Why isn't the Hourly property being set?

Question

I'm working on a very simple UWP app. I'm using the Template10 framework. The viewmodel for the Main window inherits from Template10's ViewModelBase. Here's the property for Hourly from the viewmodel:

private float hourly;  
public float Hourly  
{  
	get => salaryConvUS.HourlyFloat;  
	set  
	{  
		Set(ref hourly, value); //Template10 method  
		salaryConvUS.HourlyFloat = hourly;  
	}  
}  

And here's the XAML related to the TextBox where I'm binding it:

<TextBox  
	x:Name="HourlyTextBox"  
	Style="{StaticResource CommonTextboxStyle}"  
	Text="{x:Bind ViewModel.Hourly, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource EnforceNumericConvert}}" />  

I've set a breakpoint on the Set() method (line 7) of the C# code. It never breaks at that line. Why not?

Answer 1

To use functions with {x:Bind}, your app's minimum target SDK version must be 14393 or later. You can't use functions when your app targets earlier versions of Windows 10.

Try to use {Binding ....} to replace {x:Bind ....}?

FYI: https://learn.microsoft.com/en-us/windows/uwp/data-binding/function-bindings

Answer 2

Hi, try your converter and test converter like this:

  public class EnforceNumericConvert : IValueConverter
  {
    public object Convert(object value, Type targetType, object parameter, string language)
    {
      return value.ToString();
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
      float par = 0;
      float.TryParse(value.ToString(), out par);
      return par;
    }
  }

Answer 3

Hi Rod, try following demo.

XAML:

<Page
    x:Class="App05.Page05"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App05"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
  <Page.Resources>
    <local:EnforceNumericConvert x:Key="EnforceNumericConvert"/>
    <Style x:Key="CommonTextboxStyle" TargetType="TextBox">
      <Setter Property="Background" Value="LightCoral"/>
    </Style>
  </Page.Resources>
  <StackPanel>
    <TextBox
     x:Name="HourlyTextBox"
     Style="{StaticResource CommonTextboxStyle}"
     Text="{x:Bind ViewModel.Hourly, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource EnforceNumericConvert}}" />
    <!-- TextBlock for testing Hourly value-->
    <TextBlock Text="{x:Bind ViewModel.Hourly, Mode=TwoWay}"/>
  </StackPanel>
</Page>

And code:

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Data;

namespace App05
{
  public sealed partial class Page05 : Page
  {
    public Page05() => this.InitializeComponent();
    public ViewModel ViewModel { get; } = new ViewModel();
  }

  public class ViewModel : INotifyPropertyChanged
  {
    private Data salaryConvUS = new Data();

    private float hourly;
    public float Hourly
    {
      get => salaryConvUS.HourlyFloat;
      set
      {
        Debug.WriteLine(value.ToString());
        Set(ref hourly, value); //Template10 method
        salaryConvUS.HourlyFloat = hourly;
        OnPropertyChanged();
      }
    }
    private void Set(ref float input, float value) =>    input = value;

    public event PropertyChangedEventHandler PropertyChanged;
    internal void OnPropertyChanged([CallerMemberName] string propName = "") =>
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));
  }

  public class Data : INotifyPropertyChanged
  {
    private float _hourlyFloat;
    public float HourlyFloat
    {
      get => this._hourlyFloat;
      set { this._hourlyFloat = value; OnPropertyChanged(); }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    internal void OnPropertyChanged([CallerMemberName] string propName = "") =>
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));
  }

  public class EnforceNumericConvert : IValueConverter
  {
    public object Convert(object value, Type targetType, object parameter, string language)
    {
      return value.ToString();
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
      float par = 0;
      float.TryParse(value.ToString(), out par);
      return par;
    }
  }
}

Answer 4

anonymous user-3316 I do have this in my page's XAML:

<Page.DataContext>
<vm:MainPageViewModel x:Name="ViewModel" />
</Page.DataContext>

In your example you have

public ViewModel ViewModel { get; } = new ViewModel();

in your page's constructor. Do you find that to be better than what I've done?