Xamarin.Forms MasterDetailPage dismiss MasterPageItem

Question

I have a MasterDetailPage and I have sidebar menu? with MasterPageItem. Now I am trying to dismiss the presented MasterPageItem. How would I do this?

Here is my MasterDetailPage:

<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms" 
                  xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
                  xmlns:local="clr-namespace:MyApp;assembly=MyApp"
                  x:Class="MyApp.MainPage">
  <MasterDetailPage.Master>
    <local:MasterPage x:Name="masterPage" />
  </MasterDetailPage.Master>
    <MasterDetailPage.Detail>
        <NavigationPage>
            <x:Arguments>
                <local:HomePage />
            </x:Arguments>
        </NavigationPage>
    </MasterDetailPage.Detail>
</MasterDetailPage>

and the OnItemSelected method:

void OnItemSelected(object sender, SelectedItemChangedEventArgs e)
        {
            var item = e.SelectedItem as MasterPageItem;
            if (item != null)
            {

                if(item.Title == "Logout")
                {
                    SecureStorage.RemoveAll();
                    MessagingCenter.Send<Paindown.App>((Paindown.App)Xamarin.Forms.Application.Current, "UpdateMenu");
                    IsPresented = false;
                }
                else
                {
                    Detail = new NavigationPage((Page)Activator.CreateInstance(item.TargetType));
                    masterPage.listView.SelectedItem = null;
                    IsPresented = false;
                }
            }
        }

Here is how I am defining a page in my sidebar menu in MasterPage:

menu.Add(new MasterPageItem
                {
                    Title = "Login",
                    TargetType = typeof(LoginPage)
                });

My question is from LoginPage, how do I go back to HomePage?

Answer 1

You could use MessageCenter send message from LoginPage to MenuPage, then can make the MenuPage set the selected item be HomePage.

For example, send message from LoginPage:

void Button_Clicked(object sender, EventArgs e)
{
    //MenuItemType.HomePage is a int value to represent the HomePage
    MessagingCenter.Send<object, int>(this, "Home", (int)MenuItemType.HomePage);
}

Then in MenuPage can set the current page be HomePage:

public partial class MenuPage : ContentPage
{
    public MenuPage()
    {
       ...

       //ListViewMenu is the name of ListView in Slider menu
       //menuItems is the ViewModel which contains the HomePage

       MessagingCenter.Subscribe<object,int>(this, "Home", (senders,arg) =>
        {
            ListViewMenu.SelectedItem = menuItems[arg];
        });

       ...
    }

}  

=================================Update================================

If want a amimation for this, you need to open the slider menu and close it manually.

Before that, we could create a public static Instance of MainPage(MasterDetailPage). Then we can use it in MenuPage to use IsPresented property.

MainPage:

public partial class MainPage : MasterDetailPage
{
  ...
  public static MainPage Instance { set; get; }

  ...

  public MainPage()
  {
   ...
   Instance = this;
   ..
  
  }
}

Then MenuPage will modify the previous method of MessagingCenter.Subscribe as follows:

...
MessagingCenter.Subscribe<object,int>(this, "Home",async (senders,arg) =>
{
    // open slider menu
    MainPage.Instance.IsPresented = true;
    // set selected item
    ListViewMenu.SelectedItem = menuItems[arg];
    // wait 0.5 second
    await Task.Delay(500);
    //close slider menu
    MainPage.Instance.IsPresented = false;
});
...