Xamarin Get ListItem Context - xamarin

Question

I've got a user control that I'm including in a ListView and I want to add dynamic content when the user control initialises based on the listitem binding. I'm not sure how to do this. See the "HOW DO I BIND THIS???"... I presume I should binding my PropertyBinding to the listitem somehow?
Here's my original view with my listview
<?xml version="1.0" encoding="UTF-8"?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:local="clr-namespace:EngineerApp" x:Class="EngineerApp.GigsPage" NavigationPage.HasNavigationBar="false" xmlns:controls="clr-namespace:XLabs.Forms.Controls;assembly=XLabs.Forms">
<ContentPage Title="Gigs" Icon="icon.png">
<StackLayout Orientation="Vertical">
<local:HeaderBar LeftButtonText="Back" RightButtonText="Leave" LeftButtonClickEvent="Back" RightButtonClickEvent="Back"></local:HeaderBar>
<local:ButtonBar LeftButtonText="Add Gig" RightButtonText="Month View" LeftButtonClickEvent="AddGig" RightButtonClickEvent="Back"></local:ButtonBar>
<ActivityIndicator IsRunning="{Binding IsBusy}" IsVisible="{Binding IsBusy}"></ActivityIndicator>
<ListView HasUnevenRows="true" SeparatorVisibility="Default" ItemsSource="{Binding gigs}" ItemSelected="Handle_ItemSelected">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Frame Padding="20,20,20,20">
<Frame.Content>
<Frame Padding="15,15,15,15" OutlineColor="Gray" BackgroundColor="White">
<Frame.Content>
<StackLayout Padding="20,0,0,0" Orientation="Vertical" HorizontalOptions="CenterAndExpand">
<Label Text="{Binding venue}"
HorizontalTextAlignment="Center"
TextColor="#69add1"/>
<Label Text="{Binding date}"
HorizontalTextAlignment="Center"
FontFamily="OpenSans-Light"
FontSize="9"
TextColor="#69add1"/>
<local:AuthorisationBar SelectedGig="{Binding .}"></local:AuthorisationBar>
</StackLayout>
</Frame.Content>
</Frame>
</Frame.Content>
</Frame>
</ViewCell>
<local:GigCard />
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentPage>
</TabbedPage>
And then here's the user control xaml.
<?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="EngineerApp.AuthorisationBar">
<ContentView.Content>
<StackLayout BackgroundColor="Red" HeightRequest="50" x:Name="barcontent" Orientation="Horizontal" HorizontalOptions="FillAndExpand">
<Label HorizontalOptions="FillAndExpand" VerticalOptions="Center" Text="I want to show some data here once the bindings are working"></Label>
</StackLayout>
</ContentView.Content>
</ContentView>
And here's the code behind for the user control
using System;
using System.Collections.Generic;
using EngineerApp.ViewModels;
using Xamarin.Forms;
namespace EngineerApp
{
public partial class AuthorisationBar : ContentView
{
public static readonly BindableProperty GigProperty = BindableProperty.Create("SelectedGig", typeof(GigViewModel), typeof(AuthorisationBar), new GigViewModel());
public GigViewModel SelectedGig
{
get
{
return (GigViewModel)GetValue(GigProperty);
}
set
{
SetValue(GigProperty, value);
}
}
public AuthorisationBar()
{
InitializeComponent();
BindingContext = this;
}
}
}
UPDATE 1 - Updated all pages to reflect most recent suggestion. With the {Binding .} I now get the error stated below:
"Cannot assign property "SelectedGig": Property does not exists, or is not assignable, or mismatching type between value and property"

Answer 1

Try this:
<local:AuthorisationBar SelectedGig="{Binding .}"></local:AuthorisationBar>
where "." will be the "current" item of the list.
Notice I used SelectedGid in my code as this is the name of the property you defined your custom control, not SelectedGigId.
Also you need to remove this line from the constructor of your custom control:
BindingContext = SelectedGig;
The BindingContext will already be of type GigViewModel
Hope this helps!
UPDATE
Your Custom Control code behind should look:
public partial class AuthorisationBar : ContentView
{
public AuthorisationBar()
{
InitializeComponent();
}
public static readonly BindableProperty SelectedGigProperty = BindableProperty.Create(nameof(SelectedGig), typeof(GigViewModel), typeof(AuthorisationBar), null);
public GigViewModel SelectedGig
{
get
{
return (GigViewModel)GetValue(SelectedGigProperty);
}
set
{
SetValue(SelectedGigProperty, value);
}
}
}
As previously stated you don't need to set anything to the BindingContext
UPDATE 2
In response to your question. The error was that the BindableProperty of your custom control was not complying with the naming conventions requirements.
From Xamarin BindableProperty documentation:
The naming convention for bindable properties is that the bindable property identifier must match the property name specified in the Create method, with "Property" appended to it.
This is why updating your BindableProperty from GigProperty to SelectedGigProperty fixed your issue.

Answer 2

I've done something similar for my current project - passing the current item's ID to my ViewModel (from the code you've posted, it seems you're not using proper separation of concerns under the MVVM paradigm - the VM shouldn't be initialising anything in your view):
<Button Text="Reconnect" Command="{Binding Path=BindingContext.ReconnectCommand, Source={x:Reference Name=ServicesList}}" CommandParameter="{Binding}" VerticalOptions="Center"/>
For reference, the button which is passing the command is embedded in a ListView.DataTemplate, and is passing the ID of the list item it's part of