frxdbset.pas

Fastreport最新版本的补丁

{******************************************}
{                                          }
{             FastReport v4.0              }
{               DB dataset                 }
{                                          }
{         Copyright (c) 1998-2007          }
{         by Alexander Tzyganenko,         }
{            Fast Reports Inc.             }
{                                          }
{******************************************}

unit frxDBSet;

interface

{$I frx.inc}

uses
  SysUtils, Windows, Messages, Classes, frxClass, DB
{$IFDEF Delphi6}
, Variants
{$ENDIF};


type
  TfrxDBDataset = class(TfrxCustomDBDataset)
  private
    FBookmark: TBookmark;
    FDataSet: TDataSet;
    FDataSource: TDataSource;
    FDS: TDataSet;
    FEof: Boolean;
    FSaveOpenEvent: TDatasetNotifyEvent;
    FSaveCloseEvent: TDatasetNotifyEvent;
    procedure BeforeClose(Sender: TDataSet);
    procedure AfterOpen(Sender: TDataset);
    procedure SetDataSet(Value: TDataSet);
    procedure SetDataSource(Value: TDataSource);
    function DataSetActive: Boolean;
    function IsDataSetStored: Boolean;
  protected
    function GetDisplayText(Index: String): WideString; override;
    function GetDisplayWidth(Index: String): Integer; override;
    function GetFieldType(Index: String): TfrxFieldType; override;
    function GetValue(Index: String): Variant; override;
    procedure Notification(AComponent: TComponent; Operation: TOperation); override;
  public
    procedure Initialize; override;
    procedure Finalize; override;
    procedure First; override;
    procedure Next; override;
    procedure Prior; override;
    procedure Open; override;
    procedure Close; override;
    function Eof: Boolean; override;

    function GetDataSet: TDataSet;
    function IsBlobField(const fName: String): Boolean; override;
    function RecordCount: Integer; override;
    procedure AssignBlobTo(const fName: String; Obj: TObject); override;
    procedure GetFieldList(List: TStrings); override;
  published
    property DataSet: TDataSet read FDataSet write SetDataSet stored IsDataSetStored;
    property DataSource: TDataSource read FDataSource write SetDataSource stored IsDataSetStored;
  end;


implementation

uses frxUtils, frxRes, frxUnicodeUtils;

type
  EDSError = class(Exception);


{ TfrxDBDataset }

procedure TfrxDBDataset.Notification(AComponent: TComponent; Operation: TOperation);
begin
  inherited;
  if Operation = opRemove then
    if AComponent = FDataSource then
      DataSource := nil
    else if AComponent = FDataSet then
      DataSet := nil
end;

procedure TfrxDBDataset.SetDataSet(Value: TDataSet);
begin
  FDataSet := Value;
  if Value <> nil then
    FDataSource := nil;
  FDS := GetDataSet;
end;

procedure TfrxDBDataset.SetDataSource(Value: TDataSource);
begin
  FDataSource := Value;
  if Value <> nil then
    FDataSet := nil;
  FDS := GetDataSet;
end;

function TfrxDBDataset.DataSetActive: Boolean;
begin
  Result := (FDS <> nil) and FDS.Active;
end;

function TfrxDBDataset.GetDataset: TDataSet;
begin
  if FDataSet <> nil then
    Result := FDataSet
  else if (FDataSource <> nil) and (FDataSource.DataSet <> nil) then
    Result := FDataSource.DataSet
  else
    Result := nil;
end;

function TfrxDBDataset.IsDataSetStored: Boolean;
begin
  Result := Report = nil;
end;

procedure TfrxDBDataset.Initialize;
begin
  FDS := GetDataSet;
  if FDS = nil then
    raise Exception.Create(Format(frxResources.Get('dbNotConn'), [Name]));

  FSaveOpenEvent := FDS.AfterOpen;
  FDS.AfterOpen := AfterOpen;
  FSaveCloseEvent := FDS.BeforeClose;
  FDS.BeforeClose := BeforeClose;
  FEof := False;
  FInitialized := False;
end;

procedure TfrxDBDataset.Finalize;
begin
  if FDS = nil then Exit;
  if FBookMark <> nil then
  begin
    FDS.GotoBookmark(FBookmark);
    FDS.FreeBookmark(FBookmark);
  end;
  FBookMark := nil;

  if CloseDataSource then
    Close;
  FDS.AfterOpen := FSaveOpenEvent;
  FDS.BeforeClose := FSaveCloseEvent;
  FSaveOpenEvent := nil;
  FSaveCloseEvent := nil;
  FInitialized := False;
end;

procedure TfrxDBDataSet.Open;
begin
  if FInitialized then
    Exit;

  FInitialized := True;
  FDS.Open;
  AfterOpen(nil);
  if (RangeBegin = rbCurrent) or (RangeEnd = reCurrent) then
    FBookmark := FDS.GetBookmark else
    FBookmark := nil;

  inherited;
end;

procedure TfrxDBDataSet.Close;
begin
  inherited;
  BeforeClose(nil);
  FDS.Close;
end;

procedure TfrxDBDataset.AfterOpen(Sender: TDataset);
var
  i: Integer;
begin
  GetFieldList(Fields);
  for i := 0 to Fields.Count - 1 do
    Fields.Objects[i] := FDS.FindField(ConvertAlias(Fields[i]));

  if Assigned(FSaveOpenEvent) and (Sender <> nil) then
    FSaveOpenEvent(Sender);
end;

procedure TfrxDBDataset.BeforeClose(Sender: TDataSet);
begin
  if Assigned(FSaveCloseEvent) and (Sender <> nil) then
    FSaveCloseEvent(Sender);

  if FBookMark <> nil then
    FDS.FreeBookmark(FBookmark);
  FBookMark := nil;

  FInitialized := False;
end;

procedure TfrxDBDataSet.First;
begin
  if not FInitialized then
    Open;
  if RangeBegin = rbFirst then
    FDS.First else
    FDS.GotoBookmark(FBookmark);
  FEof := False;
  inherited First;
end;

procedure TfrxDBDataSet.Next;
var
  b: TBookmark;
begin
  if not FInitialized then
    Open;
  FEof := False;
  if RangeEnd = reCurrent then
  begin
    b := FDS.GetBookmark;
    if FDS.CompareBookmarks(b, FBookmark) = 0 then
      FEof := True;
    FDS.FreeBookmark(b);
    Exit;
  end;
  FDS.Next;
  inherited Next;
end;

procedure TfrxDBDataSet.Prior;
begin
  if not FInitialized then
    Open;
  FDS.Prior;
  inherited Prior;
end;

function TfrxDBDataSet.Eof: Boolean;
begin
  if not FInitialized then
    Open;
  Result := inherited Eof or FDS.Eof or FEof;
end;

function TfrxDBDataset.GetDisplayText(Index: String): WideString;
var
  i: Integer;
  s: WideString;
begin
  s := '';
  if not FInitialized then
    Open;
  if DataSetActive then
    if Fields.Count = 0 then
      s := FDS.FieldByName(Index).DisplayText
    else
    begin
      i := Fields.IndexOf(Index);
      if i <> -1 then
      begin
          s := TField(Fields.Objects[i]).DisplayText;
      end
      else
      begin
        s := frxResources.Get('dbFldNotFound') + ' ' + UserName + '."' +
          Index + '"';
        ReportRef.Errors.Add(ReportRef.CurObject + ': ' + s);
      end;
    end
  else
    s := UserName + '."' + Index + '"';
  Result := s;
end;

function TfrxDBDataset.GetValue(Index: String): Variant;
var
  i: Integer;
  v: Variant;
begin
  if not FInitialized then
    Open;
  i := Fields.IndexOf(Index);
  if i <> -1 then
  begin
{$IFDEF Delphi6}
    if TField(Fields.Objects[i]) is TFMTBCDField then
    begin
      if TField(Fields.Objects[i]).IsNull then
        v := Null
      else
        v := TField(Fields.Objects[i]).AsCurrency
    end
    else
{$ENDIF}
    if TField(Fields.Objects[i]) is TLargeIntField then
    begin
      { TLargeIntField.AsVariant converts value to vt_decimal variant type 
        which is not supported by Delphi }
      if TField(Fields.Objects[i]).IsNull then
        v := Null
      else
{$IFDEF Delphi6}
        v := TLargeIntField(Fields.Objects[i]).AsLargeInt
{$ELSE}
        v := TField(Fields.Objects[i]).AsInteger
{$ENDIF}
    end
    else
      v := TField(Fields.Objects[i]).Value
  end
  else
  begin
    v := Null;
    ReportRef.Errors.Add(ReportRef.CurObject + ': ' +
      frxResources.Get('dbFldNotFound') + ' ' + UserName + '."' + Index + '"');
  end;
  Result := v;
end;

function TfrxDBDataset.GetDisplayWidth(Index: String): Integer;
var
  f: TField;
  fDef: TFieldDef;
begin
  Result := 10;
  Index := ConvertAlias(Index);
  f := FDS.FindField(Index);
  if f <> nil then
    Result := f.DisplayWidth
  else
  begin
    try
      if not FDS.FieldDefs.Updated then
        FDS.FieldDefs.Update;
    except
    end;
    fDef := FDS.FieldDefs.Find(Index);
    if fDef <> nil then
      case fDef.DataType of
        ftString, ftWideString: Result := fDef.Size;
        ftLargeInt: Result := 15;
        ftDateTime: Result := 20;
      end;
  end;
end;

function TfrxDBDataset.GetFieldType(Index: String): TfrxFieldType;
var
  f: TField;
begin
  Result := fftNumeric;
  f := FDS.FindField(ConvertAlias(Index));
  if f <> nil then
    case f.DataType of
      ftString, ftWideString, ftMemo:
        Result := fftString;
      ftBoolean:
        Result := fftBoolean;
     end;
end;

procedure TfrxDBDataset.AssignBlobTo(const fName: String; Obj: TObject);
var
  Field: TField;
  BlobStream: TStream;
  sl: TStringList;
begin
  if not FInitialized then
    Open;
  Field := TField(Fields.Objects[Fields.IndexOf(fName)]);
  if (Field <> nil) and Field.IsBlob then
//  if Field is TBlobField then 
  begin
    if Obj is TWideStrings then
    begin
      BlobStream := TMemoryStream.Create;
      sl := TStringList.Create;
      try
        TBlobField(Field).SaveToStream(BlobStream);
        BlobStream.Position := 0;
{$IFDEF Delphi10}
        if Field is TWideMemoField then
          TWideStrings(Obj).LoadFromWStream(BlobStream)
        else
{$ENDIF}
        begin
          sl.LoadFromStream(BlobStream);
          TWideStrings(Obj).Assign(sl);
        end;
      finally
        BlobStream.Free;
        sl.Free;
      end;
    end
    else if Obj is TStream then
    begin
      TBlobField(Field).SaveToStream(TStream(Obj));
      TStream(Obj).Position := 0;
    end;
  end;
end;

procedure TfrxDBDataset.GetFieldList(List: TStrings);
var
  i: Integer;
begin
  List.Clear;
  if FieldAliases.Count = 0 then
  begin
    try
      if FDS <> nil then
        FDS.GetFieldNames(List);
    except
    end;
  end
  else
  begin
    for i := 0 to FieldAliases.Count - 1 do
      if Pos('-', FieldAliases.Names[i]) <> 1 then
        List.Add(FieldAliases.Values[FieldAliases.Names[i]]);
  end;
end;

function TfrxDBDataset.IsBlobField(const fName: String): Boolean;
var
  Field: TField;
  i: Integer;
begin
  if not FInitialized then
    Open;
  Result := False;
  i := Fields.IndexOf(fName);
  if i <> -1 then
  begin
    Field := TField(Fields.Objects[i]);
    Result := (Field <> nil) and Field.IsBlob;
  end;
end;

function TfrxDBDataset.RecordCount: Integer;
begin
  if not FInitialized then
    Open;
  Result := FDS.RecordCount;
end;

end.



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