For example, I am searching for “read excel file in asp.net C#”
I will get results which match “C#” and “excel file” but has nothing with ASP.NET. Those results are returned because the file extension of the page is .asp. or .net
It’s there any ways to instruct Google to ignore the file extensions?
What’s actually happening is that it’s finding the term in the URL. There are two things you can do, and you’ll probably want to do both.
First off, Google sees a period as a word separator, so you’ll want to put “asp.net” in quotation marks so it will know it’s just one term. Secondly, you’ll want to shut off looking in the URL, which can be done by adding "allintext: " to the beginning of your search.
Thus, the full search terms for what you want to do are: allintext: read excel file in “asp.net” C#. I got a good response on the first listing.
EDIT: For more information about Google search operators, try this site.
Try using the filetype: modifier:
“read excel file in asp.net C#” -filetype:aspx -filetype:net
gives me only two results…one of which is this thread. It seems to filter out a lot.
-D/a
I’ve given up using “asp.net” in search terms. I get a lot of asp pages too. C# is nearly synonymous with “asp.net” so using that is redundant.
I think that that is only going to return pages that contain the exact phrase “read excel file in asp.net C#”. I do not that is what the OP wants. I am rather surprised you found any at all apart from this thread. BigT seems to have the answer, anyway.
True… Take the quotes off, though, and maybe it’ll be helpful. But, as you point out, there’s a working solution posted. So the rest is educational. 
-D/a