InvalidOperationException The connection was not closed. The connection's current state is open

Question

Why does this code throw an Invalid Operation Exception?

private SqlCommand cmd; // initialized in the class constructor

public void End(string spSendEventNotificationEmail) {
  try {
    cmd.CommandText = spSendEventNotificationEmail;
    cmd.Parameters.Clear();
    cmd.Parameters.Add("@packetID", SqlDbType.Int).Value = _packetID;
    cmd.Parameters.Add("@statusID", SqlDbType.Int).Value = _statusID;
    cmd.Parameters.Add("@website", SqlDbType.NVarChar, 100).Value = Tools.NextStep;
    cmd.Connection.Open();
    cmd.ExecuteNonQuery();
  } finally {
    cmd.Connection.Close();
    cmd.Parameters.Clear();
    cmd.Dispose();
  }
  endCall = true;
}

Answer 1

You're trying to open a connection which is already open, this results in exception.

Solution 1 (recommended):

Inspect your code, check all the parts where cmd.Connection connection is opened and ensure that it's always closed properly.

Solution 2 (quick'n'dirty fix):

before line

cmd.Connection.Open();

add the following check/cleanup code:

if (cmd.Connection.State == ConnectionState.Open)
{
    cmd.Connection.Close();
}