Binding in Code Behind with Master/Detail Template - xamarin

Question

I've generated a Master/Detail view app (via Master Detail template of Xamarin, Visual Studio 2019) and I'm trying to perform data binding in Code Behind instead of XAML in the Detail view in order to retrieve and show the "Description" entry:
Therefore I modified my ItemDetailPage.xaml as follows (commented out the section):
<?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="MDDummy.Views.ItemDetailPage"
Title="{Binding Title}">
<!--
<StackLayout Spacing="20" Padding="15">
<Label Text="Text:" FontSize="Medium" />
<Label Text="{Binding Item.Text}" FontSize="Small"/>
<Label Text="Description:" FontSize="Medium" />
<Label Text="{Binding Item.Description}" FontSize="Small"/>
</StackLayout>
-->
</ContentPage>
In the code behind ItemDetailPage.xaml.cs I inserted the following:
namespace MDDummy.Views
{
public partial class ItemDetailPage : ContentPage
{
ItemDetailViewModel viewModel;
public ItemDetailPage(ItemDetailViewModel viewModel)
{
InitializeComponent();
BindingContext = this.viewModel = viewModel;
var layout = new StackLayout
{
Spacing = 40,
Padding = new Thickness(20, 20, 20, 20),
Orientation = StackOrientation.Horizontal
};
var testLabel = new Label();
testLabel.SetBinding(Label.TextProperty, "Description");
testLabel.BindingContext = new {Description = "{Binding Item.Description}"};
layout.Children.Add(testLabel);
Content = layout;
}
}
}
in order to show the "Description" entry via Data Binding. However other than in the xaml file I can't seem to access the related data entry, here "Description" from the Models folder Items.cs
namespace MDDummy2.Models
{
public class Item
{
public string Id { get; set; }
public string Text { get; set; }
public string Description { get; set; }
}
}
and MockDataStore.cs (where the Description entry is located I intend to display in the Detail view).
How can I access the data field, for instance "Description" in code behind in order to show it in the Detail view? Your help is greatly appreciated!

Answer 1

What is the ItemDetailViewModel? You set Label text binding by testLabel.BindingContext = new {Description = "{Binding Item.Description}"};I think it is mistake.
I do one sample about using binding by code behind, you can take a look:
public partial class Page8 : ContentPage
{
private ItemDetailViewModel viewmodel;
public Page8()
{
InitializeComponent();
viewmodel = new ItemDetailViewModel()
{
item = new Item() { Id = "1", Text = "this is item1", Description = "item class description" },
m1 = new model1() {Id="2",Text="this is model1",Description="model1 class description." }
};
var layout = new StackLayout
{
Spacing = 40,
Padding = new Thickness(20, 20, 20, 20),
Orientation = StackOrientation.Horizontal
};
var testLabel = new Label();
testLabel.SetBinding(Label.TextProperty, new Binding("Description",source:viewmodel.item) );
layout.Children.Add(testLabel);
var testLabel1 = new Label();
testLabel1.SetBinding(Label.TextProperty, new Binding("Description",source:viewmodel.m1));
layout.Children.Add(testLabel1);
Content = layout;
this.BindingContext = viewmodel;
}
}
public class Item
{
public string Id { get; set; }
public string Text { get; set; }
public string Description { get; set; }
}
public class model1
{
public string Id { get; set; }
public string Text { get; set; }
public string Description { get; set; }
}
public class ItemDetailViewModel
{
public Item item { get; set; }
public model1 m1 { get; set; }
}