Wpf Checkbox content UnderscoreConverter in ResourceDictionary?

I will show you my demo to use Converter in ResourceDictionary.
Step 1: Create a model named MyModel which used for binding data to CheckBox.

 public class MyModel: INotifyPropertyChanged  
    {  
        public string Name { get; set; }  
        public bool StatusForCheckBox { get; set; }  
  
        public string myBrushes;  
        public string MyBrushes  
        {  
            get { return myBrushes; }  
            set  
            {  
                myBrushes = value;  
                NotifyPropertyChanged("MyBrushes");  
            }  
        }  
  
        public event PropertyChangedEventHandler PropertyChanged;  
        public void NotifyPropertyChanged(string propertyName)  
        {  
            if (PropertyChanged != null)  
            {  
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));  
            }  
        }  
    }  

Step 2：Create a list for CheckBox in the MainWindow.xaml

 <Grid>  
        <ListBox x:Name="myList" Width="400" Height="400" HorizontalAlignment="Right">  
            <ListBox.ItemTemplate>  
                <DataTemplate >  
                    <CheckBox Content="{Binding Name,Mode=TwoWay}" IsChecked="{Binding StatusForCheckBox,Mode=TwoWay}" Background="{Binding MyBrushes,Mode=TwoWay}"/>  
                </DataTemplate>  
            </ListBox.ItemTemplate>  
        </ListBox>  
    </Grid>  

Step 3: Binding the data for the list in MainWindow.xaml.cs:

 public MainWindow()  
        {  
            InitializeComponent();  
            ObservableCollection<MyModel> lt = new ObservableCollection<MyModel>()  
            {  
                new MyModel{Name="Test1",StatusForCheckBox=false },  
                new MyModel{Name="Test2",StatusForCheckBox=true },  
                new MyModel{Name="Test3",StatusForCheckBox=false}  
            };  
            myList.ItemsSource = lt;  
        }  

Step 4: Create a Converter named MyConverter, and its code is:

 public class MyConverter : IValueConverter  
    {  
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)  
        {  
            MyModel model = value as MyModel;  
            bool bValue = model.StatusForCheckBox;  
            if (bValue != true)  
            {  
                model.MyBrushes = "Red";  
                return model;  
            }  
            else  
            {  
                model.MyBrushes = "Yellow";  
                return model;  
            }  
        }  
  
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)  
        {  
            throw new NotImplementedException();  
        }  
    }  

Step 5：Add the style in ResourceDictionary:

<Application.Resources>  
        <Style TargetType="CheckBox">  
            <Setter Property="Content">  
                <Setter.Value>  
                    <Binding>  
                        <Binding.Converter>  
                            <local:MyConverter></local:MyConverter>  
                        </Binding.Converter>  
                    </Binding>  
                </Setter.Value>  
            </Setter>  
        </Style>  
    </Application.Resources>  

Then you can get the result picture:

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Hi Daisy ,

Thanks for your reply. I tried to implement UnderscoreConverter in your above project but it's not working for me.

public class UnderscoreConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            MyModel model = value as MyModel;
            if (model.Name is string s)
                return s.Replace("_", "__");
            return null;
        }
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return null;
        }
    }

<Application.Resources>
        <Style TargetType="CheckBox">
            <Setter Property="Content">
                <Setter.Value>
                    <Binding>
                        <Binding.Converter>
                            <local:UnderscoreConverter/>
                        </Binding.Converter>
                    </Binding>
                </Setter.Value>
            </Setter>
        </Style>
    </Application.Resources>

I must be doing something fundamentally wrong. In your example value property is of type 'MyModel' is there a way we make UnderscoreConverter that targets the checkbox content's text property directly because I have different types defining my checkbox in views.

I understand one way out is to use TextBlock to represent CB contents but I cannot use TextBlock in my project.

Kind regards,
Harry