How to catch an exception where an interesting detail is in the error code?

Question

My database connection procedure may fail, for example, if the credentials are incorrect. In this case, a general OleDbException is generated with the ErrorCode code -2147217843 . The message gives an error, for example

No error message available, result code:
DB_SEC_E_AUTH_FAILED(0x80040E4D)

How do I catch this? Using error code -2147217843 seems a bit of a "magic number."

    Try
        mCon = New OleDbConnection(connectionString)
        mCon.Open()

    Catch ex As OleDbException
        If ex.ErrorCode = -2147217843 Then
            Engine.logger.Fatal("Invalid username and/or password", ex)
            Throw
        End If
    Catch ex As Exception
        Engine.logger.Fatal("Could not connect to the database", ex)
        Throw
    End Try

Answer 1

You can define error codes that interest you as int enum, which can be easily ported to int. I am not too familiar with VB, but I can show you in C # (should be easily converted):

public enum OleDbErrorCodes : int
{
    DB_SEC_E_AUTH_FAILED = -2147217843
}

Catch Enum int :

catch (System.Data.OleDb.OleDbException ex)
{
    if (ex.ErrorCode == (int)OleDbErrorCodes.DB_SEC_E_AUTH_FAILED)
    {
        // Log exception
    }
}