Windows® CE 3.0 Application Programming

Using the CEVT_BLOB Property Data Type

The CEVT_BLOB data type allows binary data to be stored in a single property value in a database record up to a maximum length of 64 KB. The CEPROP-VAL structure's val union member for BLOBs is 'blob', and this is a CEBLOB structure:

typedef struct _CEBLOB {
    DWORD           dwCount;
    LPBYTE          lpb;
} CEBLOB;

The dwCount member contains the number of bytes to store in the property, and lpb points to the data to be written. The following code fragments show code that has been added to Listings 4.7 and 4.8 to write and read a timestamp that records the time when the record was written. First, a new property identifier is declared.

const CEPROPID propTimeStamp = MAKELONG(CEVT_BLOB, 103);

The property value specifies the ...