the handle is invalid

This is a discussion on the handle is invalid within the C++ Programming forums, part of the General Programming Boards category; hmm...yes i belive it is. the "Owner" property is used for garbage disposal in BCB; but that's WAAAY up in ...

  1. #16
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    hmm...yes i belive it is.

    the "Owner" property is used for garbage disposal in BCB; but that's WAAAY up in the inheritance tree, so anything used in that function should be totally initialized at that point.

    anyway, i changed it to memo=new TLabel, and it still occurred.

    i wrapped all the new systemMessage statements with try/catch blocks, where the catch just retries to instatntiate the message, and it's working pretty well. i've gotten a lot of messages displayed with no problems.

    here's the complete code. if someone sees something, please let me know!

    Code:
    //---------------------------------------------------------------------------
    
    #ifndef SystemMessageScreenH
    #define SystemMessageScreenH
    //---------------------------------------------------------------------------
    #include <SysUtils.hpp>
    #include <Classes.hpp>
    #include <Controls.hpp>
    #include <Forms.hpp>
    #include <ComCtrls.hpp>
    //---------------------------------------------------------------------------
    class TSystemMessageScreen;
    class systemMessage : public TPanel
    {
            protected:
                    TLabel *memo;
                    bool READ;
                    TSystemMessageScreen *owner;
                    String __fastcall gettime()
                    {
                            String timeString;
                            TDateTime timeStamp = Now();
                            DateTimeToString(timeString,"yyyy-mm-dd hh:nn:ss.zz",timeStamp);
                            return timeString;
                    }
    
                    __property String timeStamp={read=gettime};
            public:
                    __property bool read={read=READ};
                    __fastcall systemMessage(TSystemMessageScreen *Owner,String msg);
    };
    
    class urgentMessage : public systemMessage
    {
            protected:
                    virtual void __fastcall acknowledgeClick(TObject *Sender);
            public:
                    __fastcall urgentMessage(TSystemMessageScreen *Owner,String msg);
    };
    
    class warningMessage : public urgentMessage
    {
            public:
                    __fastcall warningMessage(TSystemMessageScreen *Owner,String msg);
    };
    
    class alarmMessage : public urgentMessage
    {
            public:
                    __fastcall alarmMessage(TSystemMessageScreen *Owner,String msg);
    };
    
    class PACKAGE TSystemMessageScreen : public TScrollBox
    {
            private:
                    DynamicArray<systemMessage *>messages;
                    unsigned int UNREAD;
            protected:
            public:
                    __fastcall TSystemMessageScreen(TComponent* Owner);
    
                    __property unsigned int unread={read=UNREAD};
    
                    void __fastcall ShowMessage(String msg);
                    void __fastcall ShowWarning(String msg);
                    void __fastcall ShowAlarm(String msg);                                
                    void __fastcall setAcknowledged(systemMessage *msg);
    
            __published:
    };
    //---------------------------------------------------------------------------
    #endif

    Code:
    //---------------------------------------------------------------------------
    
    #include <vcl.h>
    
    #pragma hdrstop
    
    #include "SystemMessageScreen.h"
    #pragma package(smart_init)
    //---------------------------------------------------------------------------
    // ValidCtrCheck is used to assure that the components created do not have
    // any pure virtual functions.
    //
    
    static inline void ValidCtrCheck(TSystemMessageScreen *)
    {
            new TSystemMessageScreen(NULL);
    }
    //---------------------------------------------------------------------------
    __fastcall TSystemMessageScreen::TSystemMessageScreen(TComponent* Owner)
            : TScrollBox(Owner),
            UNREAD(0)
    {
            AutoScroll = true;
    }
    //---------------------------------------------------------------------------
    namespace Systemmessagescreen
    {
            void __fastcall PACKAGE Register()
            {
                     TComponentClass classes[1] = {__classid(TSystemMessageScreen)};
                     RegisterComponents("custom", classes, 0);
            }
    }
    //---------------------------------------------------------------------------
    
    
    void __fastcall TSystemMessageScreen::ShowMessage(String msg)
    {
            try
            {
                    systemMessage *m = new systemMessage(this,msg);
                    m->Align = alTop;
                    messages.Length++;
                    messages[messages.High]=m;
    
            }
            catch(...)
            {
                    ShowMessage(msg);        
            }
    }
    
    void __fastcall TSystemMessageScreen::setAcknowledged(systemMessage *s)
    {
            UNREAD--;
    }
    
    
    void __fastcall TSystemMessageScreen::ShowWarning(String msg)
    {
            try
            {
                    systemMessage *m = new warningMessage(this,msg);
                    m->Align = alTop;
                    messages.Length++;
                    messages[messages.High]=m;
                    UNREAD++;
    
            }
            catch(...)
            {
                    ShowWarning(msg);
            }
    }
    
    void __fastcall TSystemMessageScreen::ShowAlarm(String msg)
    {
            try
            {
                    systemMessage *m = new alarmMessage(this,msg);
                    m->Align = alTop;
                    messages.Length++;
                    messages[messages.High]=m;
                    UNREAD++;
    
            }
            catch(...)
            {
                    ShowAlarm(msg);
            }
    }
    
    __fastcall systemMessage::systemMessage(TSystemMessageScreen *Owner,String msg) :
            TPanel(Owner),
            owner(Owner)
    {
            try
            {
                    memo=new TLabel(this);
                    msg = timeStamp+": "+msg;
    
                    Width = Owner->Width-1;
    
                    Parent = Owner;
                    Align = alTop;
                    Height = 64;
    
                    int numchars = Width/Canvas->TextWidth("0");
    
                    TSysCharSet bchars;
                    bchars << '.' << '-' << ' ';
                    msg = WrapText(msg, "\n", bchars, numchars);
    
                    memo->Transparent = true;
                    memo->Parent = this;
                    memo->Align = alTop;
                    memo->Height = Height-1;
                    memo->Caption = msg;
    
            }
            catch(...){}
    
    }
    
    void __fastcall urgentMessage::acknowledgeClick(TObject *Sender)
    {
            READ = true;
            Color = clWhite;
            owner->setAcknowledged(this);
    }
    
    __fastcall urgentMessage::urgentMessage(TSystemMessageScreen *Owner,String msg) :
             systemMessage(Owner,msg)
    {
            memo->OnClick= acknowledgeClick;
            OnClick= acknowledgeClick;
    }
    
    
    __fastcall warningMessage::warningMessage(TSystemMessageScreen *Owner,String msg) :
             urgentMessage(Owner,msg)
    {
            Color= clYellow;
    }
    
    
    __fastcall alarmMessage::alarmMessage(TSystemMessageScreen *Owner,String msg) :
            urgentMessage(Owner,msg)
    {
            Color= clRed;
    }

  2. #17
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    hmmm....

    i just got "Access is Denied"; the last things in the call stack are:

    7C812A5B: C:\\Windows\system32\kernel32.dll
    400B77A0 C:\\Windows\system32\vcl.bpl

    i have no idea wtf to do with this information.
    Last edited by m37h0d; 07-09-2008 at 08:37 PM.

  3. #18
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    alright, well, i'm positive i've gotten it now.

    it was totally coincidence; it had nothing to do with this message system.

    it was a threading conflict, trying to draw on a bitmap.

    http://www.forumammo.com/cpg/albums/...o-facepalm.jpg

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