8.E Shellfolder attributes

Basically, these values look like 0x000000 (0), dword, or 00 00 00 00, binary. 8 digits, 32 possible settings. We prefer to edit binary values, as they can be treated as a simple addition of attributes. Most common shell objects have a binary value, but if it's a dword value, you can rightclick the value and ‘Modify Binary Data’. The numbering is hexadecimal, so each digit can be set from 0 to F (0-15), and can hold up to 4 settings. Possible flags set here can be 1, 2, 4 or 8. If setting is C, that means 1, 4 and 8 are set, only one combination possible all the time. To combine multiple settings and to tweak existing settings, put the values underneath eachother and treat like a regular addition (see example).

In need of a name for the attributes, we'll use their handles as can be used by programmers to retrieve them (by which we found most documentation anyway), the IShellFolder::GetAttributesOf function.

Technically, these values are binary strings, 32 bits long, with 32 possible options inside; every bit can be either 0 (no/false) or 1 (yes/true). The string is then reverted¹, and converted to hexadecimal, and there we have our dword value.

Say, our object has an attribute that says it can be renamed. This is the 5th bit set to 1 (bit 4, we started counting at zero): 00001000000000000000000000000000. Reverted, that's 00000000000000000000000000010000 or 10000. Converted to hexadecimal (use Windows calculator to do conversion), we have 0x10. For conformity, these are always 8 digits long, thus the dword value reads 0x00000010 (16) - 16 being a conversion to decimal.

Now, in some cases there's no dword value, but there's a binary value². The format is not reversed here, so that needs to be undone, but also, these values use ‘bit masks’. A bit mask, here also called ‘byte’, represents 8 bits, and the binary value has four of these (hence 32 bits, on a 32-bit OS that makes a ‘word’), seperately editable. Take the dword value, split up, then reverse order of bytes. Here, 0x00000010 becomes 00 00 00 10, reversed 10 00 00 00.

¹ The reversion is standard, and originates in Intel-based processors using ‘little-endian’ (little end first) architecture (as opposed by, yes, Big-endian). This means the least significant bytes are stored in memory first, then the more significant bytes. A hassle to remember, hence our choice to calculate settings using binary data as the registry shows it.

² Note that this is still REG_DWORD data, but presented as binary data, hexadecimal format. This is not the same binary data as the raw 32 bits set to 0 or 1. If you put 10000000 as hexadecimal in your calculator and convert to binary, you get (000)10000000000000000000000000000, by which you might conclude it's actually bit 3 (4th bit) being set...

Ok, the list of attributes that apply here.They come in categories, and may differ with version of Windows. Not all do work (references: MSDN (1) | MSDN (2) | pinvoke.net):

Note we're trying to describe the attributes from our own perspective - no good for coders, yet lending a hand in molding things in shape for advanced registry fiddlers…

The ‘mask’ attributes at the end of categories are not interesting from our perspective, rather are there as a way for programmers to retrieve information about a set of attributes (what's set for these).

Your desktop recycle bin is a shell object/folder. In its attributes is defined you can't rename or delete it. By adding the SFGAO_CANRENAME flag to the existing attributes you can, though. Default value is 40 01 00 20. This means below attributes are set. This simple addition shows how it should look to be able to rename the bin: