Completed Event on a custom Entry - xamarin

I have two entries, one for username and the other for password.
<customEntry:EmailEntry Placeholder="Your email address" x:Name="Email" Keyboard="Email" WidthRequest="50" Text="{Binding UserName}"/>
<customEntry:PwdEntry Placeholder="Your password" x:Name="Password" IsPassword="true" Text="{Binding Password}"/>
The two entries (EmailEntry and PwdEntry) are of type ContentView not ContentPage. I am trying to get the Completed event on the EmailEntry but couldn't. Once the user hits the "Next" button on the keyboard, the focus should shift to PwdEntry.
If these were normal entries, I know that I can use,
Email.Completed += (object sender, EventArgs e) => Password.Focus();
As the two entries are ContentViews, I cannot change the focus to next entry as soon as the user hits "Next".
This is my CustomEntry...
<?xml version="1.0" encoding="UTF-8"?><ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="Ecommerce.Mobile.Core.EmailEntry"
xmlns:local="clr-namespace:Ecommerce.Mobile.Core.CustomViews"
xmlns:fr="clr-namespace:Ecommerce.Mobile.Core.Controls">
<ContentView.Content>
<fr:MyFrame CornerRadius="5"
OutlineColor="{StaticResource MocoWhite}"
BackgroundColor="Blue"
HasShadow="false" Padding="15,0">
<Grid ColumnSpacing="16">
<Grid.RowDefinitions>
<RowDefinition Height="50"/>
<RowDefinition Height="1"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid Grid.Column="0" Padding="0,10,0,0" HeightRequest="30" WidthRequest="20">
<Image Source="icons_envelope_white1x.png" HorizontalOptions="Start" />
</Grid>
<Grid Grid.Column="1" HeightRequest="65" WidthRequest="20">
<Label x:Name="HiddenLabel" Font="ProximaNovaRegular" FontSize="12" IsVisible="False" Margin="0" FontAttributes="Bold"/>
<fr:MyKeyboardEntry x:Name="EntryField" FontSize="15" TextColor="White" Keyboard="Email" ReturnType="Next" Text="{Binding Text, Mode=TwoWay}" PlaceholderColor="White" Margin="0,12,0,0"/>
</Grid>
</Grid>
</fr:MyFrame>
</ContentView.Content>
How can I achieve this?

As I could see you have a lot of nested components wrapped in your own class (a ViewCell in this case).
I bet eventually you'll have a base component, that provides the events you want to expose in your top-level component.
Let's take the Completed event, for example. Supposing you have the bellow structure:
- EmailEntry _inherites from_
└ MyKeyboardEntry _inherites from_
└ ...
└ Entry (provides the `Completed` event)
So you can subscribe and expose the event on each wrapper:
public class MyKeyboardEntry : View
{
...
// Expose the event
public event EventHandler<TextChangedEventArgs> TextChanged;
...
// Subscribe the original one with your own handler
public MyKeyboardEntry()
{
...
// Its your wrapped Entry object
entry.TextChanged += OnTextChanged;
...
}
...
// Implementing the #EvZ suggestion
public void TakeFocus()
{
entry.Focus();
}
...
// Finally, throw up your event notification
protected virtual void OnTextChanged(object sender, TextChangedEventArgs args)
{
... // Handle something if you need
TextChanged?.Invoke(this, args); // invoking the event this class owns using the C# 6 syntax
/*
// Using the C# <6
var hdlr = TextChanged;
if(hdlr != null)
hdlr.Invoke(this, args);
*/
}
...
}
Now you're able to handle the MyKeyboardEntry.TextChanged event outside the class.
You have to do this to each specific class that wraps another more generic (EmailEntry and so on).
I hope it helps.

Related

FindByName control inside another control on ContentPage in Xamarin

I want to set focus on SearchBar when he appears. The problem is that SearchBar is placed inside of popup view and I need to access him from ViewModel.
In standard way I would use
Xamarin.Forms.SearchBar tmp_SearchBar = this.Page.FindByName("fro_SearchBar_NewItem") as Xamarin.Forms.SearchBar;
but that's not working anymore.
Here is XAML
<sfPopup:SfPopupLayout x:Name="fro_Popup_NewItem" Opened="fro_Popup_NewItem_Opened" Grid.Row="1" HorizontalOptions="Center" VerticalOptions="Center" BackgroundColor="Black">
<sfPopup:SfPopupLayout.PopupView>
<sfPopup:PopupView BackgroundColor="Black" WidthRequest ="400" HeightRequest ="100" ShowFooter="False" ShowHeader="False">
<sfPopup:PopupView.ContentTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<!--Search bar-->
<Grid Grid.Row="0" HorizontalOptions="Center" VerticalOptions="Center">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<SearchBar x:Name="fro_SearchBar_NewItem"
Grid.Column="0"
Text="{Binding SearchText_Popup, Mode=TwoWay}"
SearchCommand="{Binding SearchCommand}"
Placeholder="Find"
CancelButtonColor="White"
TextColor="White"
PlaceholderColor="Gray"/>
</Grid>
</Grid>
</DataTemplate>
</sfPopup:PopupView.ContentTemplate>
</sfPopup:PopupView>
</sfPopup:SfPopupLayout.PopupView>
</sfPopup:SfPopupLayout>
Nested FindByName doesn't work either.
Syncfusion.XForms.PopupLayout.SfPopupLayout tmp_Popup = _Page.FindByName("fro_Popup_NewItem") as Syncfusion.XForms.PopupLayout.SfPopupLayout;
Xamarin.Forms.SearchBar tmp_SearchBar = tmp_Popup.FindByName("fro_SearchBar_NewItem") as Xamarin.Forms.SearchBar;
Thanks
You can use Task to open a new thread to complete this operation in code-behind.
Xaml:
<SearchBar x:Name="fro_SearchBar_NewItem" Placeholder="...." BackgroundColor="White"/>
Code behind:
public partial class PagePop : Popup
{
public PagePop()
{
InitializeComponent();
Task.Run(() => myTask());//Create and start the thread
}
private void myTask()
{
Thread.Sleep(300);
fro_SearchBar_NewItem.Focus();
}
}
It seems that this wasn't so far from right direction, neither of the comments actually.
Syncfusion.XForms.PopupLayout.SfPopupLayout tmp_Popup = _Page.FindByName("fro_Popup_NewItem") as Syncfusion.XForms.PopupLayout.SfPopupLayout;
Xamarin.Forms.SearchBar tmp_SearchBar = tmp_Popup.FindByName("fro_SearchBar_NewItem") as Xamarin.Forms.SearchBar;
but I found the one which works and I don't have to create separate XAML for Popup.
private void fro_Popup_NewItem_Opened(object sender, EventArgs e)
{
try
{
var nativeObject = (object)fro_Popup_NewItem.GetType().GetRuntimeProperties().FirstOrDefault(x => x.Name.Equals("NativeObject")).GetValue(fro_Popup_NewItem);
var formsPopupviewContentTemplate = nativeObject.GetType().GetRuntimeFields().FirstOrDefault(x => x.Name.Equals("formsPopupViewContentTemplate")).GetValue(nativeObject);
var SearchBar = (formsPopupviewContentTemplate as Grid).FindByName<SearchBar>("fro_SearchBar_NewItem");
SearchBar?.Focus();
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
}
Thanks for help, everyone.

How to return values from controls in popup and add them to the main page?

The main page has a button for adding new items. When the user presses it, a popup window appears.
I used this code for popup.xaml:
<xct:Popup xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="MReport.popup01"
xmlns:xct="http://xamarin.com/schemas/2020/toolkit"
Size="300,400">
<ScrollView>
<StackLayout Orientation="Vertical" Spacing="10">
<Label Text="From Time:" Padding="5,5,0,0" TextColor="Black"
HorizontalTextAlignment="Start" />
<TimePicker HorizontalOptions="Center" Time="00:00" />
<Label Text="To Time" Padding="5,5,0,0" TextColor="Black"
HorizontalTextAlignment="Start" />
<TimePicker HorizontalOptions="Center"/>
<Label Text="Your Activities:" Padding="5,5,0,0" TextColor="Black" />
<Editor x:Name="editor_value" VerticalOptions="CenterAndExpand" HeightRequest="200" />
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Button Grid.Column="1" Text="Add" Clicked="Button_Clicked_1" />
<Button Grid.Column="0" Text="Cancel" Clicked="Button_Clicked" />
</Grid>
</StackLayout>
</ScrollView>
</xct:Popup>
For popup.xaml.cs:
using Xamarin.CommunityToolkit.UI.Views;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace MReport
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class popup01 : Popup
{
public popup01()
{
InitializeComponent();
}
private void Button_Clicked(object sender, EventArgs e)
{
Dismiss("Cancelled");
}
private void Button_Clicked_1(object sender, EventArgs e)
{
}
}
}
For TabbedPage:
<?xml version="1.0" encoding="utf-8" ?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="MReport.TabbedMainPage">
<!--Pages can be added as references or inline-->
<ContentPage Title="New Report" IconImageSource="NewReport.png" BackgroundImageSource="blue_windows.jpg">
<StackLayout>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="10*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ScrollView>
<StackLayout>
<Label x:Name="lbl01" />
</StackLayout>
</ScrollView>
<Button Grid.Row="1" Text="Add New Item" Clicked="Button_Clicked"/>
</Grid>
<Button Grid.Row="1" Text="Send Report" />
</StackLayout>
</ContentPage>
<ContentPage Title="Report History" IconImageSource="History.png" BackgroundImageSource="blue_windows.jpg" />
<ContentPage Title="Messages" IconImageSource="Message.png" BackgroundImageSource="blue_windows.jpg"/>
</TabbedPage>
For TabbedPage.xaml.cs:
using Xamarin.Forms.PlatformConfiguration;
using Xamarin.Forms.PlatformConfiguration.AndroidSpecific;
using Xamarin.Forms.Xaml;
using Xamarin.CommunityToolkit.Extensions;
namespace MReport
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class TabbedMainPage : Xamarin.Forms.TabbedPage
{
public TabbedMainPage()
{
InitializeComponent();
On<Android>().SetToolbarPlacement(ToolbarPlacement.Bottom);
On<Android>().SetIsSmoothScrollEnabled(false);
}
private void Button_Clicked(object sender, EventArgs e)
{
Navigation.ShowPopup(new popup01());
}
}
}
I use CommunityToolKit for the popup.
The popup has two buttons. The ADD button will add the information entered in the popup to the main page.
I want the output to be like the image I've provided.
These frame boxes and their texts are added each time the user presses the add button in the popup. Those frame boxes are expanded based on the text volume inside them. What code should be written for the ADD button?
Please help me.
ShowPopupAsync can return a value to the caller
var result = await Navigation.ShowPopupAsync(popup);
whatever parameter is passed to Dismiss() will be returned to the caller

Virtual keyboard not working properly for Entry in TableView - [Android]

Description
I am using Entry in TableView and displaying the formatted value in focus. In this case virtual keyboard not showing while change focus within Entry.
Steps to Reproduce
Run the sample
Focus the 1st Entry
Focus 2nd Entry
Unfocus both views
Focus 2st Entry. See the keyboard not showing.
Sometimes while unfocus both Entry, keyboard not getting collapsed.
Basic Information
Version with issue: 4.8.0.1451
Platform Target Frameworks:
Android: Nexus 6 Marshmallow 6.0 - API 23 emulator.
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="EntryWithTableView.MainPage">
<TableView>
<TableRoot>
<TableSection >
<ViewCell >
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Entry Keyboard="Numeric" Focused="entry1_Focused" Unfocused="entry1_Unfocused"
x:Name="entry1" Grid.Column="1" WidthRequest="100"/>
<Entry Keyboard="Numeric" Focused="entry1_Focused" Unfocused="entry1_Unfocused"
Grid.Column="2" x:Name="entry2" WidthRequest="100"/>
</Grid>
</ViewCell>
</TableSection>
</TableRoot>
</TableView>
</ContentPage>
[C#]:
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
}
double value = 5;
private void entry1_Focused(object sender, FocusEventArgs e)
{
Entry entry = sender as Entry;
if(entry != null)
{
entry.Text = value.ToString();
}
}
private void entry1_Unfocused(object sender, FocusEventArgs e)
{
Entry entry = sender as Entry;
if (entry != null)
{
entry.Text = value.ToString("F");
}
}
}
It caused by the TableView . You could use Grid as the root layout directly .
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Entry Keyboard="Numeric" Focused="entry1_Focused" Unfocused="entry1_Unfocused"
x:Name="entry1" Grid.Column="1" WidthRequest="100" />
<Entry Keyboard="Numeric" Focused="entry1_Focused" Unfocused="entry1_Unfocused"
Grid.Column="2" x:Name="entry2" WidthRequest="100"/>
</Grid>
If you want to display a collection , you could use ListView .

Get the click command from template to the view model in xamarin

In the template there is a button and created as below called x:Name="cartbutton"
<?xml version="1.0" encoding="UTF-8"?>
<Grid xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:ffimageloading="clr-namespace:FFImageLoading.Forms;assembly=FFImageLoading.Forms"
x:Class="FormsApplication.Templates.ListItemTemplate"
xmlns:controls="clr-namespace:FormsControls.Base;assembly=FormsControls.Base"
ColumnSpacing="0" RowSpacing="0" HeightRequest="350" Padding="8,0,8,8" x:Name="ListItemTempPage">
<Grid.RowDefinitions>
<RowDefinition Height="300" />
<RowDefinition Height="30" />
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<controls:RoundedBoxView Grid.RowSpan="2" BackgroundColor="White" BorderColor="Silver" CornerRadius="8" BorderThickness="2"/>
<ffimageloading:CachedImage Grid.RowSpan="2" Source="{Binding ImageSource}" Aspect="AspectFill" DownsampleToViewSize="False"/>
<Button x:Name="cartbutton" Grid.Row="0" HorizontalOptions="End" VerticalOptions="Start" Image="lowim.png" BackgroundColor="Transparent" Margin="0,5,5,0" Command="{Binding ParentContext.Itemtapped, Source={x:Reference ListItemTempPage}}" CommandParameter="{Binding .}"/>
</Grid>
and the parent page called by the reference the template as below
<ListView x:Name="listView" Grid.Row="1" Margin="0,8,0,0"
HasUnevenRows="true" ItemsSource="{Binding FoodItems}"
SeparatorColor="Transparent" SeparatorVisibility="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<templates:ListItemTemplate ParentContext="{Binding BindingContext, Source={x:Reference ListItemPage}}"/>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
<ListView.Behaviors>
<controls:EventToCommandBehavior EventName="ItemTapped" Command="{Binding ListItemTappedCommand}" CommandParameter="{x:Reference listView}"/>
</ListView.Behaviors>
</ListView>
finally the viewmodel goes with the icommand as below
public SelectItemViewModel(IAppContext context, IRestService restService) : base(context)
{
_restService = restService;
Title = "Category Products";
ListItemTappedCommand = new Command<ListView>(OnListItemTappedCommand);
PageAppearingCommand = new Command(OnPageAppearingCommand);
Itemtapped = new Command(OnItemtapped);
}
public ICommand Itemtapped { get; }
private void OnItemtapped()
{
Navigator.PushAsync<SelectItemViewModel>();
}
so the probelm is when compiling there is an error saying that
No property, bindable property, or event found for 'ParentContext', or mismatching type between value and property.
so basically saying that i am unable to give the button command ( in the template page) to trigger in the viewmodel properly, help will be appreciated to figure this out, thanks.
I'd introduce a AddToCartCommand in your child control, which is invoked if the button is clicked.
// in your ListItemTemplate.xaml.cs
public static BindableProperty AddToCartCommandProperty = BindableProperty.Create(/* ... */);
public ICommand AddToCartCommand
{
get => (ICommand)GetValue(AddToCartCommandProperty);
set => SetValue(AddToCartCommandProperty, value);
}
public void Button_OnClick(object sender, EventArgs e)
{
this.AddToCartCommand?.Execute(null);
}
To bind to this from your parent view, you'll need a reference to that parent view with x:Name="Page" (or however you'd like to name your page) and then use a {Binding Source={x:Reference Page}, Path=BindingContext.Itemtapped}
<ContentPage ... x:Name="Page"> <!-- I have elided attributes that are not relevant to my answer -->
<!-- Elided -->
<ListView ...>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<templates:ListItemTemplate AddToCartCommand="{Binding Source={x:Reference Page}, Path=BindingContext.Itemtapped}" />
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
<!-- Elided -->
</ListView>
<!-- Elided -->
</ContentPage>

Can't bind ListView to ViewModel

This my ViewModel:
namespace DietAndFitness.ViewModels
{
public class FoodItemsViewModel
{
private SQLiteAsyncConnection database;
public static ObservableCollection<GlobalFoodItem> FoodItems { get; set; }
public FoodItemsViewModel(SQLiteAsyncConnection _database)
{
database = _database;
}
public async void LoadList()
{
FoodItems = new ObservableCollection<GlobalFoodItem>(await database.Table<GlobalFoodItem>().ToListAsync());
}
public void Add()
{
FoodItems.Add(new GlobalFoodItem("Item"));
}
}
}
I want to bind an instance of this VM to the list in my View but I just can't get it to work properly. The only thing I've managed to get to work is this:
<?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:DietAndFitness.ViewModels"
x:Class="DietAndFitness.Views.FoodDatabasePage">
<ContentPage.Content>
<StackLayout>
<ListView ItemsSource="{Binding FoodItems}" RowHeight="120">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ContentView Padding="5">
<Frame OutlineColor="Accent" Padding="10">
<StackLayout>
<Grid HorizontalOptions="Center">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Label Text="{Binding Name}" FontSize="22" VerticalOptions="CenterAndExpand" HorizontalOptions="Center" Grid.Row="0" Grid.Column="0"/>
<Label Text="{Binding Calories}" FontSize="22" VerticalOptions="CenterAndExpand" HorizontalOptions="Center" Grid.Row="0" Grid.Column="1"/>
</Grid>
<Grid HorizontalOptions="Center">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Label Text="Carbohydrates" Grid.Row="1" Grid.Column="0" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="16"/>
<Label Text="Proteins" Grid.Row="1" Grid.Column="1" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="16"/>
<Label Text="Fats" Grid.Row="1" Grid.Column="2" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="16"/>
<Label Text="{Binding Carbohydrates}" Grid.Row="2" Grid.Column="0" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="16"/>
<Label Text="{Binding Proteins}" Grid.Row="2" Grid.Column="1" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="16"/>
<Label Text="{Binding Fats}" Grid.Row="2" Grid.Column="2" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" FontSize="16"/>
</Grid>
</StackLayout>
</Frame>
</ContentView>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<Grid HorizontalOptions="Center">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Button x:Name="AddFoodItemButton" BackgroundColor="LightGray" HorizontalOptions="CenterAndExpand" Text="Add" Grid.Row="0" Grid.Column="0" Clicked="AddFoodItemButton_Clicked" />
<Button x:Name="EditFoodItemButton" BackgroundColor="LightGray" HorizontalOptions="CenterAndExpand" Text="Edit" Grid.Row="0" Grid.Column="1" />
<Button x:Name="DeleteFoodItemButton" BackgroundColor="LightGray" HorizontalOptions="CenterAndExpand" Text="Delete" Grid.Row="0" Grid.Column="2" />
</Grid>
</StackLayout>
</ContentPage.Content>
But this has problems too:
If I create the VM in the page constructor the list won't load unless I refresh the page
If I create the VM inside App.cs the list will load on the first try but then I can't seem to access the instance of the VM
How do I bind my ListView to this VM? And is it possible to do so without making my ObservableCollection static?
I'm using a Master-Detail page in my app if it makes any difference (this is one of the detail pages).
Edit: Here is what I did in the constructor. SQLiteConnection.Database is just a static class that contains the connection to the database.
public FoodDatabasePage ()
{
FoodDatabase = new FoodItemsViewModel(SQLiteConnection.Database);
FoodDatabase.LoadList();
InitializeComponent ();
}
There's a few things that you have there.
When binding a ViewModel usually it's against the whole Page making the ViewModel its BindingContext specially in cases like yours when you have methods that want to access later.
So to do this you will need a few changes.
Your Page 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"
xmlns:local="clr-namespace:DietAndFitness.ViewModels"
x:Class="DietAndFitness.Views.FoodDatabasePage">
<ContentPage.Content>
<StackLayout>
<ListView ItemsSource="{Binding FoodItems}"
RowHeight="120">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Frame OutlineColor="Accent" Padding="15">
<StackLayout>
<Grid HorizontalOptions="Center">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Label Text="{Binding Name}"
FontSize="22"
VerticalOptions="CenterAndExpand"
HorizontalOptions="Center"
Grid.Row="0"
Grid.Column="0"/>
</Grid>
</StackLayout>
</Frame>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</StackLayout>
</ContentPage.Content>
</ContentPage>
Check that I changed the ListView ItemSource for the name of the collection in your FoodItemsViewModel.
Also, part of your XAML disappeared so I could not complete it.
Your Code Behind class: (FoodDatabasePage.xaml.cs)
public FoodItemsViewModel FoodDatabase {get; set;}
public FoodDatabasePage ()
{
InitializeComponent ();
FoodDatabase = new FoodItemsViewModel(SQLiteConnection.Database);
BindingContext = FoodDatabase;
}
public override void OnAppearing()
{
FoodDatabase.LoadList();
}
Here is where the "magic" happens. We are creating and storing the object of our FoodItemsViewModel so you can access it later as you need and then we are setting this object recently created as the BindingContext of the page (as explained above). Setting the ViewModel as the BindingContext of Page the latter will be able to access any public property of the FoodItemsViewModel.
Also, you will notice the LoadList() method was removed from the constructor, this is because there shouldn't be any heavy transaction (actually we should avoid any transactions) in the Page constructor. We moved it instead to the OnAppearing callback method that is executed by the Page when this is about to be displayed.
Note: This method is called every time the Page is presented on the screen so if you navigate away and come back it will be called again.
Your ViewModel:
namespace DietAndFitness.ViewModels
{
public class FoodItemsViewModel
{
private SQLiteAsyncConnection database;
//You don't need it static
public ObservableCollection<GlobalFoodItem> FoodItems { get; set; }
public FoodItemsViewModel(SQLiteAsyncConnection _database)
{
database = _database;
}
public async void LoadList()
{
// separated it only for readability.
var items = await database.Table<GlobalFoodItem>().ToListAsync();
FoodItems = new ObservableCollection<GlobalFoodItem>(items);
}
public void Add()
{
FoodItems.Add(new GlobalFoodItem("Item"));
}
}
}
This remains almost the same. The only change was removing the static qualifier to the FoodItems property since it does not need it anymore.
The above is just the basic of Mvvm and DataBinding. There're a few other things that you will need to take into consideration like INotifiedPropertyChanged, Commands and other important things.
You can find more information regarding this here
Hope this helps.-
PS: I couldn't check all of your code for any error.

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