NumericValidationBehaviorPage.xaml

<?xml version="1.0" encoding="UTF-8"?>
<pages:BasePage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                xmlns:mct="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
                xmlns:pages="clr-namespace:CommunityToolkit.Maui.Sample.Pages"
                x:Class="CommunityToolkit.Maui.Sample.Pages.Behaviors.NumericValidationBehaviorPage"
                xmlns:vm="clr-namespace:CommunityToolkit.Maui.Sample.ViewModels.Behaviors"
                x:TypeArguments="vm:NumericValidationBehaviorViewModel"
                x:DataType="vm:NumericValidationBehaviorViewModel">

    <pages:BasePage.Resources>
        <mct:IsNotNullConverter x:Key="IsNotNullConverter" />
        <Style x:Key="InvalidEntryStyle" TargetType="Entry">
            <Setter Property="TextColor" Value="Red" />
        </Style>
        <Style x:Key="ValidEntryStyle"
               TargetType="Entry">
            <Setter Property="TextColor" Value="Green"/>
        </Style>
    </pages:BasePage.Resources>

    <VerticalStackLayout Padding="{StaticResource ContentPadding}"
                 Spacing="24"
                 VerticalOptions="StartAndExpand">

        <Label Text="The NumericValidationBehavior is a behavior that allows the user to determine if text input is a valid numeric value. For example, an Entry control can be styled differently depending on whether a valid or an invalid numeric input is provided. Additional properties handling validation are inherited from ValidationBehavior"
               TextColor="{StaticResource NormalLabelTextColor}" />

        <Label Text="Text color will be changed according to the configured style in case of an invalid numeric format or when the numeric value is outside of the configured boundaries (min: 1.0, max: 100.0). Maximum decimal places value equals 2." />
        
        <Entry x:Name="SafeEntry" Placeholder="Number" Keyboard="Numeric">
            <Entry.Behaviors>
                <mct:NumericValidationBehavior InvalidStyle="{StaticResource InvalidEntryStyle}"
                                               ValidStyle="{StaticResource ValidEntryStyle}"
                                               Flags="ValidateOnValueChanged"
                                               MinimumValue="1.0"
                                               MaximumValue="100.0"
                                               MaximumDecimalPlaces="2"/>
            </Entry.Behaviors>
        </Entry>

        <Button Clicked="SetEntryValue" Text="Set Entry Value To Null" IsEnabled="{Binding Path=Text, Source={x:Reference SafeEntry}, Converter={StaticResource IsNotNullConverter}}"/>
        <Label Text="After entering text then setting the above Entry value to null, the app will crash because null is not a valid input for NumericValidationBehavior and CommunityToolkit.Maui.Options.SetShouldSuppressExceptionsInBehaviors is not set to true."
               TextColor="{StaticResource NormalLabelTextColor}" />
    </VerticalStackLayout>

</pages:BasePage>