TList.Add Method

Inserts a new item at the end of the list.

Pascal

function Add(Item: Pointer): Integer;

C++

__fastcall int Add(void * Item);

Description

Call Add to insert a new object at the end of the Items array. Add returns the index of the new item, where the first item in the list has an index of 0.

Add increments Count and, if necessary, allocates memory by increasing the value of Capacity.

Note: Add always inserts the Item pointer at the end of the Items array, even if the Items array contains nil (Delphi) or NULL (C++) pointers.

C++ Examples:

Copy Code

/*
This example creates a list object and inserts two records
into it. The value of the record fields are written on a
paintbox:
*/

#include <memory>       //for STL auto_ptr class

typedef struct AList
{
  int I;
  char C;
} TAList;

typedef TAList* PAList;

void __fastcall TForm1::Button1Click(TObject *Sender)
{
  std::auto_ptr<TList> MyList(new TList);
  // fill the TList
  std::auto_ptr<TAList> AStruct1(new TAList);
  AStruct1->I = 100;
  AStruct1->C = 'Z';
  MyList->Add(AStruct1.get());
  std::auto_ptr<TAList> AStruct2(new TAList);
  AStruct2->I = 200;
  AStruct2->C = 'X';
  MyList->Add(AStruct2.get());
  
  // Go through the list, writing the elements to the
  // canvas of a paintbox component.
  int Y = 10; // position on canvas
  for (int i = 0; i < MyList->Count; i++)
  {
    TAList *AStruct = (PAList) MyList->Items[i];
    PaintBox1->Canvas->TextOut(10, Y, IntToStr(AStruct->I));
    Y += 30;  // Increment Y Value again
    PaintBox1->Canvas->TextOut(10, Y, AStruct->C);
    Y += 30;  //Increment Y Value
  }
}

Delphi Examples:

Copy Code

{
This example creates a list object and inserts two records
into it. The value of the record fields are written on a
paintbox:
} 
procedure TForm1.Button1Click(Sender: TObject);
type
  PMyList = ^AList;
  AList = record
    I: Integer;
    C: Char;
  end;
var
  MyList: TList;
  ARecord: PMyList;
  B: Byte;
  Y: Word;
begin
  MyList := TList.Create;
  try
    New(ARecord);
    ARecord^.I := 100;
    ARecord^.C := 'Z';
    MyList.Add(ARecord); {Add integer 100 and character Z to list}
    New(ARecord);
    ARecord^.I := 200;
    ARecord^.C := 'X';
    MyList.Add(ARecord); {Add integer 200 and character X to list}

    { Now paint the items onto the paintbox}
    Y := 10;             {Variable used in TextOut function}
    for B := 0 to (MyList.Count - 1) do
    begin
      ARecord := MyList.Items[B];
      Canvas.TextOut(10, Y, IntToStr(ARecord^.I)); {Display I}
      Y := Y + 30;  {Increment Y Value again}
      Canvas.TextOut(10, Y, ARecord^.C);  {Display C}
      Y := Y + 30;  {Increment Y Value}
    end;

    { Cleanup: must free the list items as well as the list }
   for B := 0 to (MyList.Count - 1) do
   begin
     ARecord := MyList.Items[B];
     Dispose(ARecord);
   end;
  finally
    MyList.Free;
  end;
end;