Hi, I'm building an application and I use a Datatree to represent a portion of the file system
I'm using the databinding of an Observable collection of FolderElements, Each item contains two collections
Subfolders and Files
The tree works perfectly representing my nodes and files, what I wanted to know is if it is possible
to Hide the Folders and Files nodes when they are empty.
The following is an example:
[root directory]
[subfolders]
[Folder 1]
[subfolders] *
[Files]
[File 10]
[File 11]
[Folder 2]
[Folder n1]
[files]
[file n1]
[files]*
[File on root 1]
[file on root 2]
The Nodes marked wit the * don't have any child node, I was wondering if it is possible to avoid showing them.
The nodes are Part of a Wpf class and are represented by Dependency Properties ObservableCollection<FolderElement> and ObservableCollection<FileElement>
The two classes are dependency objects and their properties are dependency properties.
Is there a way to Hide the Empty objects?
or if this is not possible, Is it possible to Create the Node items from code behind instead of using the databinding allowing us to create them only when needed?
Thank you in advance
Sabrina
Hello Sabrina,
Thank you for your post.
To hide nodes without children, I would recommend handling the InitializeNode event on the XamDataTree. This will fire for each child node when its parent node gets expanded. Using the event arguments of the event handler for the InitializeNode event, you can obtain the node that is initializing from e.Node. From there, you can check the count property of that node's Nodes collection. If it is 0, the node has no children, and you can call e.Node.Control.Visibility = Visibility.Collapsed to hide the node.
You may need to place the e.Node.Control.Visibility setting inside of a Dispatcher.BeginInvoke(new Action(() { visibility code here }))); This is because there is sometimes a small timing issue where the node control is not yet created, and so a null reference exception is thrown on the visibility setting. Placing the visibility code in a dispatcher avoids this.
I hope this helps you. Please let me know if you have any other questions or concerns on this matter.
Sincerely,AndrewAssociate DeveloperInfragistics Inc.www.infragistics.com/support
Thank You for the answer, I will try it and I think it solves my issue.
I have yet a question for you on this.
As you can see from my question, I have two types of child nodes that are Folders and Files.
The Datatree however shows also a node representing the collection
Rootfolder
Subfolders
Folder 1
Files
File 1
File 2
File 3
File 4
I've used the NodeLayout objects to set different Expanded and collapsed images for Files and Folders classes
<ig:NodeLayout Key="FileLayout" TargetTypeName="FileElement" DisplayMemberPath="Name" HeaderText="{x:Static cr:NameListsEditorControlRx.txtFiles}"> <ig:NodeLayout.CollapsedIconTemplate> <DataTemplate> <Image Source="/myapp;Component/Images/btn_032_225.png" Width="16" Height="16"/> </DataTemplate> </ig:NodeLayout.CollapsedIconTemplate> <ig:NodeLayout.ExpandedIconTemplate> <DataTemplate> <Image Source="/Myapp;Component/Images/btn_032_152.png" Width="16" Height="16"/> </DataTemplate> </ig:NodeLayout.ExpandedIconTemplate> </ig:NodeLayout>
The above is an example
However the Subfolders node and the Files Nodes even if being a different class (observable collection of folder or file element) they retainthe same image as their children and this is somehow confusing for the Files list because I've used a Document icon that isnot showing very well the concept of This is a container node to be expanded.
Is there a Way to Change the Expanded Collapsed images of the collections? Even using codebehind it would be not a problem.
Thank You in advance
Hi, After a series of tries I'm sorry to say it does not work (previous answer and question was written before i tried sorry)
The problem is that I don't know why or how, The XamDatagrid creates a "Phantom" node for each collection contained in the node, putting then the collection elements inside that phantom node.
This phantom node does not raise the InitializeNode Event and also, when I inspect the Data content of the nodes from the parent node InitializeNode, the two phantom nodes are present but they contain a casual kind of data type...
The Node containing Subfolders lists itself as a FolderElement (its elements are indeed of that type but it is not a single element, it is a collection).
The Node containing Files lists itself as a FolderElement too (but it is a collection of FileElement)
So I find very difficult to manage things as I need, and watching your samples, unfortunately there is nothing helpful so my question is again
Is there a sample of how to manually build the tree nodes inside a xamDataTree so that I can build it as needed?
thank you in advance