How to customize TreeView ItemTemplate based on the node in Xamarin.Forms (SfTreeView)

You can customize the TreeView ItemTemplate based on the node by using DataTemplateSelector in Xamarin.Forms.

You can also refer the following article.

https://www.syncfusion.com/kb/11397/how-to-customize-treeview-itemtemplate-based-on-the-node-in-xamarin-forms-sftreeview

XAML

Binding ItemTemplateSelector to TreeView ItemTemplate.

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:syncfusion="clr-namespace:Syncfusion.XForms.TreeView;assembly=Syncfusion.SfTreeView.XForms"
             xmlns:local="clr-namespace:TreeViewXamarin"
             x:Class="TreeViewXamarin.MainPage">
 
    <ContentPage.BindingContext>
        <local:FileManagerViewModel x:Name="viewModel"/>
    </ContentPage.BindingContext>
 
    <ContentPage.Resources>
        <ResourceDictionary>
            <local:ItemTemplateSelector x:Key="ItemTemplateSelector" />
        </ResourceDictionary>
    </ContentPage.Resources>
    <ContentPage.Content>
        <syncfusion:SfTreeView x:Name="treeView" Indentation="15" AutoExpandMode="AllNodesExpanded" ItemTemplateContextType="Node" 
                               ChildPropertyName="SubFiles" ItemsSource="{Binding ImageNodeInfo}" ItemTemplate="{StaticResource ItemTemplateSelector}"/>
 
    </ContentPage.Content>
</ContentPage>

C#

Apply template to node based on SubFiles.

namespace TreeViewXamarin
{
    public class ItemTemplateSelector : DataTemplateSelector
    {
        public DataTemplate _ParentTemplate { get; set; }
        public DataTemplate _ChildTemplate { get; set; }
        public ItemTemplateSelector()
        {
            this._ParentTemplate = new DataTemplate(typeof(ParentTemplate));
            this._ChildTemplate = new DataTemplate(typeof(ChildTemplate));
        }
        protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
        {
            var node = item as TreeViewNode;
            var treeviewItem = node.Content as FileManager;
            if (treeviewItem == null)
                return null;
            if (treeviewItem.SubFiles!=null)
                return _ParentTemplate;
            else
                return _ChildTemplate;
        }
    }
}

Output