The UserAgent property retrieves the current user-agent
string used by this browser instance. This value is the exact
string sent in the user-agent header of outgoing HTTP requests
and is determined by the underlying Microsoft Edge WebView2
runtime unless explicitly changed. The returned value can be used for informational purposes,
such as logging the client identity or displaying diagnostic
information to the user. It is also useful if your application
needs to preserve the default user-agent string before setting
a custom one.
Setting this property changes the string that will be sent
in the user-agent header for all subsequent HTTP requests made by this browser
instance. This property should always be used to modify the user-agent header
value; you should not set the header directly using the SetHeader
method.
Applications may want to override the default user-agent in several
scenarios:
- Requesting a mobile or tablet version of a site by providing a
user-agent string that identifies as a mobile browser.
- Emulating a different browser for testing purposes.
- Including custom product tokens identifying the host application to the server.
The general format of a user-agent string follows the conventions described
in RFC 9110:
User-Agent: product / version (comment) [ product / version ... ]
For example, a typical user-agent string might look like:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36 Edg/140.0.0.0
This value is global to the control instance. Once changed, it will remain in
effect until explicitly reset or until the browser control is destroyed.
When setting a custom user-agent value, developers should ensure it is a
syntactically valid string. Some websites may reject requests or provide
degraded functionality if the value is malformed or omits key tokens.
If you want to change the user-agent string to identify your
application, it is recommended that you append your application name
and version to the default value.