How to stop the file-opening functionality

By Gopinath Taget

Keeping AutoCAD from opening a drawing once the open command has been initiated is difficult. The solution is somewhat unorthodox, but works well.

First, use an AcEditorReactor to handle the beginDwgOpen message. This handler is passed the drawing name as a string, so you can use CFile (CFile is an MFC class so you will need an MFC project for this) to rename it before AutoCAD has a chance to open it. When AutoCAD can’t find find the chosen file, it responds by invoking the open-file dialog box, but we can prevent this by registering our own file-open callback function, which will be called instead. Within this callback function we can rename the drawing file back to its original name, and tell AutoCAD to behave normally the next time an open command is invoked. You can also post any message you like to the user here.

Example:

// ------------------------------------------------------------------    void ADSEdReactor::beginDwgOpen(ACHAR * filename)    {     // Fail Open is a flag to indicate whether to abort the open...     if(failOpen)      {       _tcscpy(modFileName,_T("nlXXXXXX"));// global char       _tmktemp(modFileName);// make a unique name      _tcscpy(originalFileName,filename);// keep the original      try       {        // try to rename the file        CFile::Rename(filename,modFileName);       // to the unique name...       }       catch(...)       {        //error renaming...abort the process        failOpen=false;        return;       }      // This will register fileOpenCB to be called when the       // open command is issued.      acdbHostApplicationServices()->       registerSelectFileCallback(_T("AdskFileOpen"),       fileOpenCB, false, true);     }    }

Acad::ErrorStatus fileOpenCB (short *userCancel, // [out]         TCHAR*& chosenPath, // [out]       void* h, // HWND            const int nFlags,           const TCHAR* prompt,         const TCHAR* dir,          const TCHAR* name,      const TCHAR* type,         int* pnChoice,          bool* pbReadOnly,      const TCHAR* pszWSTags,       void* pReserved)    {     // this is the callback function.      if(failOpen)         {          *userCancel=true;       chosenPath=NULL;         // rename our file back to the        // original name              CFile::Rename(modFileName,originalFileName);        failOpen=false; // reset the flag        }     // This will tell AutoCAD to behave normally when the next open       // command is issued.     acdbHostApplicationServices()->      registerSelectFileCallback(_T("AdskFileOpen"),       fileOpenCB, true, false);     return (Acad::eOk) ;    }