Hi Francis,
This problem is due to the RowFilter Format declartion in the gridFavoris_QueryCellInfo Event. Use the declaration in the code snippet given below to avoid this.
dtTaches.DefaultView.RowFilter = String.Format("[IDProjet] <= ''{0}''", strIDProjet)
Kindly refer the modified sample.
Let me know if you need futher assistance.
Regards,
Madhan.
TestFavorisClay0_modified.zip