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testing for an empty dataset before deleting a record

Posted on 1998-09-30
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Last Modified: 2006-11-17
How can i test if the dataset is empty before allowing an button click event to delete a record?

If it is empty i want to respond with an appropriate dialog box, but i can't figure out an effective way to check first that it doesn't happen to be empty

any clues?
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Question by:npepper
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dejohn99 earned 200 total points
ID: 1341295
Either of these should work.

Wherever I have used DataSet1.Delete, you should put your normal Delete processing, whatever it may be.

procedure btnDelete1Click (Sender: TComponent)
begin
    if DataSet1.RecordCount = 0 then
        raise Exception.Create ('Dataset '+DataSet1.Name+' is empty');

    DataSet1.Delete;
end;



procedure btnDelete2Click (Sender: TComponent)
begin
    if DataSet1.RecordCount = 0 then
        MessageDlg ('Dataset '+DataSet1.Name+' is empty',
            mtError, [ mbCancel ], 0);
    else
        DataSet1.Delete;
end;


If you are concerned that the RecordCount may not be kept current, you might try this:

procedure btnDelete3Click (Sender: TComponent)
begin
        { EOF and BOF will only both be true for an empty dataset }
        if DataSet1.EOF and DataSet1.BOF then
            MessageDlg ('Dataset '+DataSet1.Name+' is empty',
                mtError, [ mbCancel ], 0)
        else
            DataSet1.Delete;
end;


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