Windows Phone更改列表框中textblock的文本

Question

I have a listbox in my xaml page in my windows phone app.

the itemsource of the listbox is set to data coming from the server.

I need to set the text of a textblock/button inside this listbox according to data received from the server.

I cant bind the data directly, neither can I change the data coming from the server.

I need to do something like this:-

if (Data from server == "Hey this is free")
    { Set textblock/button text to free }
else
    { Set textblock/button text to Not Free/Buy }

data from server (for this particular element) can have more than 2-3 types, for example it can be $5, $10, $15, Free or anything else

so only in case of free, I need to set text to free otherwise set it to Not Free/Buy.

How can I access this textblock/button inside the listbox?

Answer 1

You should use a Converter . Here is how:

Start by declaring a class that implements IValueConverter . This is where you will test the value received from the server and return the appropriate value.

public sealed class PriceConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        if (value.ToString() == "Hey this is free")
        {
            return "free";
        }
        else
        {
            return "buy";
        }
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

At the top of your page, add the Namepace declaration:

xmlns:local="clr-namespace:namespace-where-your-converter-is"

Declare the Converter:

<phone:PhoneApplicationPage.Resources>
    <local:PriceConverter x:Key="PriceConverter"/>
</phone:PhoneApplicationPage.Resources>

And use it on the TextBlock:

<TextBlock Text="{Binding Price,Converter={StaticResource PriceConverter}}"/>

Answer 2

You can define a value converter :

public class PriceConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value == null) return String.Empty;
            var text = (string) value;
            return text.Contains("Free") ? "text to free" : text;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

and use in in your xaml

<TextBlock Text="{Binding Text, Converter={StaticResource PriceConverter}}">