topic Re: Access to Handle Class in ObjectARX Forum

Access to Handle Class

Anonymous — Thu, 31 Jan 2019 17:00:56 GMT

Hello,

I'm really interested on understanding Handles and how to alter it or access it to learn more about them. Where can I find the Handle Class so I can look at the code. I researched that Handle class is apart of ObjectARX.

Re: Access to Handle Class

autodaug — Fri, 01 Feb 2019 21:44:21 GMT

There's the dbhandle.h header in the arx sdk, which contains the AcDbHandle class definition. As mentioned in the other thread, you can't change an Object's Handle value, since it's a unique identifier for Objects. There are the swapIdWith() and handOverTo() methods, but those are more about one Object taking over another's Handle, rather than simply changing one Object's Handle. And those are fairly complex APIs that are not recommended for general use.

Maybe we can explore the reason for wanting to change Handle or Id values, and find a different way to achieve the higher goal?

Re: Access to Handle Class

Anonymous — Sat, 02 Feb 2019 21:50:07 GMT

The reason for wanting to change the Handle ID is because I want to achieve a task of copy blocks with their attributes and change them in excel and through exporting the excel back to my drawing will update the block attributes. So far I have done the attribute and excel update part but the problem lies with the handle. Let’s say I make a block let’s say for EE terms a circuit breaker with attributes such as device specs. Once I create and define the block, I want to make copies so I can use it as much as I need. The problem I have is that each time I copy this circuit breaker(block) a new handle is made. Let’s say I copy 9 breakers, my excel will show 10 of them(including the orginal). That’s redundant as these blocks will have the same attributes. So instead of changing all of them one by one, I wanted to see if when I make a copy,the copies are will have the same Handle. So Instead of having 10 rows of breakers with different handles I will just have one row with a handle in excel. So when I change the attributes of that single row, it will update the 10 breakers when I import to AutoCAD without doing it one by one on excel.

Re: Access to Handle Class

autodaug — Sun, 03 Feb 2019 01:55:20 GMT

Thank you for the info - I'm not sure I'm getting it, so will have to ask some dumb questions. When you copy the circuit breaker block 9 times, that means you'll have 10 insertions of that block, and yes, each insertion (Block Reference) has to have its own handle (and id) value. Likewise, any Attribute Definitions in the Block will be turned into Attribute Instances for each Block Reference, and those Attribute Instances will each have unique handles.

I assume you're using the AttOut and AttIn commands to get the Attributes into Excel and then back to AutoCAD. But when you say the Blocks all have the same Attributes, do you mean that the Attribute text is the same for each insertion of the block? If so, then it's not really using the power of Attributes, which is to allow different text to be assigned to each block insertion. You might be better off just making the text a simple Text entity in the Block Definition, and then using the Block Editor to modify that text when you want to.

But if you do want to use Attributes and Excel to do this, then I think you do have to have 10 rows in the spreadsheet, for your 10 insertions of the block, and you'll have to update all 10 rows if you want all the Attributes to change. Is that not practical for some reason? I'm not an expert on Excel but I know it's pretty powerful as far as updating multiple rows and columns at once.

I'm no doubt not understanding the workflow properly, so can you provide more details about the commands, APIs and data involved? Are you using a custom ARX app?

Re: Access to Handle Class

Anonymous — Sun, 03 Feb 2019 02:41:05 GMT

No Problem! For this project so far I haven't used any API and a custom app. This is all AutoCAD. For the transferring my data to Excel and back again you are right Im using the AttOut and AttIn commands. The procedure is I create the breaker as a block and define. After that when ever AutoCAD will show me a prompt so I can populate my attributes with data. That is where the data is coming from. With the attribute being the same at each block , this is the end goal Im trying to get. This goal is meant when I copy lets say a block that I defined with attributes such as breakers Identification and current rating, it will copy it(literally copying the block as it is). However when I done so it will copy but it will be under a different handle as you stated. As posted below this is what I get in Excel. I trying to find a way that when I copy a block with a assigned/pupulated attributes that I know i would use on multiple drawings , I can shrink the row size to one row on Excel. In a way that their is a "link between the copies and the original" through having the same handle(of course with Excel showing me this with one row).Its not practical to change one by one as this block can be used in many drawings and you will have a 100s of rows of the same block. So I wanted to see If I can change this by ObjectArx SDK. With the end goal of AutoCAD knowing if a copy of a block has the same attributes as the original, dont make a new handle, some how through programming keep it the same. I was thinking of programming this with the SDK tool kit as I found the code of how AutoCAD Defines and handles "handle ID'S

Re: Access to Handle Class

autodaug — Sun, 03 Feb 2019 20:32:57 GMT

Okay, well, you can do lots of things in an ARX app, but if you don't have an existing app, then there will be some cost in developing and deploying it. Seems like overkill for this use case.

Maybe you can use OLE links instead? Basically, you copy the xls field to the clipboard in Excel, then use PasteSpec in AutoCAD to create an ole link entity, which links to that spreadsheet string. Then put the link entity into your block. This gives you a kind of live link to the text in the xls file, so when the xls file changes, the text in all your block references will automatically (or manually) update. If you haven't look at that, you should check it out..

AutoCAD 2019 OLE Feature