Pause Download & Resume (Merge The Existing File)

I'm making a downloader using C#, I want to add a feature of Pause & Resume download, I googled & implemented the suggestions but it didn't work for me; was resuming from the cor开发者_如何学JAVArect position but had problem merging with the downloaded part. I tested it by downloading a video file but after pausing the download & starting it again the result file played for while (it played the portion which it downloaded before pausing but not the portion after pausing).

How can i merge the 2 portions successfully.

We can't figure out what's wrong with your code, because we can't see your code (it's not always enough to post the source using which you made your own code).

Either way, you can try this: Create a file with some easy to spot bit pattern (like 0101010101010101...) using some hex-editor, and try to see where it breaks. If, for instance, the second part of the download keeps running over the few last bits of the first part, that would give you some clue.