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_EdPosInView( ) API Library Routine

  • Articolo
int _EdPosInView(WHANDLE wh, EDPOS thePos)
WHANDLE wh;            /* Handle of editing window. */
EDPOS thePos;               /* Offset position. */

Remarks

_EdPosInView( ) returns True (an integer other than 0) if the offset position in the file in the specified editing window is visible, or False (0) if not.

For more information on how to create an API library and integrate it with Visual FoxPro, see Accessing the Visual FoxPro API.

Example

The following example opens for editing a file specified by a parameter. After scrolling to the top of the file, the example calls _EdPosInView( ) to check whether the top of file and bottom of file are in view and the results are printed to the screen. Then the example scrolls to the bottom of the file, and again calls _EdPosInView( ) to check whether the top of file and bottom of file are in view.

Visual FoxPro Code

SET LIBRARY TO EDPOSINV
= POSINVIEW("x")

C Code

#include <pro_ext.h>

void putLong(long n)
{
   Value val;

   val.ev_type = 'I';
   val.ev_long = n;
   val.ev_width = 10;

   _PutValue(&val);
}

FAR Example(ParamBlk FAR *parm)
{
#define pFILENAME ((char FAR *) _HandToPtr(parm->p[0].val.ev_handle))

   WHANDLE wh;
   EDENV EdEnv;

   if (!_SetHandSize(parm->p[0].val.ev_handle,
      parm->p[0].val.ev_length+1))
   {
      _Error(182); // "Insufficient memory"
   }
   pFILENAME[parm->p[0].val.ev_length] = '\0';

   _HLock(parm->p[0].val.ev_handle);
   wh = _EdOpenFile(pFILENAME, FO_READONLY);
   _HUnLock(parm->p[0].val.ev_handle);

   _EdGetEnv(wh, &EdEnv);

   _EdScrollToPos(wh, 0, FALSE);
   _PutStr("\n_EdScrollToPos(wh, 0)");
   _PutStr("\n_EdPosInView(wh, 0) =");
   putLong(_EdPosInView(wh, 0));
   _PutStr("\n_EdPosInView(wh, EdEnv.length) =");
   putLong(_EdPosInView(wh, EdEnv.length));

   _EdScrollToPos(wh, EdEnv.length, FALSE);
   _PutStr("\n_EdScrollToPos(wh, EdEnv.length)");
   _PutStr("\n_EdPosInView(wh, 0) =");
   putLong(_EdPosInView(wh, 0));
   _PutStr("\n_EdPosInView(wh, EdEnv.length) =");
   putLong(_EdPosInView(wh, EdEnv.length));
}

FoxInfo myFoxInfo[] = {
   {"POSINVIEW", (FPFI) Example, 1, "C"},
};
FoxTable _FoxTable = {
   (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};

See Also

_EdGetPos( ) API Library Routine | _EdGetPos( ) API Library Routine | _EdSetPos( ) API Library Routine | Accessing the Visual FoxPro API