WPF Binding to multidimensional array in the xaml

Question

I have trouble to formulate the XAML string to link to a specific element in a multidimensional array.

The DataContext contains the following lines:

Answer 1

By default WPF XAML does not allow binding to a 2D array like this. Only 1D arrays. However, nothing is impossible. Just time consuming. You will have to create a custom class in order to do this and use that as a way of binding.

/// <summary>
/// This class is a bindable encapsulation of a 2D array.
/// </summary>
/// <typeparam name="T"></typeparam>
public class BindableTwoDArray<T> : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    private void Notify(string property)
    {
        var pc = PropertyChanged;
        if (pc != null)
            pc(this, new PropertyChangedEventArgs(property));
    }

    T[,] data;

    public T this[int c1, int c2]
    {
        get { return data[c1, c2]; }
        set
        {
            data[c1, c2] = value;
            Notify(Binding.IndexerName);
        }
    }

    public string GetStringIndex(int c1, int c2)
    {
        return c1.ToString() + "-" + c2.ToString();
    }

    private void SplitIndex(string index, out int c1, out int c2)
    {
        var parts = index.Split('-');
        if (parts.Length != 2)
            throw new ArgumentException("The provided index is not valid");

        c1 = int.Parse(parts[0]);
        c2 = int.Parse(parts[1]);
    }

    public T this[string index]
    {
        get
        {
            int c1, c2;
            SplitIndex(index, out c1, out c2);
            return data[c1, c2]; 
        }
        set
        {
            int c1, c2;
            SplitIndex(index, out c1, out c2);
            data[c1, c2] = value;
            Notify(Binding.IndexerName);
        }
    }

    public BindableTwoDArray(int size1, int size2)
    {
        data = new T[size1, size2];
    }

    public static implicit operator T[,](BindableTwoDArray<T> a)
    {
        return a.data;
    }
}

Then you can bind to XAML:

<TextBlock Text="{Binding MyBindableTwoDArray[2-5]}"/>

Source of solution.

This may affect performance which leads me to question using a multidimensional array to begin with? You may use lists which may be an easier implementation. Take a look at this solution.

Answer 2

You can bind to a Two dimensional array using a MultivalueConverter defined like this :

 class MultiDimensionalCoverter:IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        return (values[0] as String[,])[(int) values[1], (int) values[2]];  
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

that MultiDimensionalCoverter get 3 parameters, the Two Dimention array plus the two indexes, and the Xaml will be like this :

<Window.Resources>
        <wpfApp:MultiDimensionalCoverter x:Key="MultiDimensionalCoverter"/>
    </Window.Resources>
    <Grid>
        <StackPanel>
            <Button Content="{Binding OneDimension[1]}" Width="100" Height="50" />
            <Button Content="{Binding Jagged[1][1]}" Width="100" Height="50" />
            <Button Width="100" Height="50" >
                <Button.Resources>
                    <system:Int32 x:Key="1">1</system:Int32>
                </Button.Resources>
                <Button.Content>
                    <MultiBinding Converter="{StaticResource MultiDimensionalCoverter}">
                        <Binding Path="TwoDimension"/>
                        <Binding Source="{StaticResource 1}"/>
                        <Binding Source="{StaticResource 1}"/>
                    </MultiBinding>
                </Button.Content>
            </Button>
        </StackPanel>
    </Grid>

defining the indexes as properties in your VM is probably more appropriate, i am using fixed value only to demonstrate.