String was not recognized as a valid Boolean.

please check the dgvFinControl.Rows[i].Cells[0].EditedFormattedValue is not equal to "" and then convert to int

Thanks
Vijay r

Based on the error, value of:
dgvFinControl.Rows[i].Cells[0].EditedFormattedValue
is not a valid boolean value. Assuming you are expecting it to be either true or false (0 or 1), it is something else.

A simple use of DEBUGGER can tell you that. Might be its empty!

If this is the case then the answer suggested by 'E.F.Nijboer' also would not work for you. Your first check before explicit conversion should be for null/empty and then anything else.

Once you have a valid boolean data in the field you can convert it into Boolean and work.

First, we'd have to know what type dgvFinControl.Rows[i].Cells[0] was and what you were storing in it. There would be any number of things that you could do to avoid it.

Without knowing the type, I guess I would write

for (int i = 0; i <= dgvFinControl.Rows .Count - 1; i++)
{
  bool result = false;
  try
  {
    result = Convert.ToBoolean(dgvFinControl.Rows[i].Cells[0].EditedFormattedValue);
  }catch (Exception ex)
  {
    //do something
  }
  if (result)
    iCounter++;
}