As per Expression property of the DataColumn , a filter on DateTime column is created enclosing the date between the number symbol (#)
DateTimeColumn = #dateTimeValue#
In addition the date should be formatted according to the format MM-dd-yyyy as displayed below.
Dim strQuery = String.Format("DateExpired= #{0}#", dtExpired.ToString("MM-dd-yyyy"))
The query above could still fail if the columns also contain times. In such case you should change your formatting to include also output for time "HH:mm:ss" or instead BETWEEN which is more clear.
Another workaround is use SQL CASE to check date and return a flag based ton the value as follows
SELECT
CASE when DateExpired IS NOT NULL AND DateExpired <= Convert(date, getdate()) then 'Y' else 'N' end IsExpired
cheers
Samitha