Error in C# Code Backup option

1. The file is being used by some process. I believe the database is still attached to Sql Server.
2. Use Process Explorer tool from Sys Internal to find out the program using this file.
3. Why don't you use SQL back tool to backup the database?

Check out What happens during a live SQL Server backup?

If you still want to backup or make copy of ldf mdf files then you can perform these steps: 1. Detach database

USE MASTER;
GO
-- Take database in single user mode -- if you are facing errors
-- This may terminate your active transactions for database
ALTER DATABASE DatabaseName
SET SINGLE_USER
WITH ROLLBACK IMMEDIATE;
GO
-- Detach DB
EXEC MASTER.dbo.sp_detach_db @dbname = N'DatabaseName'

2. Open Windows Explorer go to the the folder where ldf and mdf files are and then copy the file manually.

3. Reattach the database:

USE [master]
    GO
    CREATE DATABASE [DatabaseName] ON
    ( FILENAME = N’C:\Data\DataBase_Data.mdf’ ),
    ( FILENAME = N’C:\Data\Database_Log.ldf’ )
    FOR ATTACH
    GO
    IF EXISTS ( SELECT name FROM master.sys.databases sd  
    WHERE name = N’DataBaseName’ AND SUSER_SNAME(sd.owner_sid) = SUSER_SNAME() )
        EXEC [AdventureWorks].dbo.sp_changedbowner @loginame=N’sa’,@map=false

4. If you want to do it programatically, then you can execute the command given in step 1,2,3 using ADO.NET and the use c# file copy command to copy the file.

Download Process Explorer and run the program.

Option 1:

Click the Find menu, and choose Find Handle or DLL...

Type the file name (in your case JDB.mdf)

After typing the search phrase, click the Search button

Once you know what process the file has locked you, need to close that process (by closing that program). Another option is to use KILL in the process explorer terminating that process.

Option 2:

From the error message, the .mdf file has already been attached to an instance of an SQL Server. If you have multiple instances running, make sure it is detached from any other instance.