Yes this is correct behaviour. If you change the type of a variable (it will have been a string or a number before), then DataTables will get a little upset as you can see :-)
Why would you want to set it to null? If you want to empty the cell, just set it to be a blank string. That way the filtering extra can still parse the data.
Well, null value came from null foreign key filed, which allows nulls, so there are may be nulls, but may be valid key values. It actually not a big problem for us, we can replace nulls with something without sense, for example -1 for null key values, or string.empty for null strings.
Replies
Why would you want to set it to null? If you want to empty the cell, just set it to be a blank string. That way the filtering extra can still parse the data.
Allan
Thanks for support Allan.