What is the difference between response.Close, response.End, and response.Flush?

response.Close, response.End, and response.Flush are all methods used to end the server’s response to the client, but there are some differences between them.

1. response.Close is a method of the HttpResponse object that is used to close the connection with the client. It sends any remaining response data to the client and then closes the connection. This method is not commonly used in general, with response.End being more frequently used in ASP.NET.
2. The method response.End, also a method of the HttpResponse object, is used to immediately stop the current page’s execution and send the complete response to the client. This method will throw a ThreadAbortException exception, which can be caught and handled using a try-catch block. Once the response.End method is executed, no further code will run.
3. response.Flush: This method is used to send the content in the response buffer to the client. It forcibly sends the data in the buffer to the client without waiting for the buffer to be filled or reach a certain time interval. This method is commonly used in situations where data needs to be sent to the client in real-time, such as real-time log or progress bar updates.

In summary, both response.Close and response.Flush are used to send a response to the client, while the response.End method immediately ends the current page’s execution and sends a complete response to the client.