README.md

How to change the TreeView selected node text color in Xamarin.Forms (SfTreeView)

In Xamarin.Forms TreeView, you can change the text color of selected node by using SelectionChanging event.

You can also refer the following aricle.

https://www.syncfusion.com/kb/11362/how-to-change-the-treeview-selected-node-text-color-in-xamarin-forms-sftreeview

C#

TextColor updated in SelectionChanging event, based on selection added or removed.

public class Behavior : Behavior<SfTreeView>
{
    SfTreeView TreeView;
    protected override void OnAttachedTo(SfTreeView treeView)
    {
        TreeView = treeView;
        TreeView.SelectionChanging += TreeView_SelectionChanging;
        base.OnAttachedTo(treeView);
    }
    private void TreeView_SelectionChanging(object sender, Syncfusion.XForms.TreeView.ItemSelectionChangingEventArgs e)
    {
        if (TreeView.SelectionMode == Syncfusion.XForms.TreeView.SelectionMode.Single)
        {
            if (e.AddedItems.Count > 0)
            {
                var item = e.AddedItems[0] as FileManager;
                item.LabelColor = Color.Red;
            }
            if (e.RemovedItems.Count > 0)
            {
                var item = e.RemovedItems[0] as FileManager;
                item.LabelColor = Color.Black;
            }
        }
    }
    protected override void OnDetachingFrom(SfTreeView bindable)
    {
        TreeView.SelectionChanging -= TreeView_SelectionChanging;
        base.OnDetachingFrom(bindable);
    }
}

XAML

LabelColor bound to the Label added to SfTreeView in the ItemTemplate and Behaviour.

<syncfusion:SfTreeView x:Name="treeView" ItemHeight="40" Indentation="15" 
                       ExpanderWidth="40" SelectionMode="Single"
     ChildPropertyName="SubFiles"
     SelectionBackgroundColor="LightGray"
     ItemsSource="{Binding ImageNodeInfo}"
     AutoExpandMode="AllNodesExpanded">
    <syncfusion:SfTreeView.Behaviors>
        <local:Behavior/> 
    </syncfusion:SfTreeView.Behaviors>
    <syncfusion:SfTreeView.ItemTemplate>
        <DataTemplate>
            <ViewCell>
                <ViewCell.View>
                    <Grid x:Name="grid" RowSpacing="0" BackgroundColor="Transparent">
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*" />
                            <RowDefinition Height="1" />
                        </Grid.RowDefinitions>
                        <Grid RowSpacing="0" Grid.Row="0">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="40" />
                                <ColumnDefinition Width="*" />
                            </Grid.ColumnDefinitions>
                            <Grid Padding="5,5,5,5">
                                <Image
                                      Source="{Binding ImageIcon}"
                                      VerticalOptions="Center"
                                      HorizontalOptions="Center"
                                      HeightRequest="35" 
                                      WidthRequest="35"/>
                            </Grid>
                            <Grid Grid.Column="1" RowSpacing="1" Padding="1,0,0,0"
                                  VerticalOptions="Center">
                                <Label x:Name="TextLabel" LineBreakMode="NoWrap" 
                                       Text="{Binding ItemName}" 
                                       TextColor="{Binding LabelColor}"
                                       VerticalTextAlignment="Center">
                                    <Label.FontSize>
                                        <OnPlatform x:TypeArguments="x:Double">
                                            <On Platform="Android,iOS">
                                                <OnIdiom x:TypeArguments="x:Double" Phone="16" Tablet="18" />
                                            </On>
                                        </OnPlatform>
                                    </Label.FontSize>
                                </Label>    
                            </Grid>
                        </Grid>
                        <StackLayout Grid.Row="1" HeightRequest="1"/>
                    </Grid>
                </ViewCell.View>
            </ViewCell>
        </DataTemplate>
    </syncfusion:SfTreeView.ItemTemplate>
</syncfusion:SfTreeView>

Output