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Kelley Wong
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Kelley Wong
asked on 17 Aug 2010, 07:39 AM
I build the treeview code behind ,when i binding the data to the treeview , i find the child treeviewitem is checked while the parent treeviewitem is not .so i debug it and i find the TreeViewItem.ParentTreeView and ParentItem is null ,that is why the issue occurs.
the treeview porperties are set as follows:
could you tell me why TreeViewItem.ParentTreeView and ParentItem is null?
thank you
the treeview porperties are set as follows:
IsTriStateMode="True" IsLineEnabled="True" ItemsOptionListType="CheckList" IsOptionElementsEnabled="True"could you tell me why TreeViewItem.ParentTreeView and ParentItem is null?
thank you
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Hello Kelley Wong,
I created a sample project illustrating what is happening.
Generally item's ParentItem and ParentTreeView are null when the item is not created and showed by the tree view. Meaning that when you try to get the item's ParentItem or ParentTreeView when the item is not visible i.e. his parent is not expanded then these values will be null. This is expected behavior because the tree view is virtualized and only required items at the moment are created. When some item is expanded, it's children are created and initialized. When children are properly initialized then the parent properties are set correctly.
Please take a look at the attached project and experiment with the check button. Try these scenarios:
1. Create Tree --> Check Tree --> look at the VS output --> parent properties are null.
2. Create Tree --> Expand Item 1 --> Check Tree --> look at the VS output --> parent properties are correct.
Sincerely yours,
Hristo Milyakov
the Telerik team
I created a sample project illustrating what is happening.
Generally item's ParentItem and ParentTreeView are null when the item is not created and showed by the tree view. Meaning that when you try to get the item's ParentItem or ParentTreeView when the item is not visible i.e. his parent is not expanded then these values will be null. This is expected behavior because the tree view is virtualized and only required items at the moment are created. When some item is expanded, it's children are created and initialized. When children are properly initialized then the parent properties are set correctly.
Please take a look at the attached project and experiment with the check button. Try these scenarios:
1. Create Tree --> Check Tree --> look at the VS output --> parent properties are null.
2. Create Tree --> Expand Item 1 --> Check Tree --> look at the VS output --> parent properties are correct.
Sincerely yours,
Hristo Milyakov
the Telerik team
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