在构造函数中的神秘堆栈溢出

Question

这是我的程序使用的类层次结构:

TForm_Upgrade_Database的构造函数如下所示:

__fastcall TForm_Upgrade_Database :: TForm_Upgrade_Database(TComponent*Owner,int newest_version):TForm(Owner){}

在尝试创建公式的实例之后

TForm_Upgrade_Database *dlg = new TForm_Upgrade_Database(this, newest_version);

我的程序抛出EStackOverflow异常

我停止了程序并在TForm_Upgrade_Database构造函数中使用断点再次运行它.几步之后callstack看起来像这样:

如何TCustomForm构造函数继续尝试调用其后代的构造函数???

最小的测试用例:

so_project.cpp:

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "f_form.h"
//---------------------------------------------------------------------------
WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
   TForm_Upgrade_Database *form = new TForm_Upgrade_Database(NULL, 10);
   delete form;
   form = NULL; 

   return 0;
}
//---------------------------------------------------------------------------

f_form.cpp:

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "f_form.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm_Upgrade_Database *Form1;
//---------------------------------------------------------------------------
__fastcall TForm_Upgrade_Database::TForm_Upgrade_Database(TComponent* Owner, int x)
   : TForm(Owner)
{
}
//---------------------------------------------------------------------------

f_form.h:

//---------------------------------------------------------------------------

#ifndef f_formH
#define f_formH
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
//---------------------------------------------------------------------------
class TForm_Upgrade_Database : public TForm
{
__published:    // IDE-managed Components
private:    // User declarations
public:     // User declarations
   __fastcall TForm_Upgrade_Database(TComponent* Owner, int x);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm_Upgrade_Database *Form1;
//---------------------------------------------------------------------------
#endif

Answer 1

TForm有一个虚拟构造函数，它按顺序接受TComponent*和参数。int您正在重写该构造函数。通过调用仅接受参数的基类构造函数TComponent*，当这些构造函数在内部相互调用时，您实际上创建了一个递归循环。

解决办法就是求真者所说的。您必须更改派生构造函数的参数，以便不再覆盖基类TComponent*/int构造函数。更改参数的顺序就足够了，或者您可以将其更改int为不同的数据类型。