[dba-VB] C# Inheritance question

Use virtual method in the base class and override it in a derived class.

/SS-wp7

Sun, 22 Apr 2012 23:39:41 -0400 от jwcolby <jwcolby at colbyconsulting.com>:
> Yep, it seems that way, except that the while loop really is "common" to the
> base and the derived, 
> only the mErrFactory actually is different.  Having to carve the While loop
> out adds another 
> function to both base and derived.
> 
> John W. Colby
> Colby Consulting
> 
> Reality is what refuses to go away
> when you do not believe in it
> 
> On 4/22/2012 11:21 PM, Arthur Fuller wrote:
> > I know much  less than you about C# but what you want to do seems like a
> > violation of the intended design. Anything the base class needs should live
> > in it, not beneath it, no?
> >
> > A.
> >
> > On Sun, Apr 22, 2012 at 10:28 PM, jwcolby<jwcolby at colbyconsulting.com>wrote:
> >
> >> I have the following code which is in the base class:
> >>
> >>         protected bool mLoadFromSQLSrvr(string SQL)
> >>         {
> >>             try
> >>             {
> >>                 cnn = new SqlConnection(clsGlobals.**myConnection);
> >>                 cnn.Open();
> >>                 cmd = new SqlCommand(SQL, cnn);
> >>                 dr = cmd.ExecuteReader();
> >>                 while ((dr.Read()))
> >>                 {
> >>                     mErrFactory();
> >>                 }
> >>             }
> >>             catch (SqlException ex)
> >>             {
> >>
> >> The problem is that mErrFactory is different in the base and derived
> >> class.  Can this code be told to call the mErrFactory in the derived class?
> >>   Or do I need to just carve out the while loop and have this method just
> >> get the data reader something like this:
> >>
> >>         protected bool mSQLSrvrReader(string SQL)
> >>         {
> >>             try
> >>             {
> >>                 cnn = new SqlConnection(clsGlobals.**myConnection);
> >>                 cnn.Open();
> >>                 cmd = new SqlCommand(SQL, cnn);
> >>                 dr = cmd.ExecuteReader();
> >>                 return true;
> >>             }
> >>         }
> >>
> >>         private bool mLoadFromSQLSrvr(string SQL)
> >>         {
> >>
> >>                 if mSQLSrvrReader(strsql)
> >>                 {
> >>                 while ((dr.Read()))
> >>                 {
> >>                     mErrFactory();
> >>                 }
> >>
> >>                 }
> >>         }
> >>
> >> Then override mLoadFromSqlServer in the derived class?
> >>
> >> Since I know how to do the latter I am going there but I am wondering
> >> whether the base can be told to call an identically named method down in a
> >> derived class.  It seems unlikely but what do I know?
> >> --
> >> John W. Colby
> >> Colby Consulting
> >>
> >> Reality is what refuses to go away
> >> when you do not believe in it
> >>
> >> ______________________________**_________________
> >> dba-VB mailing list
> >> dba-VB at databaseadvisors.com
> >>
> http://databaseadvisors.com/**mailman/listinfo/dba-vb<http://databaseadvisors.com/mailman/listinfo/dba-vb>
> >> http://www.databaseadvisors.**com<http://www.databaseadvisors.com>
> >>
> >>
> >
> >
> 
> _______________________________________________
> dba-VB mailing list
> dba-VB at databaseadvisors.com
> http://databaseadvisors.com/mailman/listinfo/dba-vb
> http://www.databaseadvisors.com