Handling long strings returned from COM Objects

ta5

Hi

I have a question which was in parts discussed in http://www.mibuso.com/forum/viewtopic.php?t=7980

There is a COM object which returns a long text (bstr). When using
myStr := myCom.TextData the ffw error occurs:
"The length of the text string exceeds the size of the string buffer."

This is in Navision 4.0, so I thought I could work around with a bigtext variable, but the same problem there.
myBigText.ADDTEXT.. does not work for the same reason and
myBigTxt.READ needs a Stream as input.

BTW, changing the COM object is not an option.

Any comments or workaround on this will be appreciated.
Thanks
Thomas

wonmo

Depending on what you want to do with the long text use the instream and/or the outstream variable types. I had the same error when trying to write to a file and using the outstream variable type solved it.

ta5

Can I use instream when the return value of the com object is bstr?
Do you have a code sample for this?

ta5

Any other ideas?

Btw: In the meantime I developed a kind of a helper dll, which first receives the whole automation object from navision (by a method a) and then returns chunks of the long text back to navision (by a method b). This works quite ok, but is IMHO too complex to use on a regular basis.

Dakkon

I do believe the problem is that Navision still marshals all string data going to and from a COM object as a 250 char text data type. So even if the variable you are assigning to can hold more, Navision still attempts to convert it to a 250 max text variable before doing the actual assignment.

ta5

I sadly came to the same conclusion :shock:
Thank you very much for your feedback.
Thomas

Dakkon

I did something fairly similar as far as a helper object. I created a dynamic string array class object. I use it to package string data back and forth from Navision and my COM objects.

ara3n

I had to write a wrapper in VB that would split the text and send it separately. So that would work.

markvandermeij

Have you tried to handle it as a variant and then converting into a string in Navision?

ta5

Yep, but no success

ara3n

there is no workaround. you have to write a wrapper in VB.