ProxyModel to filter a Model from an item that is not the root? or subModel from an Item?

[mbruel]

Hello,
I'm having one main QStandardItemModel and I would like to filter it via a Proxy but not from the root item of my model.
For example, let's say my model is this:

+ Project
   + DataSet
       + Type 1 (2 elems)
           + Elem 1_1
           + Elem 1_1
       + Type 2 (1 elem)
           + Elem 2_1
       + Type 3 (1 elem)
          + Elem 3_1

I would like to be able to filter a certain Types but without displaying the Project and DataSet.
Instead of this:

+ Project
   + DataSet
       + Type 1 (2 elems)
           + Elem 1_1
           + Elem 1_1
       + Type 2 (1 elem)
           + Elem 2_1

I'd like this:

+ Type 1 (2 elems)
    + Elem 1_1
    + Elem 1_1
+ Type 2 (1 elem)
    + Elem 2_1  

Do I have to create a new Model with a subset of main one or could I achieve this with a Proxy?

Can we have a "sub" model of a QStandardItemModel that uses the same QStandardItem but a different root?

[VRonin]

Is the structure of your tree fixed? i.e. will you always filter based by the grand-grand-children of root?

[mbruel]

Yes kind of, basically I've a main View that can modify the model, just adding / deleting grand-grand-grand children but the root, the first child and the types (grand-grand children) are fixed.

When I would use the proxy model to show a sub-model as explained, it is for selection only and the Model itself will be fixed during the whole operation.

[mbruel]

@VRonin
So do you think I could just use a Proxy or do I have to create a copy of the model without the first 2 root items?

[VRonin]

I thought about it but I can't think of an easy solution at the moment. I added it to my to-do list

[mbruel]

@VRonin
I've just found a solution playing with the QTreeView.
Basically, I can just use a proxy to exclude the Items I don't want (Type 3 in my example)
Then it is in the TreeView that I'll hide the two first item by setting the root item:

_ui->treeView->setRootIndex(_treeModel->index(0, 0, _treeModel->index(0, 0)));

In fact it is kind of logic that the View could select what part of a Model it wishes to display

[VRonin]

@mbruel That only works if you only have 1 dataset:

• Project
  • DataSet 1
    • Type 1 (2 elems)
      • Elem 1_1
      • Elem 1_2
    • Type 2 (1 elem)
      • Elem 2_1
  • DataSet 2
    • Type 3 (2 elems)
      • Elem 3_1
      • Elem 3_2
    • Type 4 (1 elem)
      • Elem 4_1

Would not work

[mbruel]

@VRonin
Yep I'd only have one DataSet.
I guess if I had several I would want to keep the DataSets in the Tree and just remove the Project so my view would set the root to the index : _ui->treeView->setRootIndex(_treeModel->index(0, 0));

I could get something like this if I filter let's say Type2 and Type 4 in the proxy

• DataSet 1
  • Type 1 (2 elems)
    • Elem 1_1
    • Elem 1_2
• DataSet 2
  • Type 3 (2 elems)
    • Elem 3_1
    • Elem 3_2