CSharpDelegates.cs

// This is all pseudo code, never tested, just to give a quick idea of a delegate

// Just like you use the "class" keyword to define the characteristic of an object, you can use
// "delegate" to define the characteristic of a method.
public delegate void PerformDatabaseAction(SqlConnection sqlConn);

public static class DatabaseHelpers
{
  public static void DoDatabaseAction(PerformDatabaseAction theDbAction)
  {
    var sqlConnection = new SqlConnection("somesqlconnectionstring");
    theDbAction(sqlConnection);
    sqlConnection.Dispose();
  }
}

public class ChargePointDataRetriever
{
  private List<ChargePoint> _data;
  
  private void GetData(SqlConnection conn)
  {
      var result = conn.ExecuteQuery("SELECT * FROM ChargePoint");
      
      _data = result.ToArray();
  }
  
  public void Start()
  {
    // The parameter of the function is the PerformDatabaseAction delegate. Because the GetData method above matches the signature of
    // the delegate (void as return and SqlConnection as param), we can just pass the method as parameter.
    PerformDatabaseAction theDbAction = GetData;
    
    DatabaseHelpers.DoDatabaseAction(theDbAction);
    
    Console.PrintLine(_data);
  }
}