How to create a console application in C # for the efficient use of IDisposable resources?

Question

Here I suggested (very simplifiedly illustrate the problem space) for a C # console application. Database connections implement IDisposable, and this solution does not allow usingdatabase objects to be connected. Can someone suggest a more proper structure for a console application? This is a problem that I need to solve often.

class Program 
{
    SQLiteConnection sourceConnection;
    SQLiteConnection destinationConnection;

    static void Main(string[] args)
    {
        Program shell = new Program();

        // get connection strings from command line arguments
        string sourceConnectionString = shell.getConnectionString(args);
        string destinationConnectionString = shell.getConnectionString(args);

        // call non-static methods that use
        shell.setUpConnections(sourceConnectionString, destinationConnectionString);

        shell.doDatabaseWork();
    }

    private void setUpConnections(string sourceConnectionString, string destinationConnectionString)
    {
        sourceConnection = new SQLiteConnection(sourceConnectionString);
        destinationConnection = new SQLiteConnection(destinationConnectionString);
    }

    private void doDatabaseWork()
    {
        // use the connections here
    }
}

Edit:

Some people cannot understand why I want them to be member variables. Here is my use case (a bit psuedocoded) about what doDatabaseWork will do:

foreach (Row sourceRow in DBResultSet)
{
  string sourceXml = sourceRow.Columns["MyColumnName"].Value;
  string destinationXML = transformUsingXSLT(sourceXml);
  writeToDestination(destinationXml);
}

See how I want these connections to open up for the life of this cycle?

Answer 1

, Program. - . SqlConnections - , , . , :

class ProgramCore : IDisposable
{
    internal ProgramCore(string sourceConnectionString, string destinationConnectionString)
    {
        setUpConnections(sourceConnectionString, destinationConnectionString);
    }

    internal void Execute()
    {
        // do whatever you want
        doDatabaseWork();
        // do whatever you want
    }

    public void Dispose()
    {
        if (_sourceConnection != null)
            _sourceConnection.Dispose();
        if (_destinationConnection != null)
            _destinationConnection.Dispose();
    }

    private void setUpConnections(string sourceConnectionString, string destinationConnectionString)
    {
        _sourceConnection = new SQLiteConnection(sourceConnectionString);
        _destinationConnection = new SQLiteConnection(destinationConnectionString);
    }

    private void doDatabaseWork()
    {
        // use the connections here
    }

    private SQLiteConnection _sourceConnection;
    private SQLiteConnection _destinationConnection;
}

class Program
{
    static void Main(string[] args)
    {
        // get connection strings from command line arguments
        string sourceConnectionString = GetConnectionString(args);
        string destinationConnectionString = GetConnectionString(args);

        using (ProgramCore core = new ProgramCore(sourceConnectionString, destinationConnectionString))
        {
            core.Execute();
        }
    }

    static string GetConnectionString(string[] args)
    {
        // provide parsing here
    }
}

Answer 2

, IDisposable.

DB.

IDisposable.Dispose .

, , :

public class DBWrapper : IDisposable
{
    public SqlConnection Connection1 { get; set; }
    public SqlConnection Connection2 { get; set; }

    public DBWrapper()
    {
        Connection1 = new SqlConnection();
        Connection1.Open();
        Connection2 = new SqlConnection();
        Connection2.Open();
    }
    public void DoWork()
    {
        // Make your DB Calls here
    }

    public void Dispose()
    {
        if (Connection1 != null)
        {
            Connection1.Dispose();
        }
        if (Connection2 != null)
        {
            Connection2.Dispose();
        }
    }
}

, :

class Program
{
    static void Main(string[] args)
    {
        using (DBWrapper wrapper = new DBWrapper())
        {
            wrapper.DoWork();
        }
    }
}

Answer 3

- . try {} ?

static void Main(string[] args)
{
    Program shell = new Program();

    // get connection strings from command line arguments
    string sourceConnectionString = shell.getConnectionString(args);
    string destinationConnectionString = shell.getConnectionString(args);

    // call non-static methods that use
    shell.setUpConnections(sourceConnectionString, destinationConnectionString);
    try
    {
      shell.doDatabaseWork();
    }
    finally
    {
      if(sourceConnection != null)
        sourceConnection.Dispose();
      if(destinationConnection != null)
        destinationConnection.Dispose();
    }
}

Answer 4

, , imho. , IDisposable , .

using() {}.

? ? .net, Connection . , , , .

, , .

class Program 
{
    static void Main(string[] args)
    {
        DBWorker worker = new DBWorker();
        worker.DoDatabaseWork();
    }
}

public class DBWorker 
{

    private void DoDatabaseWork()
    {
        using (SQLiteConnection sourceDB = new SQLiteConnection( GetConnectionString() ))
        {
            sourceDB.Open();
            using (SQLiteConnection destDB = new SQLiteConnection( GetConnectionString() ))
            {
                destDB.Open();
            }
        }
    }

}

Answer 5

Hmm, I see no one mentioned it like that. You do not need to have variables that are used usinglocally in the declaration .

class Program 
{
    SQLiteConnection sourceConnection;
    SQLiteConnection destinationConnection;

    static void Main(string[] args)
    {
        Program shell = new Program();

        // get connection strings from command line arguments
        string sourceConnectionString = shell.getConnectionString(args);
        string destinationConnectionString = shell.getConnectionString(args);

        using (sourceConnection = new SQLiteConnection(sourceConnectionString))
        using (destinationConnection = new SQLiteConnection(destinationConnectionString))
        {
            shell.doDatabaseWork();
        }
    }

    private void doDatabaseWork()
    {
        // use the connections here
    }
}