RadzenTree checkboxes with children

Radzen.Blazor Components
1

Hi have a RadzenTree, with the AllowCheckChildren property set to true:

<RadzenTree Data="@tree.Children"
                    AllowCheckBoxes="true"
                    AllowCheckChildren=true
                    @bind-CheckedValues=@SelectedItems
                    class="w-100"
                    Style="height: 500px;"
                    @ref=treePicker>

If I open the page, and select a checkbox, I expect all the children under that to be included in the SelectedItems collection property I am bound to.

However, this only appears to happen if I expand the tree in the UI. If I check a parent node, without ever expanding it's children, then the children do not appear to ever be included in the SelectedItems collection.

Similarly, if I uncheck a parent, all of it's children will continue to be in the SelectedItems collection, unless I expand the node in the UI.

Basically, it seems that AllowCheckChildren only works if the tree is expanded. If someone checks a node without expanding it in the UI, this property does nothing?

Am I missing something to get this to work as expected?

Thanks!

2

When you check a non expanded parent there are no children at that time and that is why they cannot be added to CheckedValues .

3

Thanks enchev,

So Radzen treats all treats virtually, and only creates children at the time of expansion. I guess I can see how that makes sense, particularly for very large trees.

I guess a workaround would be to have clicking a checkbox trigger the expand event for a given node, is there any way to do this?

Or, rather than checking returning a IEnumerable, perhaps a ValueProperty could be assigned that points to a bool on the actual node objects themselves, which would allow the node to take take care of child assignment in a setter property?

4

If you know in your case the children of the checked parent you can add them to CheckedValues manually on parent check.

5

Yes, that works on the Check=true case, but it doesn't work on the Check=false case.

If I uncheck a node, it gets removed from CheckedValues, but all of it's children remain. Unless I'm missing something, there's no easy way to then remove all the orphaned children at this point?

Only way I can think of is maintaining a current and previous state, and diffing them to get the removed nodes?

6

If you add them manually you can remove them manually as well.

7

How though? How would I figure out which ones to manually remove?

I have to store state right? Store the previous IEnumerable, compare it to the current IEnumerabe, to find whatever parent was removed and then manually remove all it's children?

8

Yes, that's the only way in my opinion what you are trying to achieve.

9

Ok, that makes sense.

Thanks enchev, I really appreciate the help!