Ole对象的SQL存取问题!请高手帮忙!!!

Question

我想将OleContainer保存在SQL2000的文件中，然后再读出到另一个OleContainer中，保存时没有问题，但从数据库读出的时候就一直出错!!!代码如下，请高手指点!unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, ADODB, ExtCtrls, Grids, DBGridEh, OleCtnrs, IBBlob;type
  TForm1 = class(TForm)
    con1: TADOConnection;
    dlgOpen1: TOpenDialog;
    qry1: TADOQuery;
    qry1FileID: TAutoIncField;
    qry1FileName: TStringField;
    qry1FileData: TBlobField;
    dbge1: TDBGridEh;
    pnl1: TPanel;
    btn1: TButton;
    ds1: TDataSource;
    btn2: TButton;
    dlgSave1: TSaveDialog;
    OleContainer1: TOleContainer;
    OleContainer2: TOleContainer;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.btn1Click(Sender: TObject);
var
  strFileStream:TMemoryStream;
begin
    strFileStream:=TMemoryStream.Create;
    OleContainer1.SaveToStream(strFileStream);
    with qry1 do
    begin
      Append;
      TBlobField(FieldByName('FileData')).LoadFromStream(strFileStream);
      Post;
    end;
end;procedure TForm1.btn2Click(Sender: TObject);
var
  strFileStream:TMemoryStream;
begin
  with qry1 do
  begin
    strFileStream:=TMemoryStream.Create;
    strFileStream.Clear;
    TBlobField(FieldByName('FileData')).SaveToStream(strFileStream);
    OleContainer2.LoadFromStream(strFileStream);
  end;
end;end.

Answer 1

转一个帖子的上传和读取的代码
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procedure TicwinLogFrm.ReadStreamToDataField(ole: TOleContainer;
DataSource: TDataSource; fieldName: string);
var
stream : TStream;
begin
stream :=
DataSource.DataSet.CreateBlobStream(DataSource.DataSet.fieldbyname(fieldName), bmRead);
try
ole.loadFromStream(stream);
finally
stream.free;
end;
end;procedure TicwinLogFrm.LoadRecordFromDataBase(recNo: integer);
// stream := DataSource.DataSet.CreateBlobStream(DataSource.DataSet.fieldbyname(fieldName),bmRead);
begin
//调用OLE对象为用户编辑用try
//if recNo <> -1 then //初始值为-1
// DBGrid.SelectedIndex := recNo;
caption := '用户：' + ADOQuery.FieldByName('User').AsString +
'上次添加时间：' + FormatDateTime('yyyy-mm-dd hh:nn:ss',
ADOQuery.FieldByName('DATETIME').AsDateTime);
if ADOQuery.FieldByName('Modified').AsBoolean = true then
caption := caption + '--- 被修改过'
else
caption := caption + '--- 还没有被修改过';caption := caption + inttostr(recNo) + '/' +
inttostr(ADOQuery.RecordCount);//(ADOQuery.FieldByName('WorkRec') as TBlobField).SaveToStream(oleDY);
ReadStreamToDataField(OleContainer, DataSource, 'WorkRec'); //这里的DataSource不能是ADOQuery.DataSource
finallyend;
end;procedure TicwinLogFrm.AddStreamToDataField(ole: TOleContainer;
DataSource: TDataSource; fieldName: string);
var
stream : TStream;
begin
stream :=
DataSource.DataSet.CreateBlobStream(DataSource.DataSet.fieldbyname(fieldName), bmwrite);
try
ole.SaveToStream(stream);
finally
stream.free;
end;
end;procedure TicwinLogFrm.AddRecordToDataBase;
// stream := DataSource.DataSet.CreateBlobStream(DataSource.DataSet.fieldbyname(fieldName),bmwrite);
begin
try
with ADOQuery do
begin
append;
end;
ADOQuery.FieldByName('User').AsString := 'o4icwin';
ADOQuery.FieldByName('DATETIME').AsDateTime := now();
//(ADOQuery.FieldByName('WorkRec') as TBlobField).LoadFromStream(OleStream);
AddStreamToDataField(OleContainer, DataSource, 'WorkRec');
ADOQuery.FieldByName('Modified').AsBoolean := false;
ADOQuery.Post;
except
ADOQuery.Cancel;
ADOConnection.RollbackTrans;
end;
end;

Answer 2

OleContainer操作Excel，想把Excel以二进制方式存入数据库，并且以二进制方式读取
存入流：
Procedure SaveToStream(ADOTable1: TAdoTable)
var
  vStream: TMemoryStream;
begin
 try
   try
    vStream := TMemoryStream.Create;
    vStream.Clear;
    OleContainer1.SaveToStream(vStream);
    vStream.Position := 0;
    ADOTable1.Append;
    TBlobField(ADOTable1.FieldByName("BlobField")).LoadFromStream(vStream);
    ADOTable1.Post; 
   finally
      FreeAndNil(vStream);
   end;
  except
    exit;
  end;
end;
读取流：
procedure LoadFromStream(ADOTable1: TAdoTable)
var
  //注意：这里要用TADOBlobStream，如果用TMemoryStream等流类，则会出现错误 
  //OleContainer的二进制流格式和Access的二进制流格式不同
  //TADOBlobStream是专门用来Access的流转化的，TADOBlobStream继承自TMemoryStream
  vStream: TADOBlobStream;
begin
  try   
    vStream := TADOBlobStream.Create(TBlobField(ADOTable1.FieldByName("BlobField")), bmread);
    if (OleContainer1.State = osOpen) or (OleContainer1.State = osUIActive) then
    begin
      OleContainer1.DestroyObject;
    end;
    vStream.Position := 0;
    Olecontainer1.LoadFromStream(vStream);
  except
  end;
end;

Answer 3

var
   str: TADOBlobStream;
  
begin
  ls_sql:='select * from tbDocument where id='+IntToStr(integer(Item.Data));
  ADODoc.Close;
  ADODoc.SQL.Clear;
  ADODoc.SQL.Add(ls_sql);
  ADODoc.Open;
  ADODoc.Edit;
  str:=TADOBlobStream.Create(Tblobfield(ADODoc.FieldByName('content')),bmRead);
  str.Position:=0;
   //锁定画面避免闪烁
  LockwindowUpdate(OleContainer1.Handle);
  LockwindowUpdate(Listview1.Handle);
      OleContainer1.DestroyObject;
      OleContainer1.LoadFromStream(TStream(str));
  .....
   OleContainer1.DoVerb(-1);
  .....
另外还有两个关键:
  数据库一定要使用image类型而不能使用text或其它大二进制类型;
  必须使用TADOBlobStream