, file types and extensions may be associated with applications other than the browser. For example, HTM or HTML files may be associated with Web development software instead of the browser.
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