Download a File - If exists in server - c#

Question

1.00/5 (1 vote)

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Hi ,
I have a code ,

C#

WebClient webClient = new WebClient();
webClient.DownloadFileAsync(new Uri("http://MySite.com/Desktop/Pics.png"), @"c:\users\Windows\desktop\DesktopsPics\Desktop.png");

My Program will download a .png picture every day as "Daily Pics" in a folder!
so , when user click on a button, if "Daily Pic" is already exists in server ,program download this file ...
I can do this with above code , but , if Pic.Png is not already exists in server , my program work with error !!!! (it download a .html file that is 404 not found" :)

so how can i download a file , if this file exist in a server ?!? :D

Thanks

Posted 11-Oct-13 8:39am

MohammadSina Karvandi

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Comments

joshrduncan2012 11-Oct-13 15:48pm

Your code looks correct. Are you asking how can a file be downloaded if it doesn't already exist on server?

MohammadSina Karvandi 11-Oct-13 15:53pm

yeah !!!

joshrduncan2012 11-Oct-13 16:09pm

You can't download something that doesn't exist.

MohammadSina Karvandi 11-Oct-13 16:25pm

so , can i check (if exit) download it ?

joshrduncan2012 11-Oct-13 16:28pm

Sure, you can check to see if the file exist and then download it if it does.

MohammadSina Karvandi 11-Oct-13 16:38pm

so , how do it :D ?

joshrduncan2012 11-Oct-13 16:40pm

I strongly suggest looking at how HttpWebRequest and HttpWebResponse commands work. Those would help in finding whether or not a file exists on the server. I'm not going to provide ready-made code without seeing some effort on your part first.

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Akinmade Bond · Accepted Answer · 2013-10-11T21:31:00

You can chrck if a file exitst on your web server.

C#

// create the request
HttpWebRequest request = WebRequest.Create(url);;

// instruct the server to return headers only
request.Method = "HEAD";

// make the connection
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

// get the status code
HttpStatusCode status = response.StatusCode;

Now you can check the responce codes against the ones listed here

HTTP_STATUS_NOT_FOUND is what you are looking for.

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