Bindings for Properties inside the RadGauge GaugeRangesDefinition and GradientStop Classes

Environment

Product	Version	Author
Gauge for .NET MAUI	7.1.0	Dobrinka Yordanova

Description

When using a horizontal or vertical Gauge in a .NET MAUI application, you may want to bind the values for the offset, the color properties inside the RadGradientStop, or the values for the StartThickness and EndThickness for the GaugeRangesDefinition. This article demonstrates how to set bindings for the properties inside the GaugeRangesDefinition and RadGradientStop classes.

This KB article also answers the following questions:

• How can I set bindings for the Offset and Color properties inside the RadGradientStop?
• How can I set bindings for the StartThickness and EndThickness properties inside the GaugeRangesDefinition?

Solution

The properties inside the GaugeRangesDefinition and RadGradientStop classes are not bindable. To apply binding, use an attached property.

The example shows how to apply binding for the StartThickness property inside the GaugeRangesDefinition. The approach is applicable for the other properties.

1. Define the RadGauge in XAML:

<VerticalStackLayout>
    <Label Text="{Binding Value, Source={x:Reference slider}}"/>
    <Slider Value="{Binding Data, Mode=TwoWay}" x:Name="slider" Minimum="5" Maximum="40"/>

    <telerik:RadVerticalGauge x:Name="gauge">
        <telerik:RadVerticalGauge.Axis>
            <telerik:GaugeLinearAxis LabelPosition="Start"
            Maximum="1"
            Minimum="-1"
            Step="0.5" />
        </telerik:RadVerticalGauge.Axis>
        <telerik:RadVerticalGauge.Indicators>
            <telerik:GaugeShapeIndicator Value="0" />
        </telerik:RadVerticalGauge.Indicators>
        <telerik:RadVerticalGauge.Ranges>
            <telerik:GaugeRangesDefinition x:Name="range"
                                           local:TelerikUtils.MyThickness="{Binding Data}">
                <telerik:GaugeGradientRange From="-1" To="1">
                    <telerik:RadGradientStop
                    x:Name="B"
                    Offset="1"
                    Color="Blue" />
                    <telerik:RadGradientStop
                    x:Name="R"
                    Offset="0"
                    Color="Red" />
                    <telerik:RadGradientStop
                    x:Name="O"
                    Offset="-1"
                    Color="orange" />
                </telerik:GaugeGradientRange>
            </telerik:GaugeRangesDefinition>
        </telerik:RadVerticalGauge.Ranges>
    </telerik:RadVerticalGauge>
</VerticalStackLayout>

2. Define a sample ViewModel and set it as a BindingContext:

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();
        this.BindingContext = new ViewModel();
    }
}
public class ViewModel : NotifyPropertyChangedBase
{
    private double data = 10;
    public double Data
    {
        get =>this.data;
        set { this.UpdateValue(ref this.data, value);}
    }
}

3. DEfine a TelerikUtils class with the attached property implementation:

public static class TelerikUtils
{
    public static readonly BindableProperty MyThicknessProperty =
BindableProperty.CreateAttached("MyThickness", typeof(double), typeof(TelerikUtils), 0.0, propertyChanged: OnMyThicknessChanged);

    public static double GetMyThickness(BindableObject bindable)
    {
        return (double)bindable.GetValue(MyThicknessProperty);
    }

    public static void SetMyThickness(BindableObject bindable, double value)
    {
        bindable.SetValue(MyThicknessProperty, value);
    }

    private static void OnMyThicknessChanged(BindableObject bindable, object oldValue, object newValue)
    {
        GaugeRangesDefinition gaugeRangesDefinition = (GaugeRangesDefinition)bindable;
        double myThickess = (double)newValue;
        gaugeRangesDefinition.StartThickness = myThickess;
    }
}

See Also

• Gauge Overview