Delphi 使用MD5 比对文件

使用MD5的方法比对CXimage里图片是否改变：

Delphi7实现方法：

uses IdHashMessageDigest 

function TForm1.GetImageMD5(cxImage: TcxImage): string;
var
  tmpMD5: TIdHashMessageDigest5;
  ms: TMemoryStream;
begin
  result:='';
  if cxImage.Picture.Graphic=nil then exit;
  tmpMD5:=TIdHashMessageDigest5.Create;
  ms:= TMemoryStream.Create;
  try
    cxImage.Picture.Graphic.SaveToStream(ms);
    result:=tmpMD5.AsHex(tmpMD5.HashValue(ms));
  finally
    tmpMD5.Free;
    ms.Free;
  end;
end;

Delphi2010实现方法：

 uses IdHashMessageDigest

 function GetImageMD5(cxImage: TcxImage): string;
 var
   tmpMD5: TIdHashMessageDigest5;
   ms: TMemoryStream;
 begin
   result:='';
   if cxImage.Picture.Graphic=nil then exit;
   tmpMD5:=TIdHashMessageDigest5.Create;
   ms:= TMemoryStream.Create;
   try
     cxImage.Picture.Graphic.SaveToStream(ms);
     ms.Position:=;
     result:=tmpMD5.HashStreamAsHex(ms);
   finally
     tmpMD5.Free;
      ms.Free;
   end;
 end;

参考：http://www.cnblogs.com/jxsoft/archive/2011/08/08/2131436.html