I don't want to change grid recordsource. I want only to add new columns to grid. Currently I use the below. I read your article but haven't found any hind how to change this code.
I found that C5 error occurs ONLY if grid contains combobox. If grid contians only textboxes, c5 error does't occur.

* Form ChangeGridLayout() method.
this.MousePointer = 11
_screen.mousepointer = 11
this.cmdFormSwitch1.setfocus()
this.gridbase1.columncount = 0
this.cmdFormSwitch1.FindNextLayout(thisform.brtabel)
this.gridbase1.Init()
this.gridbase1.setfocus()
this.mousepointer = 0
_screen.mousepointer = 0

>Hi!
>
>Use the grid reconstruction behaviour ;)
>Tr following code and let us know if it works:
>
>

>* close old alias
>select (Grid.RecordSource)
>use
>* here grid lose all its columns
>Grid.ColumnCount = -1
>Grid.RecordSource = "NewAlias"
>Grid.Refresh
>

>
>More about grid reconstruction you can read in the VFP Grids article in the UT magazine, August issue.
>
>HTH.
>
>
>>I have a command F3 "change grid form" in my form.
>>This command destroys all grid columns and then adds new columns to grid.
>>
>>To destroy columns I use
>>
>>

>>  this.gridbase1.columncount = 0  && C5 error occurs in this line
>>

>>
>>I tried also
>>
>>

>>  DO WHILE this.gridbase1.columncount>0
>>    this.gridbase1.DeleteColumn   &&& C5 error occurs in this line
>>    ENDDO
>>

>>
>>Using those commands in VFP 7 will cause C5 error sometimes. This works in VFP 5.
>>
>>Is there a way to re-create grid columns to avoid C5 error ?