handling null in byte[]

nisar ahmad

Dear All,

I have a windows service which is the bridge between two databases, it fetch records from one database and put it in other, the problem is i have byte[] variable in which i reterived the image from database and push that value in other database it works fine if the value reterived is not null but if the value reterived is null it gives exception, what i want is to handle null value and if it null i will store null. find the below code

SqlCommand com = new SqlCommand("select _CHEQUE_FRONT_IMG from V_NB where Transaction_id=" + _tranid, sqlConn);
byte[] b = (byte[])com.ExecuteScalar();//here is the point where it gives exception when it get null

Please help in this regard

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes15y ago
If that doesn't work, then possibly the value being returned is DBNull rather than null.

Try instead:

object obj = com.ExecuteScalar();

byte[] b = null;

if (!Convert.IsDBNull(obj) && obj != null)
{
b = (byte[])obj
// do your stuff
}
nisar ahmad15y ago
as it executes it gives the same exception
nisar ahmad15y ago
Thanks for your reply but it didnt work
Vulpes15y ago
I'd use the 'as' operator rather than a cast which doesn't throw an exception if the value being converted is null:

byte[] b = com.ExecuteScalar() as byte[];

if (b != null)
{
// do your stuff
}