Question

I just made my first converter to convert from int to string. I have a combobox fill with integers(years) but if the value is 0 I want the combobox to show ‘All’.

This is my converter:

public class IntToString : IValueConverter
{
     public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value != null)
            {
                int intY = (int)value;

                if (intY == 0)
                {
                    String strY = "All";
                    return strY;
                }
                else
                {
                    return intY.ToString();
                }
            }

            return String.Empty;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {

        }
    }

In XAML where should I set the converter ? I tried in the ItemsSource of the combobox:

ItemsSource="{Binding YearsCollection, Converter={StaticResource intToStringYearConverter}}"

But I always get InvalidcastException on this line:

int intY = (int)value;

Answer 1

The problem is that you are trying to convert the entire collection rather than just one item from the collection.

You would want to do something like this:

<ListBox ItemsSource="{Binding YearsCollection}">
    <ListBox.ItemTemplate>
        <DataTemplate>
             <Border DataContext="{Binding Converter={StaticResource intToStringYearConverter}">
             ...
             </Border>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>