but I couln;d able use this without dataset or datatable, how can I do when I have bindingsource.

Hello,

As far as I understand your data source is some list of T class. So you could do something similar to the approach shown  in the attached sample  

Please let me know if you have any further questions.

I am making simple , how can ignores error in cell, can I show error in only rowselector.

I am attaching you sample, if u try totalattenddays in child table more then 31 gives you error icon in all cell of parent table , how can I set on error only on rowselector on that time.

modified:  if I make RowAndCell then it will through icon on every cell of parent row, when I got error on child row.

Thanks Hristo, But what happen if there is any data validation error on parent table , it shouldn't show icon on parent relative cell , if I make RowAndCell then it will through icon on every cell of parent row, so there is not any way to set error icon on rowselector and relative cell both parent and child level.

Hello ,

You could apply SupportDataErrorInfo by band level, so on your second band you could apply this property to CellOnly for example and also you should implement validate method, which validates all of your fields and for the Attendence class. Please see attached sample.

Please let me know if you have any further questions.  

In this case, I could n't show any error icon on any cell but only on row selector, what I will do, if will have to show icon on relative cell as well as row selector.

thanks

it is really helpful, but in different scenairio, what should I do if I have to show error in row level as well current error cell.

in parent as well as child band.