大难题:将文件存放到字段中,如何实现存储进度??

Question

SourStream:TFileStream.Create(FName,fmOpenRead);
TempStream:TMemoryStream.Create; 我只会
TBlobField(FieldByName('DocFile')).LoadFromStream(TempStream); 如何用流的方法实现存储进度显示呢????

Answer 1

有办法了，Mark先，等下写段代码

Answer 2

哈，最后以失败而告终，只解决了一部分，LoadFromStream部分的解决了，后面的没解决
跟踪代码到Recordset.Update(EmptyParam, EmptyParam);ADODB.pas的4473行（Delphi7）发现接下来的调用没法弄了，呵呵
代码如下
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, DB, ADODB, ComCtrls;type
  TForm1 = class(TForm)
    ADOQuery1: TADOQuery;
    Button2: TButton;
    ProgressBar1: TProgressBar;
    ADOConnection1: TADOConnection;
    Button4: TButton;
    ADOQuery1file_name: TWideStringField;
    ADOQuery1file_content: TBlobField;
    procedure Button2Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;type
  TMyBlobField = class(TBlobField)
  public
    procedure LoadFromStream(Stream: TStream; ProgressBar: TProgressBar);
  end;  TMyStream = class(TStream)
  public
    function CopyFrom(Source: TStream; Count: Int64; ProgressBar: TProgressBar): Int64;
  end;var
  Form1: TForm1;
  M1: TMemoryStream;
  F1: TFileStream;implementation{$R *.dfm}procedure TForm1.Button2Click(Sender: TObject);
begin
  M1 := TMemoryStream.Create;
  F1 := TFileStream.Create('G:\F4-第一时间.rm', fmOpenRead);
end;{ TMyBlobField }procedure TMyBlobField.LoadFromStream(Stream: TStream; ProgressBar: TProgressBar);
begin
  with TMyStream(DataSet.CreateBlobStream(Self, bmWrite)) do
  try
    CopyFrom(Stream, Stream.Size, ProgressBar);
  finally
    Free;
  end;
end;{ TMyStream }function TMyStream.CopyFrom(Source: TStream; Count: Int64; ProgressBar: TProgressBar): Int64;
const
  MaxBufSize = $F000;
var
  BufSize, N: Integer;
  Buffer: PChar;
begin
  if Count = 0 then
  begin
    Source.Position := 0;
    Count := Source.Size;
  end;
  Result := Count;
  ProgressBar.Max := Count;
  if Count > MaxBufSize then BufSize := MaxBufSize else BufSize := Count;
  GetMem(Buffer, BufSize);
  try
    while Count <> 0 do
    begin
      if Count > BufSize then N := BufSize else N := Count;
      Source.ReadBuffer(Buffer^, N);
      WriteBuffer(Buffer^, N);
      Dec(Count, N);
      ProgressBar.StepBy(N);
      ProgressBar.Update;
    end;
  finally
    ProgressBar.Position := 0;
    FreeMem(Buffer, BufSize);
  end;
end;procedure TForm1.Button4Click(Sender: TObject);
begin
//select * from Table_2
  with ADOQuery1 do
  begin
    Close;
    Open;
    First;
    Edit;
    FieldByName('file_name').Value := 'G:\孙燕姿Stefanie.rmvb';
    TMyBlobField(FieldByName('file_content')).LoadFromStream(F1, Self.ProgressBar1);
    Post;
    Close;
  end;
end;end.

Answer 3

还是自己解决了.不过要多谢postren(小虫)的帮助,给了我思路.应该使用TSteam.解决办法如下:
var
 SourStream :TFileStream;
 DestStream :TStream;
 Buf: array [1..1024*100] of Char;
.........
.........
         SourStream:=TFileStream.Create(FName,fmOpenRead);
         DestStream:=CreateBlobStream(FieldByName('DocFile'),bmWrite);         SourStream.Position:=0;
         PBForm:= TPBForm.Create( Nil );
         PBForm.show;
         PBForm.FormStyle:=fsStayOnTop;
          try
            while SourStream.Position<SourStream.Size do//如果指针位置不到文件末尾
            begin
              application.ProcessMessages ;
              PBForm.PB1.Position :=Trunc(SourStream.Position/SourStream.Size*100);
              SourStream.Read(Buf,SizeOf(Buf));//读取
              DestStream.Write(Buf,SizeOf(Buf));//写入
            end;
            //TBlobField(FieldByName('DocFile')).LoadFromStream(TempStream);
          finally
            PBForm.Close;
            SourStream.Free;//释放
            DestStream.Free;//释放
          end;
............
............