How to Get the length of a TypeCode

Question

I'm sure this is an easy question, but I don't have an answer for. Here's the senario and the question.

I have an array that was stored using in a particular format. The format contains a Header record with muntiple detail records following it. The header of the record tells me what TypeCode was used to store the data, for instance Int32.

I have a routine that takes a byte[] array and converts the byte data back to it's proper format in C#. This routine needs the proper number of bytes to make the conversion successful.

Q. So how can I get the length of bytes from the given TypeCode for passing to the Convert function without having to hardcode the length for every type?

Answer 1

According to How to create Type from TypeCode..., you can't (without a exhaustive switch). Of course the other direction (Type->TypeCode) is trivial.

Answer 2

Given that TypeCode is just an enumeration of a fixed set of values, you could easily hard-code a dictionary of them, e.g.

private static readonly Dictionary<TypeCode,int> TypeCodeLength =
    new Dictionary<TypeCode,int> {
    { TypeCode.Int32, 4 },
    { TypeCode.Int64, 8 },
    { TypeCode.Char, 2 },
    // etc
}

(An equivalent solution would be to use a switch/case statement - they really are equivalent if you're just including values.)

Some, like string and object will be variable though - and others will depend on how you're encoding things like DateTime.

Unless this is using a standard conversion, nothing in the framework is going to be able to give you the lengths. I know hard-coding is generally frowned upon, but in this case it's only in one place and is going to be the simplest option.