/// <summary>
/// Returns true if parameter has a value that can lead to a holder.
/// </summary>
/// <param name="parameter">
/// Could be a container id (<c>string</c>), container (<see cref="ItemsControl"/>), or holder (<see cref="ContentControl"/>).
/// </param>
/// <returns></returns>
public bool CanExecute(object parameter)
{
try
{
var holder = GetHolder(parameter);
if (holder == null)
{
return(true);
}
return(!MvxContainer.GetHasClosingAction(holder));
}
catch (Exception)
{
}
return(true);
}
internal static ContentControl GetHolder(object parameter)
{
var container = parameter as ItemsControl;
ContentControl holder = null;
if (container == null && parameter is string id)
{
container = MvxContainer.GetContainerById(id);
}
if (container != null && container.Items.Count > 0)
{
if (container is Selector selector)
{
holder = selector.SelectedItem as ContentControl;
}
holder = container.Items[container.Items.Count - 1] as ContentControl;
}
if (holder == null)
{
holder = parameter as ContentControl;
}
return(holder);
}
/// <summary>
/// Execute a close command on a holder.
/// </summary>
/// <param name="parameter">
/// Could be a container id (<c>string</c>), container (<see cref="ItemsControl"/>), or holder (<see cref="ContentControl"/>).
/// </param>
/// <remarks>
/// If the parameter is <see cref="string"/>, the command will search for the container of same id
/// and if the parameter is <see cref="ItemsControl"/> it will use it as a container.
/// In both cases the command will get the selected holder in the container (if it is a <see cref="Selector"/>)
/// or it will use the last holder in the items collection.
/// The close command is will close all the views in the holder navigation stack.
/// </remarks>
public async void Execute(object parameter)
{
var holder = MvxCloseViewCommand.GetHolder(parameter);
if (holder == null)
{
throw new InvalidCastException("Command parameter should be a content control.");
}
var history = MvxContainer.GetHolderHistory(holder);
if (history != null)
{
MvxContainer.SetHasClosingAction(holder, true);
RaiseCanExecuteChanged();
var nav = Mvx.Resolve <IMvxNavigationService>();
foreach (var mv in history.Select((c) => MvxWpfPresenter.GetViewModel(c)).ToList())
{
await nav.Close(mv);
}
MvxContainer.SetHasClosingAction(holder, false);
RaiseCanExecuteChanged();
}
}
/// <summary>
/// Execute a back command on a holder.
/// </summary>
/// <param name="parameter">
/// Could be a container id (<c>string</c>), container (<see cref="ItemsControl"/>), or holder (<see cref="ContentControl"/>).
/// </param>
/// <remarks>
/// If the parameter is <see cref="string"/>, the command will search for the container of same id
/// and if the parameter is <see cref="ItemsControl"/> it will use it as a container.
/// In both cases the command will get the selected holder in the container (if it is a <see cref="Selector"/>)
/// or it will use the last holder in the items collection.
/// The back command is actually a close command for the last view in the holder.
/// </remarks>
public void Execute(object parameter)
{
var holder = GetHolder(parameter);
if (holder == null)
{
return;
}
var view = holder.Content as FrameworkElement;
if (view == null)
{
return;
}
object vm = null;
if (view is MvvmCross.Views.IMvxView mvxv)
{
vm = mvxv.ViewModel;
}
if (vm == null)
{
vm = view.DataContext;
}
if (vm == null)
{
return;
}
MvxContainer.SetHasClosingAction(holder, true);
RaiseCanExecuteChanged();
var nav = Mvx.Resolve <Navigation.IMvxNavigationService>();
nav.Close(vm as ViewModels.IMvxViewModel);
MvxContainer.SetHasClosingAction(holder, false);
RaiseCanExecuteChanged();
}