C# - How to pass null value if the Byte Array is not provided?

Question

I am trying to pass null value to image database field if the ImageByteArray is not provided to Parameters.Add as shown here

cmd.Parameters.Add(new SqlParameter("@Img", SqlDbType.Image)).Value =
    DBNull.Value ? null : ImageByteArray;

but I am getting error that says

Cannot implicitly convert type 'System.DBNull' to 'bool'

first is that correct way to do it >

if yes the how to pass null value if the ImageByteArray is not provided ?

i do not know if am right what i want to do is passing null to the parameter if the Byte Array is not provided so I avoid the Procedure or function expects parameter '@img', which was not supplied.

Answer 1

DBNull.Value ? null : ImageByteArray;

This part is wrong. Because ternary operator needs to be a boolean result to compare. Try the following one;

(object)ImageByteArray ?? DBNull.Value;

If ImageByteArray is null it will assign DBNull.Value to your sql parameter.

Answer 2

Here's what I'm using:

command.Parameters.Add("@Img", SqlDbType.VarBinary, ImageByteArray == null ? -1 : 
ImageByteArray.Length).Value = ImageByteArray ?? (object)DBNull.Value;

Basically, when you send your byte array to your database, you need to specify if it is empty or not. Sending -1 for the length means the received array will be empty.