How to Bind Static Class property to UI component in XAML / Xamarin - xaml

Question

In Xamarin application, I am not able to Bind the static property of the C# user defined static Class property (Colors.BackgroundColor) to XAML. I need to set the background of the color of grid by static value defined in static class.
But I am getting the error
Type UserInterfaceDefinitions not found in xmlns
on this XAML
BackgroundColor = "{Binding Source = {x:Static MyNamespace.Mobile:UserInterfaceDefinitions.Colors} }"
Static Class code
namespace MyNamespace.Mobile
{
public static class UserInterfaceDefinitions
{
public static class Colors
{
public static string BackgroundColor = "#DCECE";
}
}
}
XAML Code
<?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:buttons="clr-namespace:MyNamespace.Mobile.UI.Buttons"
xmlns:Status="clr-namespace:MyNamespace.Mobile.UI.StatusDetails"
x:Class="MyNamespace.Mobile.UI.TestAndDemoSelection">
<ContentPage.Content Margin="0,0,0,0" BackgroundColor="White">
<Grid x:Name="ChildGrid" Grid.Row="1" Grid.Column="0" ColumnSpacing="10" BackgroundColor="White" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<!-- I am getting the error as Type UserInterfaceDefinitions not found in xmlns-->
<BoxView Grid.Column="0" BackgroundColor = "{Binding Source = {x:Static MyNamespace.Mobile:UserInterfaceDefinitions.Colors} }" />
</Grid>
</ContentPage.Content>
</ContentPage>
Code Behind .cs
using MyNamespace.Mobile.UI.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace MyNamespace.Mobile.UI
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class TestAndDemoSelection : ContentPage
{
public TestAndDemoSelection()
{
InitializeComponent();
}
}
}
How to bind the static class property to XAML ?

Answer 1

I have got the resolutions. It was because of Nested Static class was not accessible inside the XAML the correct code as below.
user defined static class:
namespace MyNamespace.Mobile
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public static class UserInterfaceDefinitions
{
public static string BackgroundColor { get; } = "#DCECEC";
}
}
XAML file:
<?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:MyNamespace.Mobile"
x:Class="MyNamespace.Mobile.UI.TestAndDemoSelection">
<ContentPage.Content Margin="0,0,0,0" BackgroundColor="White">
<Grid x:Name="ChildGrid" Grid.Row="1" Grid.Column="0" ColumnSpacing="10" BackgroundColor="White" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<BoxView Grid.Column="0" BackgroundColor = "{Binding Source = {x:Static local:UserInterfaceDefinitions.BackgroundColor}}" />
</Grid>
</ContentPage.Content>
</ContentPage>

Answer 2

In order to bind on a Static Property:
1) Declare the namespace to import using xmlns
2) Use the xmlns accordingly in Source
=>
<?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:buttons="clr-namespace:MyNamespace.Mobile.UI.Buttons"
xmlns:Status="clr-namespace:MyNamespace.Mobile.UI.StatusDetails"
xmnlns:local="clr-namespace:MyNamespace.Mobile"
x:Class="MyNamespace.Mobile.UI.TestAndDemoSelection">
<ContentPage.Content Margin="0,0,0,0" BackgroundColor="White">
<Grid x:Name="ChildGrid" Grid.Row="1" Grid.Column="0" ColumnSpacing="10" BackgroundColor="White" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<BoxView Grid.Column="0" BackgroundColor = "{x:Static local:UserInterfaceDefinitions.Colors.BackgroundColor}" />
</Grid>
</ContentPage.Content>
</ContentPage>
Moreover, BackgroundColor should be a property in order to be accessible:
public static string BackgroundColor {get;} = "#DCECE";

Answer 3

XAML works very poorly with nested classes.
Yes, and in general, a public nested class is often a very bad technique.
Example:
namespace MyNamespace.Mobile
{
public static class Colors
{
public static string BackgroundColor { get; } = "Red";
}
}
XAML:
<StackPanel xmlns:Circassia.Mobile="clr-namespace:MyNamespace.Mobile"
Background ="{Binding Source={x:Static Circassia.Mobile:Colors.BackgroundColor}}"/>
Second example:
namespace MyNamespace.Mobile
{
public static class UserInterfaceDefinitions
{
public static ColorsClass Colors{ get; } = new ColorsClass();
public class ColorsClass
{
private static readonly string s_BackgroundColor = "Red";
public static string BackgroundColor { get; } = s_BackgroundColor;
}
}
}
XAML:
<StackPanel xmlns:Circassia.Mobile="clr-namespace:MyNamespace.Mobile"
Background ="{Binding BackgroundColor, Source={x:Static Circassia.Mobile:UserInterfaceDefinitions.Colors}}"/>