Not that obvious
Setting a RowFilter that compare’s dates, isn’t quite the same as comparing numbers or strings. For starters Date values must be enclosed within sharp characters # #. The date format is the same as the result of DateTime.ToString() method for invariant or English culture.
Alternatively you can enclose all values within single quotes ‘ ‘. It means you can use string values for numbers or date time values. In this case the current culture is used to convert the string to the specific value. But we don’t always know, or want to know, in advance what the current culture is.