link.pas

《Kylix程序设计》一书中附带的例程源代码

unit Link;

interface

uses
  Point, Table, Qt, SysUtils, Types, Classes, Variants, QGraphics, QControls,
  QForms, QDialogs, QStdCtrls;

type
  TFrmMain = class(TForm)
    Memo: TMemo;
    BtnAdd: TButton;
    BtnDelete: TButton;
    BtnInsert: TButton;
    BtnSearch: TButton;
    procedure FormCreate(Sender: TObject);
    procedure BtnAddClick(Sender: TObject);
    procedure BtnInsertClick(Sender: TObject);
    procedure BtnDeleteClick(Sender: TObject);
    procedure BtnSearchClick(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    FList: PMyList;
  public
    { Public declarations }
    procedure DoDisplay();
  end;

var
  FrmMain: TFrmMain;


implementation

uses Add, Insert, Delete, Search;

{$R *.xfm}

procedure TFrmMain.FormCreate(Sender: TObject);
begin
  FList := Table.Create();
end;

procedure TFrmMain.BtnAddClick(Sender: TObject);
var
  FrmAdd: TFrmAdd;
  Data: PMyData;
begin
  FrmAdd := TFrmAdd.Create( Self );
  try
    if FrmAdd.ShowModal() = mrOK then
    begin
      // Create a new Data record
      New( Data );
      Data^.X := StrToIntDef( FrmAdd.EdtX.Text, 0 );
      Data^.Y := StrToIntDef( FrmAdd.EdtY.Text, 0 );
      // Add it
      Table.Add( FList, Data );
      DoDisplay();
    end;
  finally
    FrmAdd.Free();
    FrmAdd := nil;
  end;
end;

procedure TFrmMain.BtnInsertClick(Sender: TObject);
var
  FrmInsert: TFrmInsert;
  Data: PMyData;
begin
  FrmInsert := TFrmInsert.Create( Self );
  try
    if FrmInsert.ShowModal() = mrOK then
    begin
      // Create a new Data record
      New( Data );
      Data^.X := StrToIntDef( FrmInsert.EdtX.Text, 0 );
      Data^.Y := StrToIntDef( FrmInsert.EdtY.Text, 0 );
      // Insert it
      Table.Insert( FList, Data, StrToIntDef( FrmInsert.EdtPosition.Text, -1 ) );
      DoDisplay();
    end;
  finally
    FrmInsert.Free();
    FrmInsert := nil;
  end;
end;

procedure TFrmMain.BtnDeleteClick(Sender: TObject);
var
  FrmDelete: TFrmDelete;
begin
  FrmDelete := TFrmDelete.Create( Self );
  try
    if FrmDelete.ShowModal() = mrOK then
    begin
      // Delete it
      Table.Delete( FList, StrToIntDef( FrmDelete.EdtPosition.Text, -1 ) );
      DoDisplay();
    end;
  finally
    FrmDelete.Free();
    FrmDelete := nil;
  end;
end;

procedure TFrmMain.BtnSearchClick(Sender: TObject);
var
  FrmSearch: TFrmSearch;
  Data: PMyData;
  PosReturn: Integer;
  Msg: string;
begin
  FrmSearch := TFrmSearch.Create( Self );
  try
    if FrmSearch.ShowModal() = mrOK then
    begin
      // Create a new Data record
      New( Data );
      Data.X := StrToIntDef( FrmSearch.EdtX.Text, 0 );
      Data.Y := StrToIntDef( FrmSearch.EdtY.Text, 0 );
      // Search it
      PosReturn := Table.Search( FList, Data );
      if PosReturn = -1 then
      begin
        Msg := Format( '[ %d, %d ] not Found.', [ Data.X, Data.Y ] );
        Application.MessageBox( Msg, 'Search Result', [ smbOK ], smsInformation );
        if Memo.HasSelection then Memo.UnSelect();
      end
      else
      begin
//        Msg := Format( '[ %d, %d ] at Node %d.', [ Data.X, Data.Y, PosReturn ] );
//        Application.MessageBox( Msg, 'Search Result', [ smbOK ], smsInformation );
        if Memo.HasSelection then Memo.UnSelect();
        Memo.SetFocus();
        QMultiLineEdit_setCursorPosition( Memo.Handle, 2*PosReturn+2, 0, false ); // false means whether extends old selection.
        Memo.SelLength := Length( Memo.Lines[ 2*PosReturn+2 ] ) + Length( Memo.Lines[ 2*PosReturn+3 ] ) + 2;
      end;
    end;
  finally
    FrmSearch.Free();
    FrmSearch := nil;
  end;
end;

procedure TFrmMain.DoDisplay;
var
  CurrNode: PMyNode;
  NewLine: string;
  i: Integer;
  X, Y: Integer;
begin
  Memo.Lines.Clear();
  case FList^.Count of
    0:
      NewLine := 'No Nodes.';
    1:
      NewLine := 'Total 1 Node.';
    else
      NewLine := Format( 'Total %d Nodes.', [ FList^.Count ] );
  end;
  Memo.Lines.Add( NewLine );
  Memo.Lines.Add( '======================================' );
  // Show the last node of the list
  CurrNode := FList^.Node;
  i := 0;
  while CurrNode <> nil do
  begin
    NewLine := Format( 'Node %d:', [ i ] );
    Memo.Lines.Add( NewLine );
    Point.Access( PMyData( CurrNode^.Data ), X, Y );
    NewLine := Format( '    X = %d;    Y = %d.', [ X, Y ] );
    Memo.Lines.Add( NewLine );
    CurrNode := CurrNode^.Next;
    Inc( i );
  end;
end;

procedure TFrmMain.FormDestroy(Sender: TObject);
begin
  Table.Destroy( FList );
end;

end.