Question

I understand the concept of bytes and declaring variables to save on processing space. I understand that the max value that can be stored in a byte is 255.

I cannot seem to wrap my head around my current issue and was hoping that someone would be able to educate me and help me solve this problem. I don’t have much experience working with byte manipulation.

I was given a project to update and was told that the service that is passing data to my project would start using 2bytes to transfer the ID rather than the 1 byte previously as their parameters have grown.

The current declaration for the variable is:

Dim bytvariable As Byte = 0

What is the new declaration to accept a 2 byte value?

Secondly, how would I be able to convert that 2 byte value into an integer number?

Example, they are passing me this value: 0x138 and it is supposed to come out as 312.

Thank you in advance.

Answer 1

Here’s a summary of the “primitive” datatypes in .NET, and their sizes.

Yes, an Int16 is probably what you want.

Often you’d be reading the binary data from a stream, or getting it from an array of bytes.
To convert from those sources into an Int16, you can do this:

in C#:

byte[] block = new byte[128];
mystream.Read(block, 0, block.Length);
int i = 0;
Int16 value = (Int16)(block[i++] + block[i++] * 256);

In VB.NET, it would be:

Dim block as New Byte(128)
stream.Read(block, 0, block.Length)
Dim i as Int16 = 0
Dim value As Short = CShort((block(i) + (buffer(i+1) * &H100)))
i = i + 2

(I think)