Display ContextMenu on LongPress for a View in xamarin forms - xamarin.forms

Question

Hi,
Could you please let me know how to display a context menu on long press effect.I have added a ListView with Effects but the context menu is not popping up after long pressing the listview.
MainPage.xaml
<ContentView x:Name="Parent" BackgroundColor="White" Padding="20" >
<dg:DataGrid ItemsSource="{Binding Data}" SelectionEnabled="True" RowHeight="70" HeaderHeight="50" BorderColor="#CCCCCC" HeaderBackground="#E0E6F8" ActiveRowColor="#8899AA">
<dg:DataGrid.Columns>
<dg:DataGridColumn Title="Logo" PropertyName="Logo" Width="50" SortingEnabled="False">
<dg:DataGridColumn.CellTemplate>
<DataTemplate>
<ListView x:Name="MainListView" local:LongPressedEffect.Command="{Binding ShowAlertCommand}" local:LongPressedEffect.CommandParameter="{Binding .}">
<ListView.Effects>
<local:LongPressedEffect />
</ListView.Effects>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.ContextActions>
<MenuItem Text="Add" ></MenuItem>
<MenuItem Text="Delete" ></MenuItem>
<MenuItem Text="Edit" ></MenuItem>
</ViewCell.ContextActions>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</DataTemplate>
</dg:DataGridColumn.CellTemplate>
</dg:DataGridColumn>
<dg:DataGridColumn Title="Team" PropertyName="Name" Width="2*" >
</dg:DataGridColumn>
<dg:DataGridColumn Title="Win" PropertyName="Win" Width="2*">
<dg:DataGridColumn.CellTemplate>
<DataTemplate>
<Picker x:Name="Fruits" Title="Fruits" HorizontalOptions="FillAndExpand">
<Picker.Items>
<x:String>Apple</x:String>
<x:String>Orange</x:String>
</Picker.Items>
</Picker>
</DataTemplate>
</dg:DataGridColumn.CellTemplate>
</dg:DataGridColumn>
<dg:DataGridColumn Title="Loose" PropertyName="Loose" Width="1*">
</dg:DataGridColumn>
<dg:DataGridColumn PropertyName="Home">
<dg:DataGridColumn.FormattedTitle>
<FormattedString>
<Span Text="Home" ForegroundColor="Black" FontSize="13" FontAttributes="Bold"/>
<Span Text=" (win-loose)" ForegroundColor="#333333" FontSize="11" />
</FormattedString>
</dg:DataGridColumn.FormattedTitle>
</dg:DataGridColumn>
<dg:DataGridColumn Title="Percentage" PropertyName="Percentage"/>
<dg:DataGridColumn Title="Streak" PropertyName="Streak" Width="0.7*"/>
</dg:DataGrid.Columns>
</ContentView>
LongPressedEffect.cs
public class LongPressedEffect : RoutingEffect
{
public LongPressedEffect() : base("MyApp.LongPressedEffect")
{
}
public static readonly BindableProperty CommandProperty = BindableProperty.CreateAttached("Command", typeof(ICommand), typeof(LongPressedEffect), (object)null);
public static ICommand GetCommand(BindableObject view)
{
return (ICommand)view.GetValue(CommandProperty);
}
public static void SetCommand(BindableObject view, ICommand value)
{
view.SetValue(CommandProperty, value);
}
public static readonly BindableProperty CommandParameterProperty = BindableProperty.CreateAttached("CommandParameter", typeof(object), typeof(LongPressedEffect), (object)null);
public static object GetCommandParameter(BindableObject view)
{
return view.GetValue(CommandParameterProperty);
}
public static void SetCommandParameter(BindableObject view, object value)
{
view.SetValue(CommandParameterProperty, value);
}
}
AndroidLongPressedEffect.cs
public class AndroidLongPressedEffect : PlatformEffect
{
private bool _attached;
/// <summary>
/// Initializer to avoid linking out
/// </summary>
public static void Initialize() { }
/// <summary>
/// Initializes a new instance of the
/// <see cref="T:Yukon.Application.AndroidComponents.Effects.AndroidLongPressedEffect"/> class.
/// Empty constructor required for the odd Xamarin.Forms reflection constructor search
/// </summary>
public AndroidLongPressedEffect()
{
}
/// <summary>
/// Apply the handler
/// </summary>
protected override void OnAttached()
{
//because an effect can be detached immediately after attached (happens in listview), only attach the handler one time.
if (!_attached)
{
if (Control != null)
{
Control.LongClickable = true;
Control.LongClick += Control_LongClick;
}
else
{
Container.LongClickable = true;
Container.LongClick += Control_LongClick;
}
_attached = true;
}
}
/// <summary>
/// Invoke the command if there is one
/// </summary>
/// <param name="sender">Sender.</param>
/// <param name="e">E.</param>
private void Control_LongClick(object sender, Android.Views.View.LongClickEventArgs e)
{
Console.WriteLine("Invoking long click command");
var command = LongPressedEffect.GetCommand(Element);
command?.Execute(LongPressedEffect.GetCommandParameter(Element));
}
/// <summary>
/// Clean the event handler on detach
/// </summary>
protected override void OnDetached()
{
if (_attached)
{
if (Control != null)
{
Control.LongClickable = true;
Control.LongClick -= Control_LongClick;
}
else
{
Container.LongClickable = true;
Container.LongClick -= Control_LongClick;
}
_attached = false;
}
}
}
Any help is very much appreciated!
Please let me know if more information is required.

Answer 1

You can set a property in App.cs as currentPage.
public static ContentPage currentPage;
And set it in the contentPage which contains your listView.
public xxxPage()
{
InitializeComponent();
App.currentPage = this;
}
And in LongPressedEffect.cs
public static ICommand GetCommand(BindableObject view)
{
//do something you want
App.currentPage.DisplayActionSheet("ActionSheet: Send to?", "Cancel", null, "Email", "Twitter", "Facebook");
return (ICommand)view.GetValue(CommandProperty);
}