I could be wrong on this, but I don't think you can add a field to an open dataset. That said, I'm thinking you could use dataset.disablecontrols, then close it, then something along the lines of dataset.fields.create, save the field, re-enable the controls, and the open the dataset again. You may need to refresh the grid's reading the field list again too, but I suspect that may happen on dataset.open.
If loading/saving from file turns out to be required while the dataset is "closed" (it's been a while since I've used that), the fields not matching up will likely cause grief. If that turns out to be the case, perhaps you could clone the dataset object after saving it to file, THEN add the field to the new clone, savetofile as a blank / no-data dataset, and have a routine that pipes that data from Dataset1 to Dataset2, with appropriate blank/null/default data in whatever "NewField" ends up being. This is all just wild subjective guessing however. <g> Just some ideas for you to bounce around. Either way, please do let us know how it turns out for you, and what ends up working, K? : ) ...btw, this a perfect example of the kind of "magic" users never fully appreciate the back-end of. ; ) - C - Alan Colburn wrote: > Hi folks -- > > Can anyone show me how to add fields at runtime to an open, already existing > client data set being stored via the SaveToFile method? I'd like a user to > be able to see a DBGrid and, with the click of a menu item, add a new > field--without losing anything already in the DB. > > Thanks, as always -- Al > > _______________________________________________ > Delphi-DB mailing list > Delphi-DB@elists.org > http://www.elists.org/mailman/listinfo/delphi-db > > _______________________________________________ Delphi-DB mailing list Delphi-DB@elists.org http://www.elists.org/mailman/listinfo/delphi-db
