Code Behind Xamarin forms launch a function in another page - xaml

Question

I have 2 ContentView in MyWordPage.Xaml which are MyWordListView and AddWordsView
My MyWordPage.Xaml looks like this :
<ContentView x:Name="MyWordListView" >
<CollectionView x:Name="ListOfWords" IsVisible="False"
SelectionMode="Single" >
<CollectionView.ItemsLayout>
<LinearItemsLayout Orientation="Vertical" />
</CollectionView.ItemsLayout>
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout >
<Label Text="{Binding .}" />
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</ContentView>
<ContentView IsVisible="False" x:Name="AddWordsView" />
<pv:PancakeView HorizontalOptions="End" VerticalOptions="End" Margin="0,0,10,150" Padding="10" CornerRadius="10">
<Image HeightRequest="30" WidthRequest="30" Aspect="AspectFit" />
<pv:PancakeView.GestureRecognizers>
<TapGestureRecognizer Tapped="OnChangeViewButton" />
</pv:PancakeView.GestureRecognizers>
</pv:PancakeView>
<Grid/>
If MyWordListView is visible, AddWordsView is not visible and vise versa.
The App starts with MyWordListPage visible and MyWordPage.xaml.cs looks like this:
public MyWordPage()
{
InitializeComponent();
// My second content view AddWordsView take content form a content page
// this content page name is MyAddWordPage
AddWordsView.Content = new MyAddWordPage().Content;
//My list of words
ListOfWords.ItemsSource = new List<string>()
{
"New York",
"London",
"Mumbai",
"Chicago"
};
}
//I navigate between the 2 View With an Overlay Button that make
//each one of View visible thanks to a boolean
bool ViewChange=false;
void OnChangeViewButton(System.Object sender, System.EventArgs e)
{
if (ViewChange==false)
{
AddWordsView.IsVisible=true;
MyWordListView.IsVisible=false;
ViewChange=!ViewChange;
}
else
{
AddWordsView.IsVisible=false;
MyWordListView.IsVisible=true;
ViewChange=!ViewChange;
}
}
OnUpdateMyList()
{
// Here I do things to refresh my list
}
MyAddWordPage.xaml.cs looks like this :
public MyWordPage()
{
InitializeComponent();
}
void OnInsertWord(System.Object sender, System.EventArgs e)
{
}
What I would like to do :
In MyAddWordPage.xaml.cs when clicking on a button to launch the function OnInsertWord() I would like to launch the function OnUpdateMyList() in MyWordPage.xaml.cs in order to refresh My collectionView in MyWordListView
Thanks for your help

Answer 1

According to your requirement, you can achieve this by overriding OnAppearing method.
The OnAppearing method is executed after the ContentPage is laid out, but just before it becomes visible.So, you can rebind the list to the collectionview in this method. Therefore, this is a good place to set the content of Xamarin.Forms views.
Here is the code in MyWordPage.xaml.cs:
public MainPage()
{
InitializeComponent();
// My second content view AddWordsView take content form a content page
// this content page name is MyAddWordPage
AddWordsView.Content = new MyAddWordPage().Content;
//My list of words
}
//Create a list
List<string> list = new List<string>()
{
"New York",
"London",
"Mumbai",
"Chicago"
};
protected override void OnAppearing()
{
base.OnAppearing();
ListOfWords.ItemsSource = list;
}
//I navigate between the 2 View With an Overlay Button that make
//each one of View visible thanks to a boolean
bool ViewChange = false;
void OnChangeViewButton(System.Object sender, System.EventArgs e)
{
if (ViewChange == false)
{
AddWordsView.IsVisible = true;
MyWordListView.IsVisible = false;
ViewChange = !ViewChange;
}
else
{
AddWordsView.IsVisible = false;
MyWordListView.IsVisible = true;
ViewChange = !ViewChange;
}
}
}
Here is the code in MyWordPage.Xaml:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="App5.MainPage">
<StackLayout>
<StackLayout x:Name="MyWordListView">
<CollectionView x:Name="ListOfWords" SelectionMode="Single" >
<CollectionView.ItemsLayout>
<LinearItemsLayout Orientation="Vertical" />
</CollectionView.ItemsLayout>
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout >
<Label Text="{Binding .}" />
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
<ContentView IsVisible="False" x:Name="AddWordsView" >
<Label Text="Here is the text."></Label>
</ContentView>
<StackLayout>
<Button Clicked="OnChangeViewButton"></Button>
</StackLayout>
</StackLayout>
</ContentPage>