Quote
Alin Flaider wrote:
> Steve Zimmelman wrote:
> > If you use the ClientDataSet, then you can build indexes on those keys. But
> > you need the CS version of Delphi 3. Otherwise, yes, you need to run the
> > query again with the an Order By clause.
> > Mauricio Korbman wrote in message <69qjn5$f...@forums.borland.com>...
> > >I have a dbgrid that gets its data from a tquery. I want to be able to
> > >resort the grid based on the user clicking a column on it. Do I need to
> > >issue a new query every time the user clicks on a col. or is there a way to
> > >resort the records in memory?????
> Or you can batch copy your query dataset to a temporary table, add a
> primary and several secondary indexes for each sort case, then link it
> to your grid. This works with any flavour of Delphi.
> Servus, Alin
> __________________________________________________________________
> Alin Flaider mailto:aflai...@datalog.ro
> Delphi home page: http://www.datalog.ro/delphi/delphires.html
> Datalog Computers, http://www.datalog.ro, tel/fax +40 65 169867
Try this generic function: (It uses Infopower wwDBGrid and wwQuery
You can modify to use standard DB controls.)
unit uSort;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs, Menus, Grids, Wwdbigrd, Wwdbgrid, DB, DBTables, Wwquery,
Wwdatsrc,ExtCtrls, DBCtrls, StdCtrls;
Type
TGridSort = Class(TObject)
Private
{Private Declarations}
Public
{Public Declarations}
procedure GridSort(Sender : TObject; Direction : String);
end;
implementation
procedure TGridSort.GridSort(Sender : TObject; Direction : String);
var
GridPos : integer;
sList : TStringList;
sSql : String;
sStr : String;
strIndex,
strCount : integer;
sSort : String;
sDataSet : TWWQuery;
OriginalSQL : String;
position : integer;
intLength : Integer;
bIsNull : Boolean;
begin
GridPos := TwwDBGrid(Sender).getactiveCol;
if ((TwwDBGrid(Sender).fields[GridPos-1].dataType <> ftMemo) and
(TwwDBGrid(Sender).fields[GridPos-1].dataType <> ftBlob) and
(TwwDBGrid(Sender).fields[GridPos-1].dataType <> ftgraphic)) then
Begin
OriginalSQL :=
UpperCase(twwquery(twwdbgrid(sender).datasource.dataset).sql.text);
if Pos('ISNULL', OriginalSQL) > 0 then
bIsNull := True;
{Pos(Substr: string; S: string): Integer;}
Position := pos('ORDER',OriginalSQL);
intLength := Length(OriginalSQL);
{Delete(var S: string; Index, Count:Integer);}
Delete(OriginalSQL,Position,(intLength-Position)-1);
if UpperCase(Direction) = 'ASCENDING' then
sSort := ' order by %s asc'
Else if UpperCase(Direction) = 'DESCENDING' then
sSort := ' order by %s desc';
slist := Tstringlist.create;
sDataSet := TWWQuery(TwwDBGrid(Sender).DataSource.DataSet);
sDataSet.getfieldnames(sList);
sStr := sList.strings[GridPos - 1];
sSql := sDataSet.sql.text;
strIndex := pos(sStr, sSql);
if strIndex <> 0 then
begin //needed for select * type sql statements
StrCount := strIndex;
if not bisNull then
begin
repeat dec(strIndex) until sSQL[strIndex] = ' ';
strCount := (strCount + length(sStr)) - StrIndex;
end;
with sDataSet do begin
close;
if bisNull then
sql.text := originalSQL + Format(sSort,[sStr])
else
sql.text := originalSQL +
format(sSort,[copy(sSQL,strIndex,StrCount)]);
open;
end; //with q1
end // if..else statement
else begin
with sDataSet do begin
close;
sql.text := originalSQL + format(sSort,[sStr]);
open;
end;
end;
sList.free;
End
Else
MessageDlg('Cannot sort on this field', mtinformation, [mbOK], 0);
end;
end.
--
Eddie Shipman
