How to use Boolean to control visibility of item dynamically

Question

How can I dynamically use a Boolean that I created to control the visibility of an item via a decision making statement? I created one in my control class but don't know how to link it to the item myself (i.e. a TextBlock).

Update

Page1.xaml

<Page
    x:Class="MyApp.Page1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:MyApp"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:local1="using:MyApp.UserControls"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    <StackPanel>
        <Border BorderBrush="LightGreen" BorderThickness="3" Margin="5">
            <StackPanel>
                <TextBlock Text="UserControl"/>
                <Border BorderBrush="Red" BorderThickness="3" Margin="5">
                    <local1:MyUserControl1 x:Name="uc"/>
                </Border>
            </StackPanel>
        </Border>
    </StackPanel>
</Page>

Page1.xaml.cs

namespace MyApp
{
    public sealed partial class Page1 : Page
    {
        public Page1()
        {
            this.InitializeComponent();

            this.uc.TitleText = "TitleText";
            this.uc.ShowTitleText = true;
        }
    }
}

MyUserControl1.xaml

<UserControl
    x:Class="MyApp.UserControls.MyUserControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:MyApp.UserControls"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300"
    d:DesignWidth="400">
    <UserControl.Resources>
        <local:BooleanToVisibilityConverter x:Key="b2vconv"/>
    </UserControl.Resources>

   <Grid x:Name="grd">
     <Grid.RowDefinitions>
       <RowDefinition Height="Auto"/>
       <RowDefinition Height="Auto"/>
     </Grid.RowDefinitions>

     <TextBlock Grid.Row="0" x:Name="txtTitle" Text="{Binding TitleText}" Visibility="{Binding ShowTitleText, Converter={StaticResource b2vconv}}"/>
     <Border Grid.Row="1" BorderBrush="Green" BorderThickness="3">
       <TextBlock Text="Body"/>
     </Border>
   </Grid>
</UserControl>

MyUserControl1.xaml.cs

namespace MyApp.UserControls
{
    public sealed partial class MyUserControl1 : UserControl
    {
        public MyUserControl1()
        {
            this.InitializeComponent();
            this.grd.DataContext = this;
        }

        public static readonly DependencyProperty TitleTextProperty =
          DependencyProperty.Register("TitleText", typeof(string), typeof(MyUserControl1),
            new PropertyMetadata(""));

        public static readonly DependencyProperty ShowTitleTextProperty =
          DependencyProperty.Register("ShowTitleText", typeof(bool), typeof(MyUserControl1),
            new PropertyMetadata(true));

        public string TitleText
        {
            get => GetValue(TitleTextProperty).ToString();
            set { SetValue(TitleTextProperty, value); }
        }

        public bool ShowTitleText
        {
            get => (bool)GetValue(ShowTitleTextProperty);
            set { SetValue(ShowTitleTextProperty, value); }
        }
    }

    public class BooleanToVisibilityConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, string language) =>
            (bool)value ? Visibility.Visible : Visibility.Collapsed;

        public object ConvertBack(object value, Type targetType, object parameter, string language) =>
            (Visibility)value == Visibility.Visible;
    }
}

Answer 1

Hi, to use assign in code try following demo:

<Page
    x:Class="App1.Page03"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App03"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
  <StackPanel>
    <Border BorderBrush="Green" BorderThickness="3" Margin="5">
      <StackPanel>
        <TextBlock Text="Text for UserControl"/>
        <TextBox x:Name="tb" Text="first title" TextChanged="tb_TextChanged"/>
        <TextBlock Text="Switch to show UserControl"/>
        <CheckBox x:Name="cb" IsChecked="True"/>
      </StackPanel>
    </Border>
    <Border BorderBrush="LightGreen" BorderThickness="3" Margin="5">
      <StackPanel>
        <TextBlock Text="UserControl"/>
        <Border BorderBrush="Red" BorderThickness="3" Margin="5">
          <local:UserControlFacilitiesSummary x:Name="uc"/>
        </Border>
      </StackPanel>
    </Border>
  </StackPanel>
</Page>

---

using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace App1
{
  public sealed partial class Page03 : Page
  {
    public Page03()
    {
      this.InitializeComponent();
      this.uc.TitleText = this.tb.Text;
      this.uc.ShowTitleText = this.cb.IsChecked.Value;
      this.cb.Checked += cb_Checked_Unchecked;
      this.cb.Unchecked += cb_Checked_Unchecked;
    }

    private void tb_TextChanged(object sender, TextChangedEventArgs e) => this.uc.TitleText = this.tb.Text;
    private void cb_Checked_Unchecked(object sender, RoutedEventArgs e) => this.uc.ShowTitleText = this.cb.IsChecked.Value;
  }

}

<UserControl
    x:Class="App03.UserControlFacilitiesSummary"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:App03"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300"
    d:DesignWidth="400">
  <UserControl.Resources>
    <local:BooleanToVisibilityConverter x:Key="b2vconv"/>
  </UserControl.Resources>
  <Grid x:Name="grd">
    <Grid.RowDefinitions>
      <RowDefinition Height="auto"/>
      <RowDefinition Height="auto"/>
    </Grid.RowDefinitions>
    <TextBlock Grid.Row="0" Text="{Binding TitleText}" Visibility="{Binding ShowTitleText, Converter={StaticResource b2vconv}}"/>
    <Border Grid.Row="1" BorderBrush="Green" BorderThickness="3">
      <TextBlock Text="Body"/>
    </Border>
  </Grid>

</UserControl>

using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Data;

namespace App03
{

  public sealed partial class UserControlFacilitiesSummary : UserControl
  {
    public UserControlFacilitiesSummary()
    {
      this.InitializeComponent();
      this.grd.DataContext = this;
    }

    public static readonly DependencyProperty TitleTextProperty =
      DependencyProperty.Register("TitleText", typeof(string), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(""));

    public static readonly DependencyProperty ShowTitleTextProperty =
      DependencyProperty.Register("ShowTitleText", typeof(bool), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(true));

    public string TitleText
    {
      get => GetValue(TitleTextProperty).ToString();
      set { SetValue(TitleTextProperty, value); }
    }

    public bool ShowTitleText
    {
      get => (bool)GetValue(ShowTitleTextProperty);
      set { SetValue(ShowTitleTextProperty, value); }
    }
  }

  public class BooleanToVisibilityConverter : IValueConverter
  {
    public object Convert(object value, Type targetType, object parameter, string language) =>
        (bool)value ? Visibility.Visible : Visibility.Collapsed;

    public object ConvertBack(object value, Type targetType, object parameter, string language) =>
        (Visibility)value == Visibility.Visible;

  }
}

Answer 2

I think UserControlFacilitiesSummary code behind should be like

public sealed partial class UserControlFacilitiesSummary
{
    public UserControlFacilitiesSummary()
    {
        InitializeComponent();
        txtTitle.Text = TitleText ?? string.Empty;
        txtTitle.Visibility = ShowTitleText ? Visibility.Visible : Visibility.Collapsed;
        txtSubtitle.Text = TitleText ?? string.Empty;
        txtSubtitle.Visibility = ShowTitleText ? Visibility.Visible : Visibility.Collapsed;
        txtFacilities.Text = TextFacilities ?? string.Empty;
    }

    public static readonly DependencyProperty TitleTextProperty = DependencyProperty.Register(
        nameof(TitleText), typeof(string), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(default(string), (o, args) =>
        {
            var dependencyObject = (UserControlFacilitiesSummary)o;
            dependencyObject.txtTitle.Text = (string)args.NewValue ?? string.Empty;
        }));

    public string TitleText
    {
        get => (string)GetValue(TitleTextProperty);
        set => SetValue(TitleTextProperty, value);
    }

    public static readonly DependencyProperty ShowTitleTextProperty = DependencyProperty.Register(
        nameof(ShowTitleText), typeof(bool), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(default(bool), (o, args) =>
        {
            var dependencyObject = (UserControlFacilitiesSummary)o;
            dependencyObject.txtTitle.Visibility = (bool)args.NewValue ? Visibility.Visible : Visibility.Collapsed;
        }));

    public bool ShowTitleText
    {
        get => (bool)GetValue(ShowTitleTextProperty);
        set => SetValue(ShowTitleTextProperty, value);
    }

    public static readonly DependencyProperty TextSubtitleProperty = DependencyProperty.Register(
        nameof(TextSubtitle), typeof(string), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(default(string), (o, args) =>
        {
            var dependencyObject = (UserControlFacilitiesSummary)o;
            dependencyObject.txtSubtitle.Text = (string)args.NewValue ?? string.Empty;
        }));

    public string TextSubtitle
    {
        get => (string)GetValue(TextSubtitleProperty);
        set => SetValue(TextSubtitleProperty, value);
    }

    public static readonly DependencyProperty ShowTextSubtitleProperty = DependencyProperty.Register(
        nameof(ShowTextSubtitle), typeof(bool), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(default(bool), (o, args) =>
        {
            var dependencyObject = (UserControlFacilitiesSummary)o;
            dependencyObject.txtSubtitle.Visibility = (bool)args.NewValue ? Visibility.Visible : Visibility.Collapsed;
        }));

    public bool ShowTextSubtitle
    {
        get => (bool)GetValue(ShowTextSubtitleProperty);
        set => SetValue(ShowTextSubtitleProperty, value);
    }

    public static readonly DependencyProperty TextFacilitiesProperty = DependencyProperty.Register(
        nameof(TextFacilities), typeof(string), typeof(UserControlFacilitiesSummary),
        new PropertyMetadata(default(string), (o, args) =>
        {
            var dependencyObject = (UserControlFacilitiesSummary)o;
            dependencyObject.txtFacilities.Text = (string)args.NewValue ?? string.Empty;
        }));

    public string TextFacilities
    {
        get => (string) GetValue(TextFacilitiesProperty);
        set => SetValue(TextFacilitiesProperty, value);
    }
}

and your XAML something like

<UserControl [...]>
    <controls:DropShadowPanel HorizontalAlignment="Left">
        <Grid x:Name="grd">
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>

            <StackPanel Grid.Row="0" HorizontalAlignment="Left">
                <TextBlock x:Name="txtFacilities" Style="{StaticResource SubheaderTextBlockStyle}"/>
            </StackPanel>
            <StackPanel Grid.Row="1" Orientation="Vertical">
                <TextBlock x:Name="txtTitle" />
                <TextBlock x:Name="txtSubtitle" />
            </StackPanel>
        </Grid>
    </controls:DropShadowPanel>
</UserControl>

Answer 3

Hi, try following demo with your code, which I have changed a little bit.

<Page  
    x:Class="App1.Page02"  
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
    xmlns:local="using:App02"  
    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.DataContext>  
    <local:ViewModel/>  
  </Page.DataContext>  
  <StackPanel>  
    <Border BorderBrush="Green" BorderThickness="3" Margin="5">  
      <StackPanel>  
        <TextBlock Text="Text for UserControl"/>  
        <TextBox Text="{Binding TextValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>  
        <TextBlock Text="Switch to show UserControl"/>  
        <CheckBox IsChecked="{Binding SwitchValue, Mode=TwoWay}"/>  
      </StackPanel>  
    </Border>  
    <Border BorderBrush="LightGreen" BorderThickness="3" Margin="5">  
      <StackPanel>  
        <TextBlock Text="UserControl"/>  
        <Border BorderBrush="Red" BorderThickness="3" Margin="5">  
          <local:UserControlFacilitiesSummary TitleText="{Binding TextValue}" ShowTitleText="{Binding SwitchValue}"/>  
        </Border>  
      </StackPanel>  
    </Border>  
  </StackPanel>  
</Page>  

---------------------------------------

using System.ComponentModel;  
using System.Runtime.CompilerServices;  
using Windows.UI.Xaml.Controls;  
  
namespace App02  
{  
  public class ViewModel : INotifyPropertyChanged  
  {  
    private string _textValue = "Start-Text";  
    public string TextValue { get => this._textValue; set { this._textValue = value; OnPropertyChanged(); } }  
  
    private bool _switchValue = true;  
    public bool SwitchValue { get => this._switchValue; set { this._switchValue = value; OnPropertyChanged(); } }  
  
    public event PropertyChangedEventHandler PropertyChanged;  
    internal void OnPropertyChanged([CallerMemberName] string propName = "") =>  
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));  
  }  
}  
  

------------------------------------------------------------

<UserControl  
    x:Class="App02.UserControlFacilitiesSummary"  
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
    xmlns:local="using:App02"  
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"  
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"  
    mc:Ignorable="d"  
    d:DesignHeight="300"  
    d:DesignWidth="400">  
  <Grid x:Name="grd">  
    <Grid.RowDefinitions>  
      <RowDefinition Height="auto"/>  
      <RowDefinition Height="auto"/>  
    </Grid.RowDefinitions>  
    <TextBlock Grid.Row="0" Text="{Binding TitleText}" Visibility="{Binding ShowTitleText}"/>  
    <Border Grid.Row="1" BorderBrush="Green" BorderThickness="3">  
      <TextBlock Text="Body"/>  
    </Border>  
  </Grid>  
</UserControl>  
  

------------------------------------------------

using Windows.UI.Xaml;  
using Windows.UI.Xaml.Controls;  
  
namespace App02  
{  
  
  public sealed partial class UserControlFacilitiesSummary : UserControl  
  {  
    public UserControlFacilitiesSummary()  
    {  
      this.InitializeComponent();  
      this.grd.DataContext = this;  
    }  
  
    public static readonly DependencyProperty TitleTextProperty =  
      DependencyProperty.Register("TitleText", typeof(string), typeof(UserControlFacilitiesSummary), new PropertyMetadata(""));  
  
    public static readonly DependencyProperty ShowTitleTextProperty =  
      DependencyProperty.Register("ShowTitleText", typeof(bool), typeof(UserControlFacilitiesSummary),   
        new PropertyMetadata(true));  
  
    public string TitleText  
    {  
      get { return GetValue(TitleTextProperty).ToString(); }  
      set { SetValue(TitleTextProperty, value); }  
    }  
  
    public Visibility ShowTitleText  
    {  
      //get { return (bool)GetValue(ShowTitleTextProperty); }  
      get { return ((bool)GetValue(ShowTitleTextProperty)) ? Visibility.Visible : Visibility.Collapsed; }  
      set { SetValue(ShowTitleTextProperty, value); }  
    }  
  }  
}  

Answer 4

What about this?

UserControlName.ShowTitleText = false;

How can this be used properly?