Need lazy load approach for treeview & wanted to maintain only viewing items in mem

[prasad_N]

Thanks, I will look into the link.

Edited : gone through the link, Looks like they have not fixed the bug instead they suggested to build 64-bit application, my application is 64 bit any how .

BTW: how did you do memory management in this case, As you have huge row & we need to build tree before population it onto view.
So did you manage the memory. did you create entire tree (items) and populate it or in some other way ??

[ars]

I have 2 different applications for this. In one application the data are stored in a file, all with equal record size. So if I know a row number, I can compute the location in the file and load the data from there. Of course I do some caching of data to improve performance.

In the second application a single column of data is stored in memory. From the context of the application I know that there is a limitation of 200 million data points (each a double) and I have to keep those data in memory (simple std::vector) anyway because a bunch of numerical algorithms are applied to the data basically reducing the millions of double values into pass/fail results. So I need up to 1.6GB of ram. Allocating this is no big problem in today PCs with 64 bit OS and 8 or 16GB ram. That's for the first column in my table. There are further columns, but the elements of these columns are computed on the fly from the data in the first column when the data in the other column gets read by a view. Therefore I do not need to allocate memory for these columns.

As I mentioned before, I store my data in a std::vector object. The model used by my table view does not store data by itself. Instead, it gets a reference to my data vector and accesses the vector for reading the data. That prevents duplicating data just for displaying them in a table. So in my case, the Qt table model serves as a "glue" between my data (std::vector) and the Qt table view objects.

Best regards
ars

[prasad_N]

Oops.. Thanks for the detailed answer.
In my case this may not work because before populating a tree, need to build the tree this is not a case with table or list view. This is the reason I wanted to go with lazy population model and left with the above doubts.

[prasad_N]

Any suggestions from others ???