🚀 go-pugleaf

"Dan" <Dan@do.not.spam> wrote in message
news:4683bbbe$1@newsgroups.borland.com...

> What is the best way to do that?

There are three ways to "clear" a TStringGrid:

1) If you want to remove all of the rows, then set the RowCount
property to (FixedRows+1) and then Clear() the remaining row by
itself.  A TStringGrid must always have at least 1 non-fixed row at
all times.  The RowCount cannot be set to 0.  Don't ask me why, I
don't know why Borland designed TStringGrid that way.

2) If you do not want to remove all of the rows, then either:

    a) loop through the Rows[] list calling Clear() on each one

    b) loop through the Cells[][] property (which ou are doing)

> The problem that I am having is that for REALLY LARGE grids,
> clearing the grid takes a long time.  I'd like to see quick
performance
> like I see when I close the app.

Then I suggest not using a TStringGrid at all.  A TListView in virtual
mode (OwnerData = true) would be a lot faster, not to mention have a
cleaner look in general.

> Would it be best to delete the grid and recreate it instead?

Not really.

> This is my code:

It is not necessary to loop through the Cells[][] and Objects[][]
properties as well as set the Row/ColCount properties at the same time
like you are doing.  Simply setting the Row/ColCount is enough to
remove all of the affected cell values just fine.

> //this process is slow, but needed
> //if I don't do this, and just change the col/row counts
> //then the cells may still have values.

That is not true.  All rows/columns that are removed are freed from
memory.  There is nothing physically available for the TStringGrid to
keep displaying for them.

Try this:

    void ClearStringGrid(TStringGrid* sgGrid)
    {
        sgGrid->RowCount = (sgGrid->FixedRows+1);
        sgGrid->Rows[sgGrid->FixedRows]->Clear();
    }


Gambit