Most of the web applications generate data dynamically and send it using the Query String Parameter or Form Post Parameter to subsequent requests. For example, the current user session ID, connection string, or parameter values to the method called are some of the dynamic data. Web tests can identify and detect these dynamic parameters from the request response and then bind it to the other requests. This process is also known as Promoting Dynamic Parameters.
Dynamic parameters are automatically detected by the web test after the web test recording is stopped. Visual studio web testing keeps track of the requests and finds the hard-coded values, which can be replaced by dynamic parameters. The advantage of using dynamic parameters is that we can pass different values to the parameter and verify the test. The other reason is to avoid the playback failure. If we don't promote the dynamic parameters, the playback of the test may fail as the parameter values...