当我可以使用具有相同登录名的SQL Server Management Studio进行连接时，为什么我的应用程序不连接到SQL Server数据库？

Question

I realize this may be a difficult (impossible?) question to answer since I can't provide access to the actual server involved, but maybe there's something obvious I'm missing.

I have a C# Windows Forms application (.Net 4.5) that needs to connect to a SQL Server 2012 database. The connection string in App.config is as follows:

<connectionStrings>
  <add name="MyConnStr"
    connectionString="server=SERVERNAME.ads.lcl;database=MyDatabase;uid=MyUser;password=abcdefg1234567"
    providerName="AspNetSqlProvider" />

I am able to connect to and read from the database with SQL Server Management Studio using the same login and password (with SQL Server Authentication), so I know I have the server, database, uid, and password correctly specified in the connection string. But when I debug my program, I get an SQLException saying Cannot open database "MyDatabase" requested by the login. The login failed. Login failed for user 'MyUser'. Cannot open database "MyDatabase" requested by the login. The login failed. Login failed for user 'MyUser'.

I've done this a thousand times before, so I'm at a loss.

Here are the relevant sections of code, if it helps at all:

public static string MyConnStr
{
  get { return ConfigurationManager.ConnectionStrings["MyConnStr"].ConnectionString; }
}

public static int[] GetIntArrayFromDB(string query)
{
  DataTable dt = new DataTable();

  using (SqlConnection conn = new SqlConnection(MyConnStr))
  {
    using (SqlCommand cmd = new SqlCommand(query, conn))
    {
      using (SqlDataAdapter da = new SqlDataAdapter(cmd))
      {
        try
        {
          conn.Open();
          da.Fill(dt);
          conn.Close();
        }
        catch (SqlException)
        {
          return null;
        }
        finally
        {
          if (conn != null)
            conn.Dispose();
        }
      }
    }
  }

  int numRows = dt.Rows.Count;
  int[] retInt = new int[numRows];
  for (int i = 0; i < numRows; i++)
  {
    retInt[i] = Convert.ToInt32(dt.Rows[i][0]);
  }

  return retInt;
}

The query being passed to GetIntArrayFromDB() is "SELECT myID FROM myTable" . Any ideas?

UPDATE : The approach above with the named connection string is perfectly valid and works, if you don't misspell the connection string name in the config file. Sorry for this, I'm working on a sleep deficit. Thanks to everyone who offered suggestions!

Answer 1

I fixed it by changing the connection string specified in the App.config file to the following (note that the format of the connection string itself is the same, only the name is different):

<connectionStrings>
  <remove name="LocalSqlServer" />
  <add name="LocalSqlServer" connectionString="server=MyServer.ads.lcl;database=MyDatabase;uid=MyUser;password=abcdefg1234567"
    providerName="AspNetSqlProvider" />
</connectionStrings>

and by referencing the connection string in my C# code this way:

get
{
  return ConfigurationManager.ConnectionStrings[0].ConnectionString;
}

I do NOT understand why this made any difference! It seems quite bizarre.

Answer 2

If this is SQL Server, then your connection string should be something like the following

<add name="ConnectionStringName"
 connectionString="Data Source=DatabaseServer; Initial Catalog=DatabaseName; User ID=UserName; Password=YourPassword;"
 providerName="System.Data.SqlClient" />

Not sure if your example just isn't using the "Data Source" and "Initial Catalog" entries, but it looks like you're using "server" and "database" instead.

Answer 3

According to connectionstrings.com , your connection string should be in this format for SQL 2012:

Server=myServerAddress;Database=myDataBase;User Id=myUsername; Password=myPassword;

I've never used the format you are using, give this a shot.