Little issue connecting to SQL Server 2008 with C# 2010

Question

I'm trying to connect an application in WPF with a database and when I select the database I want this message is shown:

[filename].mdf is currently in use. Write a new name or close the other program that's using the file.

The problem is that I don't have any other program using the DB at that time.

Can anyone tell me why is this happening? Thanks in advance.

Answer 1

How, pray, are you connecting to the database? Do not open the file directly. You need to connect to SQL Server.

You need a connection string, a typical connection string looks like this:

Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;

The code should look something like this:

SqlConnection conn = new SqlConnection(
        "Data Source=(local);Initial Catalog=Northwind;Integrated Security=SSPI");

    SqlDataReader rdr = null;

    try
    {
        // 2. Open the connection
        conn.Open();

        // 3. Pass the connection to a command object
        SqlCommand cmd = new SqlCommand("select * from Customers", conn);

        //
        // 4. Use the connection
        //

        // get query results
        rdr = cmd.ExecuteReader();

        // print the CustomerID of each record
        while (rdr.Read())
        {
            Console.WriteLine(rdr[0]);
        }
    }
    finally
    {
        // close the reader
        if (rdr != null)
        {
            rdr.Close();
        }

        // 5. Close the connection
        if (conn != null)
        {
            conn.Close();
        }
    }

Example from: http://www.csharp-station.com/Tutorials/AdoDotNet/Lesson02.aspx