爲什麼此代碼不起作用?使用TFileStream流對象到文件
我正在寫一個應用程序,可以保存和加載自己的文件,並需要知道如何使用FileStream將對象流式傳輸到文件。
procedure TForm1.btnSaveClick(Sender: TObject);
var
fs: TFileStream;
begin
fs := TFileStream.Create('c:\temp\a.my', fmCreate);
try
fs.WriteBuffer(Image1.Picture.Graphic, SizeOf(TGraphic));
finally
fs.Free;
end;
ShowMessage('ok');
Image1.Picture.Graphic := nil;
end;
procedure TForm1.btnLoadClick(Sender: TObject);
var
fs: TFileStream;
g: TGraphic;
begin
fs := TFileStream.Create('c:\temp\a.my', fmOpenRead);
try
fs.ReadBuffer(g, SizeOf(TGraphic));
Image1.Picture.Graphic := g;
finally
fs.Free;
end;
ShowMessage('ok');
end;
編輯1: 發現做到這一點,但需要更多的幫助方式:
procedure TForm1.btnSaveClick(Sender: TObject);
var
fs: TFileStream;
s: TMemoryStream;
buf: TBytes;
begin
fs := TFileStream.Create('c:\temp\a.my', fmCreate);
s := TMemoryStream.Create;
try
Image1.Picture.Graphic.SaveToStream(s);
SetLength(buf, s.Size);
s.Position := 0;
s.ReadBuffer(buf[0], s.Size);
//fs.WriteBuffer(, SizeOf(Integer)); <-here how do I save an integer which represents the size of the buffer? (so that when reading back i read this first.)
fs.WriteBuffer(buf[0], s.Size);
finally
s.Free;
fs.Free;
end;
ShowMessage('ok');
Image1.Picture.Graphic := nil;
end;
這與我用一個完整的代碼片段回答的其他問題有關:http://stackoverflow.com/questions/7190998/after-assigning-nil-to-timage-picture-graphic-to-clear-the -picture-how-can-i-use/ –