How to Use Grid MouseDown Code to Prevent Row/Partition Resize

The information in this article applies to:

• Microsoft Visual FoxPro for Windows, versions 3.0 and 3.0b

SUMMARY

There are no Grid properties that can be used to disable the ability to use the mouse to resize the Grid HeaderHeight and RowHeight or move the Partition Slider. However, code can be placed in the user procedure associated with the Grid MouseDown event to prevent any of the following actions being made with the mouse:

• Resizing the Grid HeaderHeight
• Resizing the Grid RowHeight
• Moving the Partition Slider

MORE INFORMATION

To cause the mouse action to be ignored at certain times, a NODEFAULT is conditionally executed in the Grid MouseDown code depending on the mouse coordinates. This effectively prevents access to the three previously listed properties. The following code example is designed for a grid that can be used in a form, on a page of a pageframe or within a container, regardless of nesting level.

Place the following code in the procedure associated with the MouseDown event for the grid.

****** Start of Grid MouseDown

************************************************************* * If the grid is on a form (not in a container or pageframe), * this section may be omitted. It iterates through * object nesting level for all objects above the grid in the * hierarchy and makes necessary adjustments to nXCoord and * nYCoord. This allows the NODEFAULT to be called at the appropriate * time regardless of whether the grid is in a container, page in * a pageframe, or a combination that contains several layers.

LOCAL cObjlist, nTopTotal, nLeftTotal

cObjlist = '' nLeftTotal = 0 nTopTotal = 0

cObjlist = SYS(1272,this)        && Get object hierarchy for grid
IF TYPE('ThisFormSet') = 'O'     && In a Formset?
  * If so, remove Formset from object list
  cObjlist=SUBSTR(cObjlist,AT('.',cObjlist)+1)

* Strip off grid name and replace form name with 'thisform' cObjlist='thisform' + SUBSTR(cObjlist,AT('.',cObjlist), ;

  RAT('.',cObjlist) - AT('.',cObjlist))

IF !'thisform'==(cObjlist)   && Something more than thisform in hierarchy?
  FOR i=1 TO OCCURS('.',cObjlist) && Number of '.'s = depth of hierarchy
    IF TYPE("EVAL(cObjList+'.left')")='N'   && Does Obj have Left property?
      nLeftTotal = nLeftTotal+EVAL(cObjlist+'.left') + ;
        IIF('3.10' $ OS(1) OR 'NT' $ OS(1),1,0)  && Add it in
    ENDIF
    IF TYPE("EVAL(cObjList+'.top')")='N'    && Does Obj have Top property?
      nTopTotal=nTopTotal+EVAL(cObjlist+'.top')  && Add it in
    ENDIF
    IF EVAL(cObjlist+'.baseclass')='PageFrame' && Is object a PageFrame?
      IF EVAL(cObjlist+'.tabs')=.T. && Does PageFrame have Tabs?
        nTopTotal=nTopTotal+24 + ;
          IIF('3.10' $ OS(1) OR 'NT' $ OS(1),2,0)   && Add in Tab height
      ELSE
        nTopTotal=nTopTotal + ;
          EVAL(cObjlist+'.borderwidth') + ;
          IIF(EVAL(cObjlist+'.SpecialEffect')<2,1,0)
        nLeftTotal=nLeftTotal+EVAL(cObjlist+'.borderwidth')
      ENDIF
      nLeftTotal=nLeftTotal+1+ IIF('3.10' $OS(1) OR 'NT' $ OS(1),1,0)
    ENDIF
    * Pare last object from list
    cObjlist=SUBSTR(cObjlist,1,RAT('.',cObjlist)-1)
  ENDFOR

nXCoord=nXCoord-nLeftTotal   && Compensate nX- and nYCoord for top and left
nYCoord=nYCoord-nTopTotal    && of all containers that hold the Grid

*

WITH this

  * Each of these checks the position of the mouse when the MouseDown
  * is called. If the position is where the click should be ignored,
  * NODEFAULT is issued.

  * This makes rows not resizable

  IF nXCoord < .partition + .Left + 20 AND ;
      nYCoord > .Top + .HeaderHeight + .RowHeight - 5 AND ;
      nYCoord < .Top + .HeaderHeight + .RowHeight + 7
    NODEFAULT
  ENDIF

  * This makes header not resizable

  IF nXCoord < .partition + .Left + 20 AND ;
      nYCoord > .Top + .HeaderHeight - 5 AND ;
      nYCoord < .Top + .HeaderHeight + 7
    NODEFAULT
  ENDIF

  * This makes partition not moveable

  IF MOD(.ScrollBars,2) = 1       && Check for horizontal scrollbar
    IF nXCoord < .partition + .Left + 6 AND ;
    nXCoord >= .partition + .Left AND ;
      nYCoord > .Top + .Height - 19
      NODEFAULT
    ENDIF
  ENDIF

Notes

There are 12 x 20 pixel areas where the pointer changes to a two-headed up/down arrow and the HeaderHeight or RowHeight may be resized. For the HeaderHeight, this is at the lower edge of the Header on the left side of the grid. For the RowHeight, this is at the lower edge of the first row of data on the left side of the grid. Likewise, there is a 19 x 6 pixel area where the pointer changes to a two-headed left/right arrow and the Partition Slider may be moved. This is the small black rectangle to the left of the grid's horizontal scroll bar. Although the pointer will still change when moved over these areas when you use the code example, you will not be able to make adjustments.

There are slight differences between the calculation of the location of objects placed within pageframe and container objects in Windows 95, Windows NT, and Windows 3.1x. The following code conditionally makes these adjustments depending on the operating system:

   IIF('3.10' $ OS(1) OR 'NT' $ OS(1),1,0)