Cannot perform equivalent text binding with TextBox

Question

In my program I have a TextBlock that is bound to a property value in a data model. I would like to change this TextBlock to a TextBox so that it is editable, but would still like to bind text to it. The problem is, when I change the TextBlock to a TextBox, my binding does not work, and the TextBox appears blank.

The property that I am binding to is of a custom class that I have in my program.

This is the property:

//Property for Display Name
public MultiItemString DisplayName {}

This is the MultiItemString class:

public class MultiItemString : INotifyPropertyChanged
{
    private readonly string[] _keys;
    private readonly MultiItemString[] _nestedItems;

    readonly bool _resourceKey;
    private readonly bool _nestedMultiItemStrings;

    public MultiItemString(IEnumerable<string> keys, bool resourceKey = true)
    {
        _keys = keys.ToArray();
        _resourceKey = resourceKey;

        LanguageChange.LanguageChagned += (sender, args) => RaisePropertyChanged("");
    }

    public MultiItemString(IEnumerable<MultiItemString> nestedItems)
    {
        _nestedItems = nestedItems.ToArray();
        foreach (var multiItemString in _nestedItems)
        {
            multiItemString.PropertyChanged += (s, e) => RaisePropertyChanged("Value");
        }
        _nestedMultiItemStrings = true;
    }

    public string Key
    {
        get
        {
            if (_keys != null && _keys.Length != 0) return _keys[0];
            return null;
        }
    }

    public string Value
    {
        get
        {
            var sb = new StringBuilder();
            if (_nestedMultiItemStrings)
            {
                foreach (var MultiItemString in _nestedItems)
                {
                    sb.Append(MultiItemString.Value);
                }
            }
            else
            {
                foreach (var key in _keys)
                {
                    sb.Append(_resourceKey ? (string)Application.Current.Resources[key] : key);
                }
            }
            return sb.ToString();
        }
    }

    public override string ToString()
    {
        return Value;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    void RaisePropertyChanged(string propertyName)
    {
        var temp = PropertyChanged;
        if (temp != null)
            temp(this, new PropertyChangedEventArgs(propertyName));
    }
}

My xaml:

<TextBox Text="{Binding Model.DisplayName}" Height="28" HorizontalAlignment="Left" Name="title_TB" VerticalAlignment="Top" Width="Auto" FontWeight="Bold" FontSize="14" Margin="5,2,0,0" />

How can I bind this property to a TextBox as it's text value, just like I do with TextBlock?

Answer 1

This should work:

<TextBox Text="{Binding Model.DisplayName.Value}" Height="28" HorizontalAlignment="Left" Name="title_TB" VerticalAlignment="Top" Width="Auto" FontWeight="Bold" FontSize="14" Margin="5,2,0,0" />

And, update Value property to have setter:

private string _thisShouldBeAValidField ;
    public string Value
        {
            get
            {
if(_thisShouldBeAValidField!=null) return _thisShouldBeAValidField;
                var sb = new StringBuilder();
                if (_nestedMultiItemStrings)
                {
                    foreach (var MultiItemString in _nestedItems)
                    {
                        sb.Append(MultiItemString.Value);
                    }
                }
                else
                {
                    foreach (var key in _keys)
                    {
                        sb.Append(_resourceKey ? (string)Application.Current.Resources[key] : key);
                    }
                }
                return sb.ToString();
            }
    set{
    _thisShouldBeAValidField = value;
    }
        }