Database Connection Error “file in use”

问题

I am using Visual Studio 2010 C# Express and SQL Server Management Studio with SQL Server 2012 I am getting an error when I try to connect a database to my Windows forms project.

"This file is in use.  Enter a new name or
close the file that is open in another program"

I poked around online to try to find a solution but none worked. So i decided to create a brand new database and a brand new project. But I still get the error!

here are the steps I use:

• First I connected to my locally hosted server
• then i right-clicked on Databases and selected New Database and named it school
• then i right clicked the tables folder on my new database and selected new table
• I added thes tables student, course, enrolled
• finally i threw some bogus entries into it

Now I jump over to VS

• I select New Project then Windows Forms Application and name it Registrar
• then i click add new data source
• select database in the Choose a data source type window
• then i select Dataset in the Choose a Database Model window
• then I click New Connection I change the DataSource to Microsoft SQL Server Database File browse to the DATA folder inside my 'SQLEXPRESS' folder and when i click the 'school.mdf' file i get the above error.

any help would be greatly appreciated.

回答1:

Your school.mdf is attached in your SQL Server 2012. You need to detach it.

Go to your SQL Server Management Studio, Right-Click on School, Tasks, Detach.

Unless it is detached, it will be in use by the the SQL Server Management Studio.

回答2:

You need To detach it. If you don't want to do that, select "Microsoft SQL Server" instead of "Microsoft SQL Server Database File". Express versions VB don't have Microsoft SQL Server option.

来源：https://stackoverflow.com/questions/13215172/database-connection-error-file-in-use