In creating a new component that inherits from an existing one as in my case below in which I create a new component by inheriting from a TStringGrid how do I make that when I click on a cell can perform the operation, what is the procedure or function to do this.
For example this code as I do if someone clicks on a cell to create a
ShowMessage ('OK');
In that procedure / function?
unit ExtDBListBox;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, LResources, Forms, Controls, Graphics, Dialogs, Grids, sqldb, db;
type
TExtDBListBox = class(TStringGrid)
private
{ Private declarations }
MyDataSourceList: TDataSource; { il datasource che mi fa vedere i dati nel componente }
MyDataSourceIn: TDataSource; { il datasource che contiene i record sorgenti }
MyDataSourceOut: TDataSource; { il datasource che contiene i record in output, ovvero quelli che vado a modificare }
Intestazione: boolean; { se TRUE vuol dire che devo far vedere l'intestazione dei dati nel componente }
protected
{ Protected declarations }
procedure SetDataSourceList(DataSourceList: TDataSource);
procedure SetDataSourceIn(DataSourceIn: TDataSource);
procedure SetDataSourceOut(DataSourceOut: TDataSource);
procedure SetTitleColumns(TitleColumns: BOOLEAN);
//procedure PrepareCanvas(aCol, aRow: integer; aState: TGridDrawState);
public
{ Public declarations }
constructor Create(TheOwner: TComponent); override;
procedure Requery();
procedure ColumnVisible(ColIndex: integer; Value: boolean);
procedure ColumnAlign(ColIndex: integer; Value: integer);
//procedure PrepareCanvas(aCol, aRow: Integer{; aState: TGridDrawState});
published
{ Published declarations }
property DataSourceList: TDataSource read MyDataSourceList write MyDataSourceList;
property DataSourceIn: TDataSource read MyDataSourceIn write MyDataSourceIn;
property DataSourceOut: TDataSource read MyDataSourceOut write MyDataSourceOut;
property TitleColumns: BOOLEAN read Intestazione write Intestazione;
end;
procedure Register;
implementation
procedure Register;
begin
{$I ExtDBListBox_icon.lrs}
RegisterComponents('Standard',[TExtDBListBox]);
end;
constructor TExtDBListBox.Create(TheOwner: TComponent);
begin
inherited Create(TheOwner);
{cambio il layout della griglia per far si che si veda come se fosse una listbox}
Self.ColCount:=1;
Self.FixedCols:=0;
Self.FixedRows:=0;
Self.AutoEdit:=false;
Self.GridLineWidth:=0;
Intestazione:=FALSE;
{ Self.SetDataSourceList(nil); //mi prendo il datasource dal quale lavorare
Self.SetDataSourceIn(nil); //mi prendo il datasource dal quale lavorare
Self.SetDataSourceOut(nil); //mi prendo il datasource dal quale lavorare
}
end;
procedure TExtDBListBox.Requery();
var
NumRighe, NumColonne: LongInt;
Colonna, Riga: integer;
app:string;
MyTextStyle: TTextStyle;
begin
Self.SetDataSourceList(DataSourceList); //mi prendo il datasource dal quale lavorare
Self.SetDataSourceIn(DataSourceIn); //mi prendo il datasource dal quale lavorare
Self.SetDataSourceOut(DataSourceOut); //mi prendo il datasource dal quale lavorare
Self.Clear; //pulisco la listbox
{ora disegno il dataset}
if ((MyDataSourceList<>nil)AND(not MyDataSourceList.DataSet.EOF)) then
begin
{mi ricavo il numero di colonne che devo stampare a video}
NumColonne:=MyDataSourceList.DataSet.FieldCount;
Self.ColCount:=NumColonne;
{mi scorro velocemente il recordset per capire quante righe ho}
MyDataSourceList.DataSet.First;
NumRighe:=0;
while not MyDataSourceList.DataSet.EOF do
begin
Inc(NumRighe);
MyDataSourceList.DataSet.Next;
end;
{ora che ho il numero di righe mi stampo la griglia}
if Intestazione=TRUE then
begin
Self.RowCount:=NumRighe+1;
{ora inserisco la testata}
for Colonna:=0 to NumColonne-1 do
begin
app:=MyDataSourceList.DataSet.Fields[Colonna].Name;
if Length(Trim(app))<=0 then
app:='Col' + IntToStr(Colonna);
Self.Cells[Colonna,0]:=app;
end;
Riga:=1;
end
else
begin
//Self.Columns.Add.Create(nil);
Self.RowCount:=NumRighe;
Riga:=0;
end;
{ora inserisco i dati}
MyDataSourceList.DataSet.First;
while not MyDataSourceList.DataSet.EOF do
begin
{disegno la singola riga}
for Colonna:=0 to NumColonne-1 do
begin
Self.Cells[Colonna,Riga]:=MyDataSourceList.DataSet.Fields[Colonna].AsString;
end;
Inc(Riga);
MyDataSourceList.DataSet.Next;
end;
end;
Self.AutoSizeColumns; //dimensiona le colonne correttamente
end;
procedure TExtDBListBox.ColumnVisible(ColIndex: integer; Value: boolean);
begin
Self.Columns[ColIndex].Visible:=Value;
end;
procedure TExtDBListBox.ColumnAlign(ColIndex: integer; Value: integer);
begin
if Value<0 then
Self.Columns[ColIndex].Alignment:=taLeftJustify
else if Value=0 then
Self.Columns[ColIndex].Alignment:=taCenter
else
Self.Columns[ColIndex].Alignment:=taRightJustify;
end;
procedure TExtDBListBox.SetDataSourceList(DataSourceList: TDataSource);
begin
Self.MyDataSourceList:=DataSourceList;
end;
procedure TExtDBListBox.SetDataSourceIn(DataSourceIn: TDataSource);
begin
Self.MyDataSourceIn:=DataSourceIn;
end;
procedure TExtDBListBox.SetDataSourceOut(DataSourceOut: TDataSource);
begin
Self.MyDataSourceOut:=DataSourceOut;
end;
procedure TExtDBListBox.SetTitleColumns(TitleColumns: BOOLEAN);
begin
Self.Intestazione:=TitleColumns;
end;
{procedure TExtDBListBox.PrepareCanvas(aCol, aRow: integer; aState: TGridDrawState);
var
a, b: integer;
begin
a:=0;
a:=b;
end;}
end.
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