4/11/2024 0 Comments Wpf treeview 1 level example c![]() You can try it out by adding the above code to the sample tree ( CategoryTree.cs), and setting the Filter property in an event handler of the sample app. Node.Visibility = visible ? Visibility.Visible : Visibility.Collapsed / private void ApplyFilter(TreeViewItem node, ShopCategory item)īool visible = filter = null || filter(item) / /// Filters categories if the property /// is set by simply setting the /// property to if the item does /// not match the filter. TreeViewItem node = base.CreateTreeViewItem(item) / /// /// protected override TreeViewItem CreateTreeViewItem(ShopCategory item) This /// is somewhat redundant (as we're also handling ), /// but ensures we also consider root nodes. / /// Immediately applies the filter on newly created items. apply filter foreach (TreeViewItem childNode in treeNode.Items)ĪpplyFilter(childNode, (ShopCategory)childNode.Header) make sure child nodes are being created base.OnNodeExpanded(treeNode) / /// protected override void OnNodeExpanded(TreeViewItem treeNode) / /// Applies the filter on all child nodes. recreate the tree in order to apply the filter on //all currently visible nodes //-> of course, this could be optimized, but it does the job ![]() Set to /// null in order to disable filtering. / /// Defines a filter for items that are bound to the tree. I must say I’m quite satisfied – as the control provides me with virtual methods to intercept everything, the whole thing took about 2 minutes to set up □ Refresh the tree if the filter is being set.Run the filter if a node is being expanded.Apply the filter for new nodes that are being created. ![]() In order to get it working, I needed to do 3 things: The following sample sample operates on the tree implementation of the sample application, and provides a property of type Predicate. In order to provide an alternative, I also looked at filtering the tree on the UI level (filtering = just hide the filtered nodes). On the other hand, it also means that you would have to recreate the tree every time the tree’s filter changes. This approach is dead simple, and it has the advantage that only items that are supposed to be accessible on the tree are being processed by the control. In order to have the tree react to changed filter conditions, calling the tree’s Refresh() method takes care of everything. returns subcategories that should be available through the tree public override ICollectionįoreach(ShopCategory category in parent.SubCategories) Enjoy □ĭownload Sample Project (VS2008): farmtree.zip You find the complete sample under the link below. Of course, you can easily style any of the data templates to your liking. I wrote a simple converter that performs these tasks.
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