public bool Invoke(DataRow row, DataRowVersion version) { if (_expr == null) { return(true); } if (row == null) { throw ExprException.InvokeArgument(); } object val = _expr.Eval(row, version); bool result; try { result = ToBoolean(val); } catch (EvaluateException) { throw ExprException.FilterConversion(Expression); } return(result); }