Error: Sequence contains more than one element

I am getting the following err开发者_Go百科or on production server. It works well on localhost.

Error: Sequence contains more than one element

That is an InvalidOperationException thrown by the Single method.

This method is supposed to return only one element, and your query is returning more than one, you have to check the criteria you use on your query.

It will also throw an exception if it doesn't find an element. You can use SingleOrDefault() method to return null (or default value, i.e. 0 for int) if there are no records.

If you are expecting multiple elements but just one the first one, you can use First instead of Single or FirstOrDefault.