Question

I have an enum as below:

[Flags]
public enum AggregationLevel
{
    /// <summary>
    /// 00000001
    /// </summary>
    Department = 1,

    /// <summary>
    /// 00000010
    /// </summary>
    Gbu = 2,

    /// <summary>
    /// 00000100
    /// </summary>
    Division = 4,

    /// <summary>
    /// 00001000
    /// </summary>
    Region = 8,

    /// <summary>
    /// 00010000
    /// </summary>
    Market = 16,

    /// <summary>
    /// 00100000
    /// </summary>
    Cluster = 32,

    /// <summary>
    /// 01000000
    /// </summary>
    Store = 64
}

Then I have a stored procedure parameter which requires a varbinary (array of bytes).

I have an enum instance which should be passed to it:

AggregationLevel thisLevel = AggregationLevel.Department & AggregationLevel.Division;

Then, the value should be passed to this stored procedure:

var parameter = new SqlParameter("@pBitMask", SqlDbType.VarBinary)

parameter = ?

How to convert my ‘thisLevel’ enum to an array of bytes so that it can be assigned to this sql parameter?

Thanks,

Answer 1

A few things..

1) You need to use OR rather than AND:

AggregationLevel thisLevel = AggregrationLevel.Department | AggregationLevel.Division;

2) You can use this sequence so you don’t have to remember powers of 2 in decimal:

0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80, 0x100 ...

3) Finally, varbinary is not what you want. Look at integer or bigint. Enums are stored as ints or longs, and you are limited to the number of bits in an int or a long. If you do want to store in a varbinary, you’ll need to serialise a value to a string of bytes, will will vary depending on whether you want big-endian, how many bytes should be used for storage – maybe it’s even variable, etc. More information needed.

Two options for #3:

A. If it’s just you/code under your control, don’t use varbinary, use int or bigint (depending on number of bits required). Better still (potentially), use bit fields instead, if you’re going to query on them

B. If it’s not, the DBA or app provider will be able to specify how they want their varbinary populated

Hope that helps.