Question

If I don’t add explicit accessors to a String property, then data binding doesn’t work. Why is that?
Here is a simple example where a text box is hooked up to a String property.

MainPage.xaml:

<Grid Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
    <TextBlock Text="{Binding Message} />
</Grid>

And the code behind:

public String Message;

public MainPage()
{
    InitializeComponent();
    Message = "Hello World";
    DataContext = this;
}

This does not work, the text box is empty.

However, add property accessors;

public String Message { get; set; };

And now it works.

I can’t see this explained in MSDN Data Binding. Can someone explain it? Don’t properties have an implict set/get accessors? Even so, why can’t data binding just access the property?

Thanks,

Answer 1

public String Message;

This is a field, not a property. Adding getters and setters creates an auto property.
Only properties can be bound to.