Monday, November 22, 2004

Setting the Appointment Label Text Programmatically

Last week I blogged this Appointment label Colour Changing Event Sink and I mentioned that the appointment label text is located in the property in an undocumented binary form. Well I had a crack at working out what that format is this week and I've come up with the following sample.

Before I start though I must give the following warning, the following piece of code and method is completely unsupported and completely untested. Playing around with binary properties is very unwise unless you really have a good enough grasp to be able to undo any damage you may do trying to set them. The third and last bit is that this will only work if your using the ASCII character set. If you're using other types of character sets (eg a lot of Asian character sets) this wont work.

Because this property is stored in a binary format to work with this in VBS we need something that can read binary and convert it to a hex string which makes it usable. For this I've used Arrayconvert out of this KB article. This library works well and it free and easy to use, the only thing it doesn't do is convert directly a string to hex but you can do this indirectly by first converting the sting to binary and then to hex.

So when no customizations have been made to the labels this property is set to a hex value of 44 Zero's (I know this is not a proper explanation of binary). Or as I'm going to deal with it in the script its 11 groups of "0000". As we have 10 labels then 10 of these groups represent a spacer for each label and the lasts group represents the padding to begin. These groups of 0's are constants in this property they only change in location in relation to the text that's being inserted into the labels.

So the major task that this script does is builds the hex string to be inserted into the property. The first thing it does is sets up a 10 element array to hold all the spacer values for each label. (We already know that this property is going to start with "0000"). The next thing it does is setups up a 10 element array to hold the values for all the customized label texts.

The next part of code then loops through the spacer array and checks to see if any text is going to be inserted from the corresponding label array. If text has been set in that label array element it then first converts the text to a hex string (by way of converting it to binary then back to hex). Then because each character is given 4 digits for storage and USASCII only uses the first 2 digits the hex string is split apart and each hex character representation is padded with "00".

So what we end up with is a hex string representing all the values and spacers that need to be set. Some Exoledb/ADO code is then used to set the x36DC0102 property using the arrayconvert library to convert this hex string into the octent Variant Array of bytes needed for this property.

Thats it as I said you should view this code as experimental and highly suspect. I've posted a downloadable copy of the code here. In my example I'm only setting the two values for blue and green to Internal and External. Eg.

dim objspcarray(9)
dim objlabelarray(9)
set rec = createobject("ADODB.Record")
Set cnvt = CreateObject("ADs.ArrayConvert")
objspcarray(0) = "0000"
objspcarray(1) = "0000"
objspcarray(2) = "0000"
objspcarray(3) = "0000"
objspcarray(4) = "0000"
objspcarray(5) = "0000"
objspcarray(6) = "0000"
objspcarray(7) = "0000"
objspcarray(8) = "0000"
objspcarray(9) = "0000"
objlabelarray(0) = ""
objlabelarray(1) = "External"
objlabelarray(2) = "Internal"
objlabelarray(3) = ""
objlabelarray(4) = ""
objlabelarray(5) = ""
objlabelarray(6) = ""
objlabelarray(7) = ""
objlabelarray(8) = ""
objlabelarray(9) = ""
dstring = "0000"
for i = lbound(objspcarray) to ubound(objspcarray)
if objlabelarray(i) <> "" then
objtooct = cnvt.CvStr2vOctetStr(objlabelarray(i))
objtohex = cnvt.CvOctetStr2vHexStr(objtooct)
for h = 1 to len(objtohex)/2
dstring = dstring & mid(objtohex,((h*2)-1),2) & "00"
end if
dstring = dstring & objspcarray(i)
wscript.echo dstring "file://./backofficestorage/domain/mbx/mailbox/calendar",,3
rec.fields("").Value = cnvt.CvHexStr2vOctetStr(dstring)