Infralution Support

[Hvid]

Hi.

I'm using your tree view to display fairly large quantities of items (100.000+). I'm using standard data binding (GetParent, GetChildren, GetCellData, GetRowData events).

Given any object in the structure the tree is databinding I would like to be able to select and show that item in the tree view. Essentially I know the id of the item I want to select, so I am able to load this item out of the structure the tree is databinding. However, when I try to databind this particular item the treeview will only display this particular item, and not the parent items that this item is nested below. When debugging I can see that the GetParent event is called on the item, and all the parent items are retrieved, but they are not displayed in the treeview?

Illustration:

---A
---B
---C

1) retrieve C
2) databind C
4) debugging GetParent event handler shows me that B and C are retrieved and set in the event handler.

5) Observed result:
---C (Root item)

6) Expected result
---A
---B
---C (selected)

Any ideas?

[Guest]

Update.

My illustrations had all their spaces removed so I'm redoing those for better understanding:

Illustration:

A
---B
|||---C

5) Observed result:
C (Root item)

6) Expected result
A
---B
|||---C (selected)

[Infralution]

I think you may be confusing setting the datasource with selection - but I'm not entirely sure because I'm not sure what you mean by step 2) below.

[Hvid]

Hi.

I originally wanted to use .SelectedItem and set it to the object I wanted to select. The problem is these objects don't exist until they are databound meaning they are IO loaded dynamically as the tree expands. The structure I am databinding against is stored on the disk with a lightweight id based index on top of it. Whenever I retrieve an item it will be a different object than last time - therefore .SelectedItem doesn't seem to work.

[Infralution]

You can override the Equals() and the GetHashCode() methods for your class so that instances that represent the same underlying object on disk will be treated as the same object.

Virtual Tree uses the IList.IndexOf() and IList.Contains() methods to locate the row for a given domain data item. For nearly all list implementations these rely on the object.Equals() and GetHashCode() methods - so overriding the Equals and GetHashCode methods generally works. If this isn't possible however you could alternatively create a list implementation that implements the IndexOf and Contains methods so that they are based on the underlying object identity.
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Infralution Support