Handling different ConnectionStates before opening SqlConnection

Question

If you need to open a SqlConnection before issuing queries, can you simply handle all non-Open ConnectionStates in the same way? For example:

    if (connection.State != ConnectionState.Open)
    {
        connection.Open();
    }

I read somewhere that for ConnectionState.Broken the connection needs to be closed before its re-opened. Does anyone have experience with this? Thanks-

Answer 1

This isn't directly answering your question, but the best practice is to open and close a connection for every access to the database. ADO.NET connection pooling ensures that this performs well. It's particularly important to do this in server apps (e.g. ASP.NET), but I would do it even in a WinForms app that accesses the database directly.

Example:

using(SqlConnection connection = new SqlConnection(...))
{
   connection.Open();
   // ... do your stuff here

}  // Connection is disposed and closed here, even if an exception is thrown

In this way you never need to check the connection state when opening a connection.

Answer 2

http://msdn.microsoft.com/en-us/library/system.data.connectionstate.aspx

Broken connection state does need to be closed and reopened before eligible for continued use.

Edit: Unfortunately closing a closed connection will balk as well. You'll need to test the ConnectionState before acting on an unknown connection. Perhaps a short switch statement could do the trick.