Fix: TreeItem Template click does not toggle Checkbox

[ace90210]

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Fix: TreeItem Template click does not toggle Checkbox

Summary

This PR fixes an inconsistency in the RadzenTreeItem component where clicking the content of a custom Template fails to toggle the associated checkbox, whereas clicking default Text works as expected.

The Issue

When AllowCheckBoxes="true", the default rendering logic wraps the item text in a <label for="...">. This leverages native HTML behavior to toggle the checkbox when the text is clicked.

However, when a <Template> is provided, the content is wrapped in a standard <div>. As a result, clicking the template content triggers the Selection (highlight) event via event bubbling, but fails to trigger the Checked state change. This creates a confusing UX where the user expects the checkbox to toggle upon clicking the row, but it does not.

The Fix

I have updated RadzenTreeItem.razor and RadzenTreeItem.razor.cs to programmatically handle the toggle logic when a Template is clicked.

1. Semantics Preserved: Kept the Template container as a <div> (rather than changing it to a <label>) to ensure valid HTML semantics, as custom templates may contain interactive elements (buttons, inputs) which are illegal inside a label.
2. Event Handler: Added a protected OnTemplateClick method that checks if AllowCheckBoxes is true and toggles the CheckedChange state.
3. Binding: Attached @onclick="OnTemplateClick" to the template wrapper div.

Technical Changes

RadzenTreeItem.razor.cs
Added handler logic:

protected async Task OnTemplateClick(MouseEventArgs args)
{
    if (Tree != null && Tree.AllowCheckBoxes && Checkable)
    {
        var currentValue = IsChecked();
        await CheckedChange(currentValue == true ? false : true);
    }
}

RadzenTreeItem.razor
Updated markup to attach the handler:

@if (Template != null)
{
    <div class=@LabelClass @onkeydown:stopPropagation @onclick="@OnTemplateClick">
        @Template(this)
    </div>
} 

Reproduction Steps

1. Create a RadzenTree with AllowCheckBoxes="true".
2. Define a <Template> for RadzenTreeLevel.
3. Run the application and click the text/content inside the tree item (not the checkbox itself).
4. Before Fix: The item is Selected (highlighted blue), but the Checkbox remains unchanged.
5. After Fix: The item is Selected and the Checkbox toggles state.

Checklist

• Changes tested locally.
• Verified that Context Menus still function correctly.
• Verified that Selection (blue highlight) still functions correctly via event bubbling.