Bug 1985

Environment:

I am using Spring4d to hold/manipulate data and represent it as dataset using Spring.Data.ObjectDataSet. TObjectDataSet is a descendant of TDataSet and can hold data in an iList. 

On a sample form I have a grid, data is linked from the TObjectDataset. Everything works fine until I put a OnFilterRecord method on my data which filters the data.

If any data passes the filter the grid displays it normally. However, when no records conform to criteria (the dataset is empty) then an exception is raised stating, "Error: Selected Row must be >= -1".

I have traced the error to unit Tee.Grid.Selecton (row 506) - 

Assert(Value>=-1,'Error: Selected Row must be >= -1');


But the cause originates elsewhere:

unit Tee.GridData.DB;

Method procedure TVirtualDBData.Load(const AColumns:TColumns);

  if IDataSet<>nil then
  begin
    TryRelinkFields;

    if KnownCount then    // Returns True
       ChangeSelectedRow(DataSetRecNo-1)  
             //  DataSetRecNo returns -1 --> calls ChangeSelectedRow(-2)
    else
    if Empty then
       ChangeSelectedRow(-1)
    else
       ChangeSelectedRow(0);
  end;

When OnFilterRecord returns no records the call to ChangeSelectedRow wants to set the selected row to -2, causing the exception.