Datenübertragung von DB zu LV zu Grid

[DeddyH]

Ich hab da mal eine kleine Demo geschrieben, wie man so etwas machen kann. Die Listview erzeuge ich dynamisch, damit auch die Einstellungen auf jeden Fall passen. Das Dataset ist nur gefaked, wichtig ist der untere Teil im FormCreate.

Delphi-Quellcode:

unit DSFake;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Contnrs, ComCtrls;

type
  TFakeField = class
  private
    FValue: string;
    function GetAsString: string;
  public
    property Value: string read FValue write FValue;
    property AsString: string read GetAsString;
  end;

  TFakeDataset = class
  private
    FIndex: integer;
    FNames,
    FFirstnames,
    FDaysOfBirth: TObjectList;
    function GetEOF: Boolean;
  public
    constructor Create;
    destructor Destroy; override;
    procedure Open;
    procedure Close;
    procedure Next;
    procedure First;
    function FieldByName(const Fieldname: string): TFakeField;
    property EOF: Boolean read GetEOF;
  end;

  TfrmMain = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private-Deklarationen }
    FDataset: TFakeDataset;
    FListview: TListView;
  public
    { Public-Deklarationen }
    property Dataset: TFakeDataset read FDataset;
  end;

var
  frmMain: TfrmMain;

implementation

{$R *.dfm}

{ TFakeDataset }

procedure TFakeDataset.Close;
begin
  //Brauch ma nich
end;

constructor TFakeDataset.Create;
var
  aName, aFirstname, aBirthday: TFakeField;
begin
  (* Wir tun mal so, als wäre das hier eine Ergebnismenge *)
  FNames := TObjectList.Create;
  FFirstNames := TObjectList.Create;
  FDaysOfBirth := TObjectList.Create;
  aName := TFakeField.Create;
  aFirstname := TFakeField.Create;
  aBirthday := TFakeField.Create;
  aName.Value := 'Korn';
  aFirstname.Value := 'Klara';
  aBirthday.Value := '12.12.1912';
  FNames.Add(aName);
  FFirstnames.Add(aFirstname);
  FDaysOfBirth.Add(aBirthday);
  aName := TFakeField.Create;
  aFirstname := TFakeField.Create;
  aBirthday := TFakeField.Create;
  aName.Value := 'Cron';
  aFirstname.Value := 'Maria';
  aBirthday.Value := '01.12.1924';
  FNames.Add(aName);
  FFirstnames.Add(aFirstname);
  FDaysOfBirth.Add(aBirthday);
  aName := TFakeField.Create;
  aFirstname := TFakeField.Create;
  aBirthday := TFakeField.Create;
  aName.Value := 'Beam';
  aFirstname.Value := 'Jim';
  aBirthday.Value := '12.10.1899';
  FNames.Add(aName);
  FFirstnames.Add(aFirstname);
  FDaysOfBirth.Add(aBirthday);
  aName := TFakeField.Create;
  aFirstname := TFakeField.Create;
  aBirthday := TFakeField.Create;
  aName.Value := 'Fiddich';
  aFirstname.Value := 'Glen';
  aBirthday.Value := '02.10.1990';
  FNames.Add(aName);
  FFirstnames.Add(aFirstname);
  FDaysOfBirth.Add(aBirthday);
end;

destructor TFakeDataset.Destroy;
begin
  FNames.Free;
  FFirstNames.Free;
  FDaysOfBirth.Free;
  inherited;
end;

procedure TFakeDataset.First;
begin
  FIndex := 0;
end;

function TFakeDataset.GetEOF: Boolean;
begin
  Result := FIndex >= FNames.Count;
end;

function TFakeDataset.FieldByName(const Fieldname: string): TFakeField;
begin
  if AnsiSameText(Fieldname, 'Name') then
    Result := TFakeField(FNames[FIndex])
  else if AnsiSameText(Fieldname, 'FirstName') then
    Result := TFakeField(FFirstNames[FIndex])
  else if AnsiSameText(Fieldname, 'DayOfBirth') then
    Result := TFakeField(FDaysOfBirth[FIndex])
  else
    Result := nil;
end;

procedure TFakeDataset.Next;
begin
  inc(FIndex);
end;

procedure TFakeDataset.Open;
begin
  First;
end;

{ TFakeField }

function TFakeField.GetAsString: string;
begin
  Result := FValue;
end;

(* Ende Fake, Anfang Simulation *)

procedure TfrmMain.FormCreate(Sender: TObject);
var
  Item: TListItem;
  Column: TListColumn;
begin
  FListview := TListview.Create(self);
  FListview.Parent := self;
  FListview.Align := alClient;
  FListview.ViewStyle := vsReport;
  Column := FListView.Columns.Add;
  Column.Caption := 'Name';
  Column.Width := 120;
  Column := FListView.Columns.Add;
  Column.Caption := 'Vorname';
  Column.Width := 120;
  Column := FListView.Columns.Add;
  Column.Caption := 'Geburtsdatum';
  Column.Width := 120;
  FDataset := TFakeDataset.Create;
  (* So sähe das in etwa auch bei einem "normalen" Dataset aus *)
  Dataset.Open;
  while not Dataset.EOF do
    begin
      Item := FListview.Items.Add;
      Item.Caption := Dataset.FieldByName('Name').AsString;
      Item.SubItems.Add(Dataset.FieldByName('Firstname').AsString);
      Item.SubItems.Add(Dataset.FieldByName('DayOfBirth').AsString);
      Dataset.Next;
    end;
  Dataset.Close;
end;

procedure TfrmMain.FormDestroy(Sender: TObject);
begin
  Dataset.Free;
end;

end.