I have a simple user control to display a hyperlink in a textblock:

LinkTextBlock.xaml:

```
<TextBlock >
    <Hyperlink NavigateUri="{Binding Url, ElementName=root}" >
        <TextBlock Text="{Binding Text, ElementName=root}" />
    </Hyperlink>   
</TextBlock>

```

LinkTextBlock.xaml.cs:

```
public static readonly DependencyProperty UrlProperty = DependencyProperty.Register("Url", typeof (string), typeof (LinkTextBlock));
public string Url
{
    get { return (string) GetValue(UrlProperty); }
    set { SetValue(UrlProperty, value); }
}
public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof (string), typeof (LinkTextBlock));
public string Text
{
    get { return (string) GetValue(TextProperty); }
    set { SetValue(TextProperty, value); }
}

```

Then, in a DataTemplate for a ListBox I have:

```
<Controls:LinkTextBlock Text="{Binding Email}" Url="{Binding Email}" />

```

When I run the application, it seems to work perfectly. The control shows the hyperlinks correctly and there are no apparent problems. However, when I look at the Output window I get exceptions, one for each ListBox item:

> 
> System.Windows.Data Error: 22 : Cannot
>  convert '' from type '' to
>  type 'System.Uri' for 'en-US' culture
>  with default conversions; consider
>  using Converter property of Binding.
>  NotSupportedException:'System.NotSupportedException:
>  UriTypeConverter cannot convert from
>  (null). at
>  System.ComponentModel.TypeConverter.GetConvertFromException(Object
>  value) at
>  System.ComponentModel.TypeConverter.ConvertFrom(ITypeDescriptorContext
>  context, CultureInfo culture, Object
>  value) at
>  System.UriTypeConverter.ConvertFrom(ITypeDescriptorContext
>  context, CultureInfo culture, Object
>  value) at
>  MS.Internal.Data.DefaultValueConverter.ConvertHelper(Object
>  o, Type destinationType,
>  DependencyObject targetElement,
>  CultureInfo culture, Boolean
>  isForward)'
> 
> 
> 

Why is this happening? I know the binding error is a result of the binding to NavigateURI.
Do you have any suggestions for me? What can I do about it? I really appreciate your inputs.

Thanks