I will access the xml file on the Internet.
I found one but have not tried yet. How do you feel the idea from otaku?
http://www.dynamicdrive.com/forums/archive/index.php/t-9510.html


"Sam Hobbs" <samuel@s...> wrote in message 
news:OFhL6aBzIHA.3884@T......
> I assume you must do this over the internet; that you do not have local 
> access to the file, but it will help to know that for sure.
>
> If you can access the file locally, then Windows has a few functions that 
> will help.
>
> If you cannot access the file locally and must query over the internet, 
> then it is possible to query the last modified date and time of a file. If 
> you do that, then you don't need to read all the data just to determine if 
> it has changed. I forget how to do it; it is something I wanted to do a 
> couple of weeks ago but I can't find any of the samples I have of doing 
> it. I thought the data was part of the HTTP headers but I don't find it 
> there. Getting the last update time of a file over the internet is a very 
> common thing to do and I am sure we could find the answer easily if that 
> will help you. I just did not pursue it further when I was looking a 
> couple of weeks ago but I know I have samples somewhere in my system.
>
>
> "Elliot" <elliot_barclay@h...> wrote in message 
> news:223B8966-8D9E-46FE-89BD-C408E1741988@m......
>>I propose to write a C# program to get the content of a xml file.
>> However, that file may be modified after 10 seconds, 10 minutes or 10 
>> hours.
>> I think the algorithm of getting the content every 10 seconds to check 
>> whether it was chaged is too stupid, assuming there are 50,000 users 
>> running the program(cause a heavy workload for the web server, worse 
>> still it is unable to handle).
>> Certainly, less than 10-second delay is acceptable if real-time is 
>> impossible.
>> Please advise me a better algorithm.
>> Any idea would be appreciated.
>>
>
>
>