Using COM+ object pooling with Delphi 6
URL: http://edn.embarcadero.com/article/27568
Abstract: Delphi 6 introduces support for COM+ object pooling, which can provide significant performance improvements under some circumstances. We take a look at Delphi 6s object pooling support. By Vincent Parrett.
Typically, when a client application instantiates a COM+ object, the COM+ runtime will create a new instance of the object. When your client is done with the object, COM+ will destroy the object. This all makes for very efficient use of memory resources, and under normal loads provides quite an acceptable performance.
However, under higher loads the creation and destruction of objects can become a substantial overhead. This is especially true if your COM+ objects are themselves allocating resources, instantiating other objects, and so on.
Object pooling can help in these situations by reducing the number of times an object must be instantiated or destroyed. When pooling is in effect, a client's request for an object will kick of a search to see if there is a ready-to-use object pool for objects of the appropriate type. If so, the COM+ system will provide and activate the object. If not, COM+ will create a new object. When the client is done with the object, COM+ will not destroy the object, but will return it to the object pool so it can be reused.
To get the best out of COM+, your objects should be stateless. To make use of object pooling, they must be stateless objects.
Object pooling with Delphi 6
Supporting object pooling in Delphi 6-generated COM+ objects is simple, however there are a few things that you need to take care with:
Threading model
The first is that you must select the Both threading model, otherwise object pooling will be disabled.
If you get this wrong, don't worry -- it's easy to fix. The New Transactional Object wizard generates code that looks something like this :
initialization
TAutoObjectFactory.Create(ComServer, TMyCOMPlusObject, Class_MyCOMPlusObject,
ci
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Delphi的源码定位方法网上搜索到好像不太多。
这里分享我自己的两个方法。
引用一段话
引用内容
什么是 MAP 文件?
MAP 文件是程序的全局符号、源文件和代码行号信息的唯一的文本表示方法,它可以在任何地方、任何时候使用,不需要有额外的程序进行支持。而且,这是唯一能找出程序崩溃的地方的救星。
DEL ......
procedure TForm1.CheckBox1Click(Sender: TObject);
begin
if CheckBox1.Checked then
SetWindowPos(Handle, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE)
else
SetWindowPos(Handle, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE);
end;//使用Self.FormStyle := fsStayOnTop;会使界 ......
原来是要在FormCreate中加入以下代码:
procedure TTntForm1.TntFormCreate(Sender: TObject);
begin
//这句很关键.对于平台的支持.
if Win32Platform = VER_PLATFORM_WIN32_NT then
Font.Name := 'MS Shell Dlg 2'
else
Font.Name := 'MS Shell Dlg';
......