DxTreeView.CheckedChanged Event

Fires when a node’s checked state changes.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v25.1.dll

NuGet Package: DevExpress.Blazor

Declaration

[Parameter]
public EventCallback<TreeViewCheckedChangedEventArgs> CheckedChanged { get; set; }

Event Data

The CheckedChanged event's data class is TreeViewCheckedChangedEventArgs. The following properties provide information specific to this event:

Property	Description
CheckedItems	Returns all checked items. Inherited from NavigationCheckedChangedEventArgs<TInfo>.
LastCheckedItems	Returns items checked during the last operation. Inherited from NavigationCheckedChangedEventArgs<TInfo>.
LastUncheckedItems	Returns items unchecked during the last operation. Inherited from NavigationCheckedChangedEventArgs<TInfo>.
Reason	Returns the reason why the TreeView node’s check state changed.

Remarks

Handle the CheckedChanged event to respond to changes. The NavigationCheckedChangedEventArgs<TInfo> class contains the following collections:

CheckedItems

Returns all checked items.

LastCheckedItems

Returns items checked during the last operation.

LastUncheckedItems

Returns items unchecked during the last operation.

The following code snippet handles the CheckedChanged event to respond to user interactions with node checkboxes. The handler obtains the collection of nodes whose state is checked. If the collection is not empty, the code displays the first node’s text.

First checked node: @FirstChecked

<DxTreeView Data="@Data"
            CheckMode="TreeViewCheckMode.Recursive"
            CheckedChanged="CheckedChanged">
    <DataMappings>
        <DxTreeViewDataMapping Text="Name"
                               Key="Id"
                               ParentKey="CategoryId" />
    </DataMappings>
</DxTreeView>

@code {
    string? FirstChecked = "none";
    void CheckedChanged(TreeViewCheckedChangedEventArgs e) {
        var firstCheckedNode = e.CheckedItems.FirstOrDefault();
        FirstChecked = firstCheckedNode != null ? firstCheckedNode.Text : "none";
    }
}

If you want to handle changes on a node’s level, use the DxTreeViewNode.CheckedChanged event.