Access violation error when executing TDataSet's Next method

Question

When looking to move the pointer on to the next record, an error message is shown that says:

Access violation at address 004070E2 in module 'main_p.exe'. Write of address 00000000

Any way of resolving this?

var
  i: integer;
begin
  with dmData.dmEventInfo do
  begin
    tblEventinfo.Open;
    i := 0;
    while NOT tblEventinfo.Eof do
    begin
      arrNames[i] := tblEventinfo['bandname'];
      tblEventinfo.Next;
      i := i + 1;
    end;

  end;
end;

Could you tell what the code is doing, and what types the several classes involved are? And get rid of `with`, it can cause a lot of confusion and it may not do what you want it to do. — Rudy Velthuis, Aug 12 '17 at 18:36
Also what is `tblEventinfo['bandname']`? I think `tblEventinfo` is a table ,No? — Ilyes, Aug 12 '17 at 18:47

score 3 · Accepted Answer · answered Aug 12 '17 at 18:56

You don't show the declaration of the arrNames array , but I think the problem was in the Length.

var
  i: integer;  arrNames : array of string;
begin
    SetLength(arrNames , tblEventinfo.RecordCount);
    i := 0;
    while NOT tblEventinfo.Eof do
    begin
      arrNames[i] := tblEventinfobandname.Value;
      tblEventinfo.Next;
      Inc(I);
    end;

  end;

Access violation error when executing TDataSet's Next method

1 Answers1