I’m using a custom TextBox to validate input value.
If the input data was invalid, a message box would be shown and the Text in TextBox would be rollback, else update the Model .
In the ViewModel, I used try…finally in set method.
When I entered an invalid value to TextBox, the message box appeared but the Text didn’t be rollback.
But if I used try…catch…finally in set method the Text was rollback.
Here is my code:

ViewModel.cs.

public Value
{
    get => _model.Value;
    set
    {
        try {
                _model.Value = value;
                // Some codes
        }
        catch(Exception) // What's the situation with the catch?
        {
            
        }
        finally
        {
            OnPropertyChanged();

        }
        
    }
}

XAML:

<commonControls:IntegerBox Text="{Binding Path=Value, UpdateSourceTrigger=Explicit, Mode=TwoWay}"
                                    OnLostFocusInvalidValueCommand="{Binding NumericBoxLostFocusCommand}"
                                    >
</commonControls:IntegerBox>

The NumericBoxLostFocusCommand just show the message box.

IntegerBox.cs:

public static readonly DependencyProperty IsValidProperty =
            DependencyProperty.Register(
                nameof(IsValid),
                typeof(bool),
                typeof(IntegerBox),
                new PropertyMetadata(true));

        public bool IsValid
        {
            get => (bool)GetValue(IsValidProperty);
            set => SetValue(IsValidProperty, value);
        }

        public IntegerBox()
        {
            PreviewTextInput += NumericBox_PreviewTextInput;
            TextChanged += NumericBox_TextChanged;
            LostFocus += Numeric_LostFocus;
        }

        protected virtual void Numeric_LostFocus(object sender, RoutedEventArgs e)
        {

            if (sender is TextBox textBox)
            {
                if (!IsValid)
                {
                    OnLostFocusInvalidValueCommand?.Execute(sender);
                }
                var bindingExpression = BindingOperations.GetBindingExpression(textBox, TextBox.TextProperty);
                bindingExpression?.UpdateSource();
                if (IsValid)
                {
                    OnLostFocusValidateValueCommand?.Execute(null);
                }

            }
        }
        
          protected override void NumericBox_TextChanged(object sender, TextChangedEventArgs e)
        {

                if (Text.IsNullOrWhiteSpace() && !Nullable)
                {
                    IsValid = false;
                    ToolTip = ErrorMessages.ERR_EMPTY_INPUT;
                }

                if (MaxValue > MinValue && int.TryParse(Text, out var currentInteger))
                {
                    IsValid = currentInteger >= MinValue && currentInteger <= MaxValue;
                }
            
        }

        protected override void NumericBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
        {
            e.Handled = !IsTextAllowed(e.Text);
        }

        private bool IsTextAllowed(string text)
        {
            return !_integerRegex.IsMatch(text);
        }

Why is there a difference between using and not the catch block?

I tried add the catch block to set method.