How to check if an ordinals as a key that exist to prevent this error. Unable to cast object of type 'System.DBNull' to type 'System.Byte[]

Question

User-1021989441 posted

I have the following line of code that is giving me an error is I have a DBNull value. How will how go about in resolving this?

byte[] pictureAsByteArray = (byte[])reader.GetValue(ordinals.GetOrdinal("xxxSignature"));

Answer 1

User-719153870 posted

Hi yguyon,

I have the following line of code that is giving me an error is I have a DBNull value. How will how go about in resolving this?

This error is usually caused by a field value is DBNull and it can't be converted to byte[].

To solve this problem, please check DBNull. Value Field and refer to below code:

if (!DBNull.Value.Equals(reader.GetValue(ordinals.GetOrdinal("xxxSignature"))))
            {
                byte[] pictureAsByteArray = (byte[])reader.GetValue(ordinals.GetOrdinal("xxxSignature"));
            }
            else
            {
                byte[] pictureAsByteArray = new byte[0];
            }
        }

Best Regard,

Yang Shen