Why does the DataTable get strings do not exceed 255 charact

Question

I have a data file called Access 2003 Table The question "TABCAUHOI" has the following fields:

 

ID int;

NOIDUNG memo;

 

The "NOIDUNG" field has data type as memo, I pour data from excel text file into this table in this access file to check the contents are full as excel file, in C # I query read data into DataTable dt = query 1 message of a content, when debugging Debug.Print (dt.Rows [0] ["NOIDUNG"]. ToString ()); Only get 255 characters in the first string, characters after 255 characters later lost, want to get everything into the DataTable how to do ?