Binding StringFormat in Windows Phone

Question

I develop silverlight app for windows phone 8. I bind integer value in LongListSelector for example 123. And I want to make it looks like 000123

<phone:LongListSelector ItemsSource="{Binding AllValues}">
  <phone:LongListSelector.ItemTemplate>   
    <DataTemplate>
     <StackPanel>
       <TextBlock x:Name="ValueBlock" 
                  Text="{Binding ValueValue}"
                  HorizontalAlignment="Left" 
                  VerticalAlignment="Center" 
                  Style="{StaticResource PhoneTextLargeStyle}"/>
...

I know StringFormat can do this, but the problem is number of leading zeros is always different and I want to bind it from ViewModel.

... 
Text="{Binding ValueValue}, StringFormat=\{0:D6\}"
...

How can I bind a number after D in StringFormat?

Answer 1

You can't bind the StringFormat part of a binding expression. What you can do instead is add another property to the view model like "ValueDisplay".

public string ValueDisplay
{
    get { return string.Format("{0:" + ValueFormat + "}", ValueValue); }
}

public string ValueFormat
{
    get { return _valueFormat; }
    set
    {
        _valueFormat = value;
        RaisePropertyChanged("ValueDisplay");
    }
}
private string _valueFormat;