string bound to TextBlock in ComboBox doesn't show up

Question

I have a TextBlock in a ComboBox in a C# WPF project bound to a list of 'Envelope' items, which have a string 'Name' and a double 'Weight' property, the former of which I would like to see displayed in the TextBlock.

When I run my program, the ComboBox appears without any text in it. It properly has three unlabeled items in it, and if I view the ItemsSource or SelectedItem of the ComboBox they show the appropriate values, and other code which interacts with the SelectedItem of the ComboBox behaves properly. The only thing that does not work is that the TextBlock contains no text. If I replace the "{Binding Name}" with "au ghdfjlnvgmumar" then the appropriate garbled characters appear in the ComboBox, so it is definitely a problem with the binding. What is the problem, and how can I get around it?

Relevant code:

xaml:

<ComboBox Name="EnvelopeList" HorizontalAlignment="Center" Width="200" >
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                 <TextBlock Text="{Binding Name}" />
            </StackPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

C#:

//main window code
public MainWindow()
{
    InitializeComponent();

    envelopes = new List<Envelope>();
    envelopes.Add(new Envelope("TEST", 0));
    envelopes.Add(new Envelope("HI", 10));

    EnvelopeList.ItemsSource = envelopes;
}

//Envelope class
class Envelope
{
    public string Name;
    public double Weight;

    public Envelope()
    {
        Name = "[None]";
        Weight = 0;
    }
    public Envelope(string n, double w)
    {
        Name = n;
        Weight = w;
    }

    public override string ToString()
    {
        return Name;
    }
}

Answer 1

Name is a field, you can only bind to properties.