Report designer in mdi child mode

ccy

Hi,

The changes in Fast Report 4 states that the Report Designer able to in non-modal mode, mdi child mode.

However, I found this changes is uesless and serve no purpose. If we create more than one instance of report designer. The Fast report will prompt access violation. Is this a bug or we can't work on more than one designer at the same time in the same process?

AlexTZ

You can run only one instance of FastReport designer. It's by design.

ccy

Will this behavior be enhanced in next version? It doesn't seems a good design in term of OO. I can create more than one instance of designer in Report Builder and it works fine.

Another problem I found out is we can't open 2 preview windows at the same time in Fast Report. Is this the same problem too?

AlexTZ

This is impossible now due to docking behavior.
Regarding preview: one TfrxReport can open one preview window. If you need 2 - use 2 TfrxReport.

ccy

Even if each TfrxReport may open a preview window. But it will cause problem in some unexpected situation due to the DatasetList found in the following procedure in unit frxClass:

function frxFindDataSet(DataSet: TfrxDataSet; const Name: String;
  Owner: TComponent): TfrxDataSet;
var
  i: Integer;
  ds: TfrxDataSet;
begin
  Result := DataSet;
  if Name = '' then
  begin
    Result := nil;
    Exit;
  end;
  if Owner = nil then Exit;
  DatasetList.Lock;
  for i := 0 to DatasetList.Count - 1 do
  begin
    ds := DatasetList[i];
    if AnsiCompareText(ds.UserName, Name) = 0 then
      if not ((Owner is TfrxReport) and (ds.Owner is TfrxReport) and
        (ds.Owner <> Owner)) then
      begin
        Result := DatasetList[i];
        break;
      end;
  end;
  DatasetList.Unlock;
end;

If we have multi instance of TfrxReport but those DataSet store in DataSetList has same UserName, the report output won't get display correctly. I am not sure you able to figure out what's wrong with this singleton design. If you don't, I will provide an example to illustrate this.