Question

I am accessing a service based database by using the following connection string

static string appath = Library_Records.Program.app_path;

string connectionstring = @"Data Source=.\SQLEXPRESS;AttachDbFilename=appath;Integrated Security = true;User Instance = True";
connection = new SqlConnection(connectionstring);

 static string dbfiles = null;
 internal static string app_path
 {
     get { return dbfiles = "|Datadirectory|\\5700.mdf"; }
 }

Library_Records:namespace, Program is the class name containing Main()

When I call connection.Open(), it gives the following error

An attempt to attach an auto-named database for file appath failed. A
database with the same name exists, or specified file cannot be
opened, or it is located on UNC share.

5700 is my database with .mdf extension. How to rectify this problem?

Answer 1

Variables are never automatically replaced with values in strings, so AttachDbFilename=appath; will not work.

You should do something like:

string connectionstring = 
    string.Format(@"Data Source=.\SQLEXPRESS;AttachDbFilename={0};Integrated Security=True;User Instance=True", appath);

connection = new SqlConnection(connectionstring);