How to create context menu in SfDataGrid?

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
                        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                        xmlns:local="clr-namespace:ContextMenuSupport"
                        x:Class="ContextMenuSupport.MainPage"
                        xmlns:sfgrid="clr-namespace:Syncfusion.SfDataGrid.XForms;assembly=Syncfusion.SfDataGrid.XForms">
<ContentPage.BindingContext>
    <local:ViewModel />
</ContentPage.BindingContext>
<ContentPage.Content>
    <RelativeLayout x:Name="relativeLayout">
      <sfgrid:SfDataGrid x:Name="dataGrid"
                         ItemsSource="{Binding Collection}"
                         ColumnSizer="Star"
                         RelativeLayout.WidthConstraint="{ConstraintExpression
                                                      Type=RelativeToParent,Property=Width,Factor=1,Constant=0}"
                         RelativeLayout.HeightConstraint="{ConstraintExpression
                                                      Type=RelativeToParent,Property=Height,Factor=1,Constant=0}"
                         GridLongPressed="DataGrid_GridLongPressed"
           />     
   </RelativeLayout>
 </ContentPage.Content>
</ContentPage>

public partial class MainPage : ContentPage
{
    StackLayout contextMenu;
    Button sortButton;
    Button clearSortButton;
    private bool isContextMenuDisplayed = false;
    private string currentColumnName;
    public MainPage()
    {
        InitializeComponent();
        CreateContextMenu();
        dataGrid.AllowSorting = true;
        dataGrid.GridTapped += DataGrid_GridTapped;           
     }
 
    private void DataGrid_GridTapped(object sender, GridTappedEventsArgs e)
    {
        relativeLayout.Children.Remove(contextMenu);
        isContextMenuDisplayed = false;
    }
 
    public void CreateContextMenu()
    {
        contextMenu = new StackLayout(); 
        sortButton = new Button();
        sortButton.Text = "Sort";           
        sortButton.BackgroundColor = Color.Black;
        sortButton.TextColor = Color.White;
        sortButton.Clicked += SortButton_Clicked;
        
        clearSortButton = new Button();
        clearSortButton.Text = "Clear sort";           
        clearSortButton.BackgroundColor = Color.Black;
        clearSortButton.TextColor = Color.White;
        clearSortButton.Clicked += ClearSortButton_Clicked;
 
        contextMenu.Children.Add(sortButton);
        contextMenu.Children.Add(clearSortButton);            
    }
 
    private void ClearSortButton_Clicked(object sender, EventArgs e)
    {
        relativeLayout.Children.Remove(contextMenu);
        isContextMenuDisplayed = false;
        dataGrid.SortColumnDescriptions.Clear();
    }
 
    private void SortButton_Clicked(object sender, EventArgs e)
    {
        relativeLayout.Children.Remove(contextMenu);
        isContextMenuDisplayed = false;
        dataGrid.SortColumnDescriptions.Clear();
        dataGrid.SortColumnDescriptions.Add(new SortColumnDescription()
        {
            ColumnName = currentColumnName
        });
    }
 
    public void DataGrid_GridLongPressed(object sender, GridLongPressedEventsArgs e)
    {
        if (!isContextMenuDisplayed)
        {
            currentColumnName = dataGrid.Columns[e.RowColumnindex.ColumnIndex].MappingName;
            var point = dataGrid.RowColumnIndexToPoint(e.RowColumnindex);
            relativeLayout.Children.Add(contextMenu, Constraint.Constant(point.X), Constraint.Constant(point.Y));
            isContextMenuDisplayed = true;
        }
        else
        {
            relativeLayout.Children.Remove(contextMenu);
            isContextMenuDisplayed = false;
        }
    }
}