How to change the template of TabItem at runtime

    <Page.DataContext>
        <local:ViewModel/>
    </Page.DataContext>
    <Page.Resources>
        <DataTemplate x:Key="HeaderTemplate">
            <TextBlock Text="{Binding Header}"/>
        </DataTemplate>
        <local:CustomDataTemplateSelector x:Key="TabControlContentTemplateSelector">
            <local:CustomDataTemplateSelector.TextBlockTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Content}" TextWrapping="Wrap" 
                                  Margin="20 0 0 0" FontSize="16"/>
                </DataTemplate>
            </local:CustomDataTemplateSelector.TextBlockTemplate>
            <local:CustomDataTemplateSelector.ButtonTemplate>
                <DataTemplate>
                    <Button Content="{Binding Content}" FontWeight="Bold" 
                            VerticalAlignment="Top" HorizontalAlignment="Left" 
                            Margin="20 0 0 0" FontSize="16"/>
                </DataTemplate>
            </local:CustomDataTemplateSelector.ButtonTemplate>
            <local:CustomDataTemplateSelector.TextBoxTemplate>
                <DataTemplate>
                    <TextBox Text="{Binding Content}" VerticalAlignment="Top" 
                             HorizontalAlignment="Stretch" FontStyle="Italic"
                             Margin="20 0 0 0" FontSize="16"/>
                </DataTemplate>
            </local:CustomDataTemplateSelector.TextBoxTemplate>
        </local:CustomDataTemplateSelector>
    </Page.Resources>
    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <syncfusion:SfTabControl ItemsSource="{Binding TabItems}" Margin="20 20 0 0" 
                                 SelectedIndex="0"
                                 HeaderTemplate="{StaticResource HeaderTemplate}"
                                 ContentTemplateSelector="{StaticResource 
                                 TabControlContentTemplateSelector}"/>
    </Grid>

    public class CustomDataTemplateSelector : DataTemplateSelector
    {
        private DataTemplate textBlockTemplate;
        public DataTemplate TextBlockTemplate
        {
            get { return textBlockTemplate; }
            set { textBlockTemplate = value; }
        }
 
        private DataTemplate buttonTemplate;
        public DataTemplate ButtonTemplate
        {
            get { return buttonTemplate; }
            set { buttonTemplate = value; }
        }
 
        private DataTemplate textboxTemplate;
        public DataTemplate TextBoxTemplate
        {
            get { return textboxTemplate; }
            set { textboxTemplate = value; }
        }
 
        protected override DataTemplate SelectTemplateCore(object item, 
                                           DependencyObject container)
        {
            if(item != null && item is Model)
            {
                if ((item as Model).Header == "TextBlock")
                    return TextBlockTemplate;
                else if ((item as Model).Header == "Button")
                    return ButtonTemplate;
                else if ((item as Model).Header == "TextBox")
                    return TextBoxTemplate;
            }
            return base.SelectTemplateCore(item, container);
        }
    }

    public class Model
    {
        private string header;
 
        public string Header
        {
            get { return header; }
            set { header = value; }
        }
 
        private object content;
 
        public object Content
        {
            get { return content; }
            set { content = value; }
        }
 
    }

    public class ViewModel
    {
        private ObservableCollection<Model> items;
 
        public ObservableCollection<Model> TabItems
        {
            get { return items; }
            set { items = value; }
        }
 
        public ViewModel()
        {
            items = new ObservableCollection<Model>();
            items.Add(new Model() { Header = "TextBlock" , Content = "The SfTabControl provides great flexibility for visual customization and provides many styling and templating properties. Use the ContentTemplateSelector property property to set a data template to affect the appearance of the elements that contain the data items." });
            items.Add(new Model() { Header = "Button", Content = "The SfTabControl provides great flexibility for visual customization and provides many styling and templating properties. Use the ContentTemplateSelector property property to set a data template to affect the appearance of the elements that contain the data items." });
            items.Add(new Model() { Header = "TextBox", Content = "The SfTabControl provides great flexibility for visual customization and provides many styling and templating properties. Use the ContentTemplateSelector property property to set a data template to affect the appearance of the elements that contain the data items." });
        }
    }