Firemonkey: TGrid usage on Embarcadero C++ Builder XE3

Question

I\'m try to build a tool that reads data from a database and displays it as a table using a TGrid in Firemonkey. I need to use different types of columns like TCheckColumn and T

Answer 1

I can't give C++ code but a Delphi example should be easy enough to translate.

You get and set all cell values the same way, by listening for the OnGetData and OnSetData events, get take/give values of type TValue (XE3 and later). It's just a case of returning the appropriate type in the TValue:

uses System.RTTI;

procedure Form1.Grid1GetValue(Sender: TObject;const Col, Row: Integer;var Value: TValue);
begin
  if Col = 1 then
    Value := TValue.From<Integer>(1)
  else if Col = 2 then
    Value := TValue.From<String>('Hello')
  else if Col = 3 then
    Value := Tvalue.From<Single>(1.0);
end;

procedure Form1.Grid1SetValue(Sender: TObject;const Col, Row: Integer;const Value: TValue);
begin
  if Col = 1 then
    I := Value.As<Integer>
  else if Col = 2 then
    St := Value.As<String>
  else if Col = 3 then
    Si := Value.As<Single>;
end;

As far as I can tell a popup menu can't accept or give data.

Answer 2

TGris does not store any data, you should create your own datastorage.

Example: TGrid with TCheckColumn, TStringColumn and TPopupColumn

type
  TField = record
    Checked:  Boolean;
    Name:     string;
    Column:   Byte;
  end;

var
  Fields: TList<TField>;

function SetField(const AChecked: Boolean; const AName: string; const AColumn: Byte): TField;
begin
  with Result do begin
    Checked := AChecked;
    Name    := AName;
    Column  := AColumn;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  I: Integer;
begin
  Fields := TList<TField>.Create;
  Fields.Add(SetField(True, 'Name', 1));
  Fields.Add(SetField(True, 'Login', 2));
  Fields.Add(SetField(True, 'Password', 3));
  for I := 1 to Fields.Count do
    PopupColumn1.Items.Add('Column ' + IntToStr(I));
  gdFields.RowCount := Fields.Count;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  Fields.Free;
end;

procedure TFormExport.gdFieldsGetValue(Sender: TObject; const Col, Row: Integer; var Value: TValue);
begin
  case gdFields.Columns[Col].TabOrder of
    0:  Value := Fields[Row].Checked;
    1:  Value := Fields[Row].Name;
    2:  Value := Fields[Row].Column - 1;
  end;
end;

procedure TFormExport.gdFieldsSetValue(Sender: TObject; const Col, Row: Integer; const Value: TValue);
var
  FRec: TField;
begin
  FRec := Fields[Row];
  case gdFields.Columns[Col].TabOrder of
    0:  FRec.Checked := Value.AsBoolean;
    1:  FRec.Name    := Value.AsString;
    2:  FRec.Column  := Value.AsInteger + 1;
  end;
  Fields[Row] := FRec;
end;

Now all data from your datastorage will be changed after editing your TGrid, but possible bug in TGrid - never received OnSetValue after changing PopupColumn

Answer 3

In order to solve your problem, redefine the TCheckCell class in the following way:

#include <FMX.Grid.hpp>
#include <boost/dynamic_bitset.hpp>

class CheckCellClass:public TCheckCell
{
public:
 __fastcall virtual CheckCellClass(System::Classes::TComponent*AOwner):TCheckCell(AOwner)
 {
 };

 virtual System::Rtti::TValue __fastcall GetData(void)
 {
  return TValue::From<bool>(this->IsChecked);
 };

 virtual void __fastcall SetData(const TValue&Value)
 {
  TValue V(Value);
  this->IsChecked=V.AsBoolean();
 };
};

//Redifine TCheckColumn class
class CheckColumnClass:public TCheckColumn
{
private:
 virtual Fmx::Controls::TStyledControl*__fastcall CreateCellControl(void)
 {
  CheckCellClass*Cell=new CheckCellClass(this);
  Cell->OnChange     =&(this->DoCheckChanged);
  return Cell;
 };

public:
__fastcall CheckColumnClass(System::Classes::TComponent*AOwner):TCheckColumn(AOwner)
 {
 };
};

//global Data for Save curent State Cell

boost::dynamic_bitset<unsigned char>FullDiscreteInputs;

Add To Grid In Constuctor
 FullDiscreteInputs.resize(100);
 DiscreteInputsGrid->RowCount=FullDiscreteInputs.size();    
 CheckColumnClass* DiscreteInPutsCheckColumn        =new CheckColumnClass(DiscreteInputsGrid);
 DiscreteInputsGrid->AddObject(CoilsCheckColumn);

void __fastcall TForm1::DiscreteInputsGridGetValue(TObject*Sender, const int Col, const int Row,TValue&Value)
{
 //...

 if(DiscreteInputsGrid->ColumnByIndex(Col)==DiscreteInPutsCheckColumn)
 {
 Value=TValue::From<bool>(FullDiscreteInputs[Row]);
 }
 //...
}

//---------------------------------------------------------------------------
void __fastcall TForm1::DiscreteInputsGridSetValue(TObject*Sender, const int Col, const int Row, const TValue&Value)
{
 TValue V(Value);
 if(DiscreteInputsGrid->ColumnByIndex(Col)==DiscreteInPutsCheckColumn)
 {
 FullDiscreteInputs[Row]=V.AsBoolean();
 }
}
//---------------------------------------------------------------------------