本文介绍了你如何提取从TGraphicField位图？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我要疯了。
下面是我在做什么。
- 放入一个TClientDataSet，一个的TImage，并在窗体上一个TButton。
- 将Clientdataset1.Filename到biolife.xml
-
按钮双击并添加下列code：
程序TForm31.Button1Click（发件人：TObject的）;
VAR
BF：TBlobField;
BS：TStream;
BM：TBitmap;
开始
ClientDataset1.Open;
ClientDataset1.First;
BF：= ClientDataSet1.FieldByName（'平面'）作为TBlobField;
BS：= ClientDataSet1.CreateBlobStream（BF，bmRead）;
BS.Position：= 0;
BM：= TBitmap.Create;
尝试
BM.LoadFromStream（BS）;
最后
BM.Free;
结束;
结束;
运行它。当我这样做，我得到位图图像无效。
咦？该数据一直是位年 - ？什么是错
解决方案
"BLOB header" is misleading there, it appears to be a remnant of Paradox storage format for graphic memos.
(* from DB *)
{ Paradox graphic BLOB header }
type
TGraphicHeader = record
Count: Word; { Fixed at 1 }
HType: Word; { Fixed at $0100 }
Size: Longint; { Size not including header }
end;
procedure TForm1.FormClick(Sender: TObject);
const
HeaderSize = SizeOf(TGraphicHeader);
var
Field: TGraphicField;
Stream: TClientBlobStream;
begin
Field := ClientDataSet1.FieldByName('Graphic') as TGraphicField;
Stream := ClientDataSet1.CreateBlobStream(Field, bmRead) as TClientBlobStream;
Stream.SaveToFile('dump.bin'); // examine BLOB and see extra bytes preceding BITMAPFILEHEADER
Assert(Stream.Position = 0);
Stream.Seek(+HeaderSize, soFromCurrent); // discard header, it does not contain anything of use anyways
Image1.Picture.Bitmap.LoadFromStream(Stream);
ClientDataSet1.Next;
end;
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